87 research outputs found
Reservoir fracture characterizations from seismic scattered waves
The measurements of fracture parameters, such as fracture orientation, fracture density and fracture compliance, in a reservoir is very important for field development and exploration. Traditional seismic methods for fracture characterization include shear wave birefringence (Gaiser and Dok, 2001; Dok et al., 2001; Angerer et al., 2002; Vetri et al., 2003) and amplitude variations with offset and azimuth (AVOA) (Ruger, 1998; Shen et al., 2002; Hall et al., 2003; Liu et al., 2010; Lynn et al., 2010). These methods are based on the equivalent medium theory with the assumption that fracture dimension and spacing are small relative to the seismic wave length, so a fracture zone behaves like an equivalent anisotropic medium. But fractures on the order of seismic wave length are also very important for enhanced oil recovery, and they are one of the important subsurface scattering sources that generate scattered seismic waves.
Willis et al. (2006) developed the Scattering Index method to extract the fracture scattering characteristics by calculating the transfer funtion of a fracture zone. Fang et al. (2011) proposed a modification of the SI method (the Fracture Transfer Function (FTF) method) that leads to a more robust fracture characterization. In this paper, we use both laboratory data and field data to explore the capability of the FTF method.Eni-MIT Energy Initiative Founding Member Progra
Violence against primary school children with disabilities in Uganda: a cross-sectional study.
BACKGROUND: 150 million children live with disabilities globally, and a recent systematic review found 3 to 4 times the levels of violence versus non-disabled children in high income countries. However, almost nothing is known about violence against disabled children in lower income countries. We aim to explore the prevalence, patterns and risk factors for physical, sexual and emotional violence among disabled children attending primary school in Luwero District, Uganda. METHODS: We performed a secondary analysis of data from the baseline survey of the Good Schools Study. 3706 children and young adolescents aged 11-14 were randomly sampled from 42 primary schools. Descriptive statistics were computed and logistic regression models fitted. RESULTS: 8.8% of boys and 7.6% of girls reported a disability. Levels of violence against both disabled and non-disabled children were extremely high. Disabled girls report slightly more physical (99.1% vs 94.6%, p = 0.010) and considerably more sexual violence (23.6% vs 12.3%, p = 0.002) than non-disabled girls; for disabled and non-disabled boys, levels are not statistically different. The school environment is one of the main venues at which violence is occurring, but patterns differ by sex. Risk factors for violence are similar between disabled and non-disabled students. CONCLUSIONS: In Uganda, disabled girls are at particular risk of violence, notably sexual violence. Schools may be a promising venue for intervention delivery. Further research on the epidemiology and prevention of violence against disabled and non-disabled children in low income countries is urgently needed
Massive multiplication of genome and ribosomes in dormant cells (akinetes) of Aphanizomenon ovalisporum (Cyanobacteria)
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in The ISME Journal 6 (2012): 670–679, doi:10.1038/ismej.2011.128.Akinetes are dormancy cells commonly found among filamentous cyanobacteria, many of which are toxic and/or nuisance, bloom-forming species. Development of akinetes from vegetative cells is a process that involves morphological and biochemical modifications. Here we applied a single cell approach to quantify genome and ribosome content of akinetes and vegetative cells in Aphanizomenon ovalisporum (Cyanobacteria). Vegetative cells of A. ovalisporum were naturally polyploid and contained on average 8 genome copies per cell. However, the chromosomal content of akinetes increased up to 450 copies, with an average value of 119 genome copies per akinete, 15 fold higher that in vegetative cells. Based on fluorescence in situ hybridization with a probe targeting 16S rRNA and detection with confocal laser scanning microscopy we conclude that ribosomes accumulated in akinetes to a higher level than that found in vegetative cells. We further present evidence that this massive accumulation of nucleic acids in akinetes is likely supported by phosphate supplied from inorganic polyphosphate bodies that were abundantly present in vegetative cells, but notably absent from akinetes. These results are interpreted in the context of cellular investments for proliferation following long term dormancy, as the high nucleic acid content would provide the basis for extended survival, rapid resumption of metabolic activity and cell division upon germination.Supported by the Gruss Lipper Foundation research award (AS). This study was part of the Joint German-Israeli-Project (FKZ 02WT0985, WR803) funded by the German Ministry of Research and Technology (BMBF) and Israel Ministry of Science and Technology (MOST)
YM155 Induces EGFR Suppression in Pancreatic Cancer Cells
YM155, which inhibits the anti-apoptotic protein survivin, is known to exert anti-tumor effects in various cancers, including prostate and lung cancer. However, there are few reports describing the inhibitory effect of YM155 on human pancreatic cancers that highly express survivin. Here, we tested the effects of YM155 on a variety of cancer cell lines, including pancreatic cancer cells. We found that YM155 exerts an anti-proliferative effect in pancreatic cancer cells, inducing cell death through suppression of XIAP (X-linked inhibitor of apoptosis) as well as survivin without affecting the anti-apoptotic proteins Bcl-xL or Mcl-1. YM155 also inhibited tumor growth in vivo, reducing the size of pancreatic cancer cell line MIAPaCa-2 xenografts by 77.1% on day 31. Western blot analyses further showed that YM155 downregulated phosphoinoside 3-kinase (PI3K) expression and reduced the levels of phosphorylated (activated) extracellular signal-regulated kinase (ERK) and STAT3 (signal transducer and activator of transcription 3) in PANC-1 cells. Interestingly, we also found that YM155 downregulated the epidermal growth factor receptor (EGFR) in various cancer cell lines and induced the EGFR phosphorylation and ubiquitination of EGFR in PANC-1 cells. YM155 also modestly promoted the ubiquitination of survivin and XIAP. Therefore, YM155 acts through modulation of EGFR and survivin expression to subsequently reduce survival. We suggest that YM155 has potential as a therapeutic agent in the treatment of pancreatic cancer
Start-up success of freelancers New microeconometric evidence from the German Socio-Economic Panel
If certain start-up characteristics will indicate a business success, knowing such characteristics
could generate more successful start-ups and more efficient start-up counseling. Our study
will contribut e to this by quantifying individual success determinants of freelance start-ups.
