69 research outputs found
Dissection of c-myc domains involved in S phase induction of NIH 3T3 fibroblasts
No full textThe product of the c-myc proto-oncogene is an important regulator of cell proliferation and apoptosis in murine fibroblasts. Addition of the tumor promoter, phorbol myristate acetate (PMA), prevents apoptotic cell death induced by low serum concentrations in NIH3T3 cells that constitutively express and are transformed by v-myc. The protective effect of PMA allowed us to analyse the ability of normal c-Myc and Myc deletion mutants to induce serum starved, untransformed NIH3T3 cells to enter S phase. By microinjecting these quiescent cells with wild type and mutant human c-myc plasmids, we showed that full length c-myc is able to induce S phase entry in presence of PMA, but that c-Myc mutants that delete amino acids delta 7/91, delta 41/53, delta 56/103, delta 106/143, delta 265/317 and delta 414/433 are totally inactive. c-Myc did not shorten the period before entry into S phase, since Myc overexpressing cells entered S phase with the same kinetics as control cells when both were stimulated with 20% fetal calf serum (FCS). However, c-Myc overexpression did increase the percentage of cells entering S phase when these cells were stimulated with 2% fetal calf serum. Interestingly, this ability to enhance stimulation by a suboptimal concentration of FCS was retained to a significant degree by Myc mutants that delete amino acids delta 41/53, delta 56/103 or delta 265/317. Finally, Myc mutants that delete delta 106/143 or delta 414/433 exerted a dominant negative effect on S phase entry both in quiescent cells stimulated with 2% FCS and in unsynchronized, cycling cells
Fracture Mode Analysis, Geomechanics, Petrophysics, and Fracture Characterization: An Experimental Investigation on Whitby Shales and Various Other Rock Types
No full textThe rapidly decreasing reserves of conventional gas has forced oil and gas industries to conduct more exploration on unconventional resources, like shale gas. To produce gas from shales in economically viable manner, stimulation techniques like hydraulic fracturing are required. One important factor for a successful hydraulic fracturing is knowing the fracture characteristics such as the fracture mode occurrence. Unfortunately, the factors controlling the fracture mode occurrence are not known yet. This study tries to find out the factors controlling the fracture mode occurrence by investigating the relation between fracture angle, confining pressure, and several rock properties. The fracture mode analysis being developed in this study suggests that for low strength rock like Bad Bentheim sandstone (46.65 MPa) and Indiana limestone (36.5 MPa), fracture modes are not dependent to the confining pressure. Fractures are already at mode II at zero confining pressure, while stronger rocks like Belgium limestone and Granite (125 and 128 MPa respectively) show fracture mode I at zero confining pressure. The experiments convey that the strength of the rock, which is related to its porosity, is the dominant factor controlling the occurrence of fracture mode I and mode II. This study also evaluates the prospectivity of the Whitby mudstone formation in the United Kingdom, which is a depositionally- and time-equivalent shale to the Posidonia Shale Formation (PSF). The PSF is one of the potential resource rocks for shale gas exploration in the Netherlands. Brittleness indices and fraccability indices of WMF from various methods are also determined and analyzed in this study. The results of WMF characterization show that WMF has high heterogeneity, which could imply that it is less favorable for hydraulic fracturing. Comparing the results of WMF to other producing gas shale shows that the WMF has a low range in: porosity, Young’s modulus, and quartz content, and high range in: laminations, and clay contents, suggesting that WMF is less potential for the shale gas resource. However, based on its characteristics, if WMF is divided into four zones, our experiments show that several zones (top and bottom part of WMF) can be considered as the most favorable ones for hydraulic fracturing in the WMF formation.Section Petroleum EngineeringSection Petroleum EngineeringCivil Engineering and Geoscience
Fraccability determination of a Posidonia Shale Formation analogue through geomechanical experiments and micro-CT fracture propagation analysis
