27 research outputs found
Human papillomavirus 16 L2 inhibits the transcriptional activation function, but not the DNA replication function, of HPV-16 E2
In this study we analysed the outcome of the interaction between HPV-16 L2 and E2 on the transactivation and DNA replication functions of E2. When E2 was expressed on its own, it transactivated a number of E2-responsive promoters but co-expression of L2 led to the down-regulation of the transcription transactivation activity of the E2 protein. This repression is not mediated by an increased degradation of the E2 protein. In contrast, the expression of L2 had no effect on the ability of E2 to activate DNA replication in association with the viral replication factor E1. Deletion mutagenesis identified L2 domains responsible for binding to E2 (first 50 N-terminus amino acid residues) and down-regulating its transactivation function (residues 301–400). The results demonstrate that L2 selectively inhibits the transcriptional activation property of E2 and that there is a direct interaction between the two proteins, although this is not sufficient to mediate the transcriptional repression. The consequences of the L2–E2 interaction for the viral life cycle are discussed
Error sources and data limitations for the prediction ofsurface gravity: a case study using benchmarks
Gravity-based heights require gravity values at levelled benchmarks (BMs), whichsometimes have to be predicted from surrounding observations. We use EGM2008 andthe Australian National Gravity Database (ANGD) as examples of model and terrestrialobserved data respectively to predict gravity at Australian national levelling network(ANLN) BMs. The aim is to quantify errors that may propagate into the predicted BMgravity values and then into gravimetric height corrections (HCs). Our results indicatethat an approximate ±1 arc-minute horizontal position error of the BMs causesmaximum errors in EGM2008 BM gravity of ~ 22 mGal (~55 mm in the HC at ~2200 melevation) and ~18 mGal for ANGD BM gravity because the values are not computed atthe true location of the BM. We use RTM (residual terrain modelling) techniques toshow that ~50% of EGM2008 BM gravity error in a moderately mountainous regioncan be accounted for by signal omission. Non-representative sampling of ANGDgravity in this region may cause errors of up to 50 mGals (~120 mm for the Helmertorthometric correction at ~2200 m elevation). For modelled gravity at BMs to beviable, levelling networks need horizontal BM positions accurate to a few metres, whileRTM techniques can be used to reduce signal omission error. Unrepresentative gravitysampling in mountains can be remedied by denser and more representative re-surveys,and/or gravity can be forward modelled into regions of sparser gravity
DETERMINISTICALLY-MODIFIED INTEGRAL ESTIMATORS OF GRAVITATIONAL TENSOR
The Earth's global gravity field modelling is an important subject in Physical Geodesy. For this purpose different satellite gravimetry missions have been designed and launched. Satellite gravity gradiometry (SGG) is a technique to measure the second-order derivatives of the gravity field. The gravity field and steady state ocean circulation explorer (GOCE) is the first satellite mission which uses this technique and is dedicated to recover Earth's gravity models (EGMs) up to medium wavelengths. The existing terrestrial gravimetric data and EGM scan be used for validation of the GOCE data prior to their use. In this research, the tensor of gravitation in the local north-oriented frame is generated using deterministically-modified integral estimators involving terrestrial data and EGMs. The paper presents that the SGG data is assessable with an accuracy of 1-2 mE in Fennoscandia using a modified integral estimatorby the Molodensky method. A degree of modification of 100 and an integration cap size of for integrating terrestrial data are proper parameters for the estimator
Actuaciones irrelevantes e incumplimiento de las condiciones materiales exigidas para la interrupción del plazo de prescripción del derecho a liquidar
"Este trabajo ha obtenido el Accésit Premio Estudios Financieros 2010 en la Modalidad de
TRIBUTACION".La interrupción del plazo de prescripción de la obligación tributaria por una actuación administrativa tendente a la regularización de la situación fiscal exige, además de la notificación de la actuación, que la misma esté efectivamente destinada a comprobar el correcto cumplimiento de las obligaciones tributarias. De ahí surge la necesidad de analizar la posible existencia de actuaciones irrelevantes en el procedimiento inspector que, en ocasiones, han sido denominadas diligencias - argucia por no cumplir el requisito material de estar dirigidas a hacer avanzar la regularización de la situación tributaria del contribuyente. Tales actuaciones irrelevantes presentan diferente tipologías por lo que se procede a sistematizar las diversas causas de pérdida de la capacidad de interrupción del plazo de prescripción. Entre las mismas destacan las actuaciones nulas de pleno derecho, los requerimientos de información a la que ya puede acceder por sí misma la Administración o los relativos a cuestiones o períodos diferentes de los que son objeto de inspección, o las actuaciones anodinas
Oxidative dehydrogenation of propane over Cr2O3/Al2O3 and Cr2O3 catalysts: effects of loading, precursor and surface area
Several alumina supported chromium oxide catalysts were prepared by varying the chromium oxide loading, precursors and surface areas of the support. The prepared catalysts were characterized using BET, XRD, XPS and UV-VIS spectroscopic techniques. The monolayer limit was observed to be similar to9 mumol Cr/m(2). Below monolayer limits, surface chromium oxide species were present irrespective of precursors and surface area of the support. The activity of the prepared samples was tested for ODH of propane. It was observed that the supported chromium oxide samples were active for the ODH reaction and that propene was the major product. The activity and selectivity increased with loading up to monolayer limits and decreased for higher loadings. Bulk Cr2O3 was also studied for the ODH reaction and found to behave differently than the Cr2O3/Al2O3 catalysts. The efficiency of each surface chromium oxide species on alumina to carry out the ODH of propane, the turn over frequency (TOF), was relatively independent of chromium oxide loading for the monolayer catalysts. However, it appears that a constant fraction of the surface chromium oxide species is active for the ODH of propane. This constant fraction of the surface chromium oxide phase is given by the polymeric chromium oxide species. The inactive fraction is given by the monomeric chromium oxide species that is not reducible. (C) 2002 Elsevier Science B.V. All rights reserved