1,447 research outputs found
Escape and Naturalization of Tagetes patula in Western Ethiopia
This study was carried out on an introduced ornamental - Tagetes patula L., which has escaped cultivation and has been naturalized in Benishangul-Gumuz National Regional State (bgnrs), western Ethiopia. Another introduced ornamental - Zinnia elegans Jacq. and the native species - Bidens prestinaria (Sch. Bip.) Cufod. were included in some of the experiments for comparison. Pre-prepared semi-structured interviews were administered, on the arrival, spread and impact of T. patula. The result showed that the escaped T. patula has no negative impact on the daily life of people, except weeding in farmlands. T. patula was found associated with species that prefer shade and moisture in semi-natural vegetation. It produces a large number of relatively small propagules and has a seed bank. These characters might enhance its invasive ability and make it a potential threat to grazing fields and natural landscapes in western Ethiopia. The result of fire simulation experiment, however, revealed that fire had an effect on seed germination, as there was no seed germination at higher temperature treatment (120°C/5 minutes). The annual fire occurring existing in the woodlands of bgnrs might not allow invasion by the species that are not adapted to fire, like T. patula and Z. elegans. In the absence of annual woodland fire, invasion of the woodland vegetation in bgnrs by T. patula and Z. elegans is most likely to occur
A Deep \u3cem\u3eXMM-Newton\u3c/em\u3e Observation of the Quasar 3C 287
We report on an XMM-Newton observation of the z = 1.055 quasar and Gigahertz Peaked Spectrum (GPS) source 3C 287. Our 62.3 ks observation provides an exceptional X-ray view of a prominent member of this important subclass of active galactic nuclei (AGNs). The X-ray spectra of 3C 287 are consistent with a simple absorbed power law with a spectral index of Π= 1.72 ± 0.02. Our fits imply a bolometric luminosity of L = 5.8 ± 0.2 à 1045 erg s-1 over the 0.3-10.0 keV band; this gives a mass lower limit of M BH min \u3e= 4.6 à 107 M sun assuming X-rays contribute 10% of the bolometric luminosity and radiation at the Eddington limit. Iron emission lines are common in the X-ray spectra of many AGNs, but the observed spectra appear to rule out strong emission lines in 3C 287. The simple power-law spectrum and the absence of strong emission lines may support a picture where our line of sight intersects a relativistic jet. Milliarcsecond radio imaging of 3C 287 appears to support this interpretation. We discuss our results in the context of different AGNs subclasses and the possibility that GPS sources harbor newly formed black hole jets
Characterisation of autophagy disruption in the ileum of pigs infected with Lawsonia intracellularis
Lawsonia intracellularis is the aetiological agent of proliferative enteropathy, an enteric disease endemic in swine. Survival in its intracellular niche of the ileum epithelial lining requires the capacity to subvert, repress or exploit the host immune response to create an environment conducive to bacterial propagation. To better understand how L. intracellularis survives in its intracellular niche, we have performed an investigation into the dynamic relationship between infection and the host autophagy response by immunohistochemistry in experimentally infected porcine ileum samples. Beclin1, a protein required early in the autophagy pathway was observed to be distributed with a basal to apical concentration gradient in the crypts of healthy piglets, whilst infected piglets were observed to have no gradient of distribution and an increase in the presence of Beclin1 in crypts with histological characteristics of L. intracellularis residence. Detecting microtubule-associated protein light chain 3 (LC3) is used as a method for monitoring autophagy progression as it associates with mature autophagosomes. For LC3 there was no notable change in signal intensity between crypts with characteristic L. intracellularis infection and healthy crypts of uninfected pigs. Finally, as p62 is degraded with the internal substrate of an autophagosome it was used to measure autophagic flux. There was no observed reduction or redistribution of p62. These preliminary results of the autophagy response in the ileum suggest that L. intracellularis affects autophagy. This disruption to host ileum homeostasis may provide a mechanism that assists in bacterial propagation and contributes to pathogenesis
Two kinds of procedural semantics for privative modification
In this paper we present two kinds of procedural semantics for privative modification. We do this for three reasons. The first reason is to launch a tough test case to gauge the degree of substantial agreement between a constructivist and a realist interpretation of procedural semantics; the second is to extend Martin-L Ìfâs Constructive Type Theory to privative modification, which is characteristic of natural language; the third reason is to sketch a positive characterization of privation
Targets for the reduction of antibiotic use in humans in the Transatlantic Taskforce on Antimicrobial Resistance (TATFAR) partner countries
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