No full textGas resources in The Netherlands are steadily running scarce, therefore alternative gas resources are necessary. One of those alternatives present in the Dutch subsurface is shale gas, present in among others the Posidonia Shale Formation (PSF). Little is known about this formation and drilled cores are rare. This study therefore focuses on a time and depositional equivalent in the U.K.: the Whitby Mudstone Formation (WMF). Stimulating the production of a reservoir by hydraulic fracturing (fraccing) is necessary in order to produce the gas economically viable. To determine the prospectivity of this fraccing (fraccability), several concepts are assessed, e.g. Brittleness Index (B.I.) (Rickman et al. 2008), Fracture Toughness (KIC) (Lawn & Wilshaw 1975) and Fraccability Index (F.I.) (Jin et al. 2014). The fraccability of the WMF is determined through geomechanical experiments and X-ray micro-computed tomography fracture propagation analysis. Samples were taken along an exhumed outcrop 8 meter in height. To account for anisotropy, experiments were conducted at different angles to the bedding. The applied unconfined stress to create new fractures in repetitive tests, depends on the interplay of the already present fractures. Fractures that do not reach the sample’s edges, simulate a triaxial ellipsoid shape and follow a sublinear aperture-length ratio. The WMF results show low KIC-values, which is favorable, but scattered B.I. and F.I. values, which do not provide a clear view on the prospectivity of the WMF. In general, the B.I. and F.I. provide important insights in fraccability, though its significance is relative. Values can be compared with other datasets or intervals under the condition that the same limits of experimentally measured Young’s Modulus, Poisson’s Ratio and Fracture Toughness in these concepts are applied. The WMF thus exhibits a questionable fraccability. Near the formation’ top and bottom, fraccing is preferred opposed to the middle. But weathering and exhumation of the WMF samples has certainly had its effect on the quality and uncertainty of the results.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
Laboratory and greenhouse assessment of plant availability of organic N in animal manure
No full textLaboratory data (thermal fractionation, pepsin extraction, C:No ratio) of dung and manure were mutually compared and contrasted with plant-availability of organic N (No) as found in a greenhouse experiment according to the double-pot technique. Two types of fresh cow dung (one with a relatively wide and the other with a relatively narrow C:No ratio) and four types of manure (from poultry, sheep, pigs and cow) were compared with ammonium nitrate as chemical reference fertilizer. Relative effectiveness of organic N (REo) was used as characteristic; it was calculated as the fraction of organic N that has the same availability to plants as inorganic N. REo for poultry and sheep manure could not be assessed, probably because of NH3 volatilization causing direct damage to plants and N losses. REo values decreased in the order: dung with narrow C:No > dung with wide C:No > pig manure > cow manure. Thermal fractionation did not provide a suitable index of plant-availability of organic N. Pepsin extracted organic N gave a positive, and C:No ratio a negative relationship with REo. Also between pepsin extracted organic N and C:No ratio a negative relationship was found. As C:No ratio is relatively easy to determine, it is considered the most practical laboratory index for plant availability of organic N in animal manures low in ammonia. When using the double-pot technique, application rates of manure types high in ammonia should be restricte
Long, detailed first-person narrative on the political battle between Friends of
No full textLong, detailed first-person narrative on the political battle between Friends of Bigelow and the Western Mountains Foundation (WMF), over WMF\u27s proposal to build a machine-groomed cross-county ski trail inside the Bigelow Preserve. Author Lance Tapley, who organized Friends of Bigelow 30 years ago and has remained an activist, details the anatomy of the compromise that was eventually reached, and the emotional toll that came with it. With a focus on comments by Larry Warren, president of WMF; Dick Fecteau, chairman of Friends of Bigelow; and Patrick McGowan, commissioner of conservation
Câncer de laringe- evolução da doença no Brasil no período de 2002 a 2011.
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Saúde Pública
Microstructural, Petrophysical and Anisotropy Analysis of a Posidonia Shale Analogue
No full textIt is well-known that conventional gas resources are diminishing, forcing experts to consider exploration of unconventionals. But commercially viable production of unconventional gas requires applying the reservoir stimulation technique hydraulic fracturing. One of the formations classified so far as potential interesting formation for shale gas exploration in the Netherlands is the Lower Jurassic Posidonia Shale Formation (PSF). There are vast numbers of data published regarding the characterization of the PSF, however nothing on the variation and heterogeneity. Since knowledge on this is crucial for proper hydraulic fracturing, this thesis elaborates on the variety in certain characteristics and on the anisotropy within the shale. As up to date exploration drilling is prohibited in the Netherlands, material to conduct research on is scarce. Therefore research is conducted on a time and depositional analogue of the PSF: the Whitby Mudstone Formation (WMF) in the U.K. Porosity and matrix densities are quantified with variation in the section, as well as mineral composition analysis based on XRF analysis. Velocity measurements are also conducted at multiple heights in the section and in multiple directions to elaborate on anisotropy of the material. Attenuation anisotropy is incorporated as well as Thomsen’s parameters combined with elastic parameters, e.g. Young’s modulus and Poisson’s ratio, to quantify the elastic anisotropy. The aim of this thesis is to assess whether the integrated results prove to be promising for gas exploration in the PSF-analogue, and if so, what the most promising horizons within this formation could be. The results show that the WMF is highly anisotropic and that none of the horizons prove to be obviously favorable for gas exploration. However, based on changes in the characteristics, 4 subsections are obtained. The upper and lower part of the WMF do show relatively enhanced prospects compared to the middle. But this is a cautiously taken conclusion as some characteristics seem to contradict each other and some less decisive parameters point towards other favorable subsections. The pessimistic results might be a distorted view caused by the many induced fractures or weathering, but one thing is clear, this time analogue of the Posidonia Shale Formation is no Barnett Shale equivalent.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
Constituição e Transdemocracia: uma análise crítico-histórica
No full textAccompanying Shorske, a critical-historical analysis of the work of Marcelo Neves is proposed in his book Constitution and Law in peripherical modernity: a theoretical approach and an interpretation of the Brazilian case, in the 2018 edition, of the publisher WMF Martins Fontes. The work was originally prefaced by Niklas Luhmann. This preface remains in the 2018 edition. Thus, the book covers important social issues, describing the relevance of its author nowadays.Acompanhando Shorske, propõe-se uma análise críticohistórica da obra de Marcelo Neves em seu livro Constituição e Direito na Modernidade Periférica: uma Abordagem Teórica e uma Interpretação do Caso Brasileiro, na edição de 2018, da editora WMF Martins Fontes. A obra foi originalmente prefaciada por NiklasLuhmann. Esse prefácio se conserva na edição de 2018. Assim, o livro percorre importantes questões sociais, descrevendo a pertinência de seu autor na atualidade
User-Specific Rating Prediction for Mobile Applications via Weight-based Matrix Factorization
No full textWith the dramatic growth of mobile application (app) markets, users can find various apps with any functionalities they desire in these markets. However, the huge amounts of apps make it quite a challenge for users to discover good apps efficiently. Previous studies recommend apps by considering all apps equal without capturing the specific interests of each individual user. To address this problem, we propose a model called Weight-based Matrix Factorization (WMF), which can capture user-specific interests and give a more accurate prediction on these apps. WMF views each user as a document and each app as a word, and calculates the weight of each app for target users. The weights are calculated by employing term frequency inverse document frequency (TF-IDF) algorithm, which are then introduced into matrix factorization to predict app ratings. Comprehensive experiments are conducted on a real-world datasets with 5057 users and 4496 apps. The experimental results show that WMF achieves a convincing performance and surpasses other existing prediction models.CPCI-S(ISTP)[email protected]; [email protected]; [email protected]; [email protected]
A Comparitive Study On The Perfermance Of The InSAR Phase Filtering Approches In The Spatial And The Wavelet Domains
No full textIn this paper, we studied and tested different filtering approaches of the SAR interferograms in the spatial and wavelet domains. In
the spatial domain, we applied the classic Lee filter and the Weighted Median Filter WMF. In the wavelet domain, we tested a noise
reduction algorithm WInP proposed by López and Fàbregàs and its enhanced version FAMM developed by Abdelfattah and Bouzid.
Those filters are validated with different SAR interferograms provided by Radarsat-2, Envisat, ERS-2 and COSMO-SkyMed SLC data
acquired over regions of Mahdia and Ben Guerden in Tunisia. The aim of this study is to select the optimal filtering approach with
respect to the fringe pattern in the interferogram. This selection is based on the Digital Elevation Model error computed between the
filtered unwrapping phase image and the Global ASTER DEM of the same regions and verified with simulated interferograms
- …