The data base for the microeconometric analyses of the survival of the first three years is a
revised German Socio-Economic Panel (SOEP) for 1992 until 2002, which allows to
incorporate institutional, personal and family/household socio-economic variables. We
describe and discuss the datawork to achieve compatible information over time within a
revised GSOEP and present microeconometric rare events logit, logit and probit results.
The start-up success measured as the probability to survive the first three years is first of all
influenced by an active labour force participation with its acquired skills and working
experiences just before the start-up period (rank 1), followed by a non-university degree as
the highest general human capital indicator (rank 2), a general (non-linear) experience
indicated by age (rank 3) and the business related background (rank 4) as the type of liberal
profession in the group of the liberal medical professions and the liberal technical and
scientific professions
The distribution and re-distribution of income of selfemployed as freelancers and entrepreneurs in Europe
The economic transformations of modern industrial societies have changed the labor markets in terms of
industrial relations and occupational structure. The transformation of the traditional welfare state, the
deregulation of the labor markets, the technological change and the reorganization of industrial structures
influenced strongly the attitude of individuals towards their preferred labor contract. The structural change of the
occupational structure was one of the results of this tendency. In particular the self-employed and freelancers
have been affected and are a driving factor of labor market changings. On the one side the value of autonomy
regarding industrial relations is becoming more important for employees. On the other side employers want to
get rid of social security contributions. As a result the multitudinousness of these professions increased.
The increasing varieties of occupations among the self-employed and freelancers influenced strongly their
income distribution. Recent studies for Germany have shown a great dispersion and a heterogeneous structure of
earnings in particular of freelancers (liberal professions) and self-employed. Though there are a variety of
international income distribution studies, but – as to the best to our knowledge – no study focusing on the selfemployed
and freelancers within the total labor force. In our study we concentrate on the income distribution of
self-employed and freelancers in different European countries. Based on the Luxembourg Income Study (LIS)
we analyze five different European countries and the United States structured by different types of welfare states
according to Esping Anderson. We analyze income distributional aspects, an occupational decomposition à la
Shorrocks, and re-distributional effects of the tax and transfer systems
The Distribution and Re-Distribution of Income of Selfemployed as Freelancers and Entrepreneurs in Europe
Use of 3D Spheroid Models for the Assessment of RT Response in Head and Neck Cancer
Radiotherapy (RT) is a key player in the treatment of head and neck cancer (HNC). The RT response, however, is variable and influenced by multiple tumoral and tumor microenvironmental factors, such as human papillomavirus (HPV) infections and hypoxia. To investigate the biological mechanisms behind these variable responses, preclinical models are crucial. Up till now, 2D clonogenic and in vivo assays have remained the gold standard, although the popularity of 3D models is rising. In this study, we investigate the use of 3D spheroid models as a preclinical tool for radiobiological research by comparing the RT response of two HPV-positive and two HPV-negative HNC spheroid models to the RT response of their corresponding 2D and in vivo models. We demonstrate that HPV-positive spheroids keep their higher intrinsic radiosensitivity when compared to HPV-negative spheroids. A good correlation is found in the RT response between HPV-positive SCC154 and HPV-negative CAL27 spheroids and their respective xenografts. In addition, 3D spheroids are able to capture the heterogeneity of RT responses within HPV-positive and HPV-negative models. Moreover, we demonstrate the potential use of 3D spheroids in the study of the mechanisms underlying these RT responses in a spatial manner by whole-mount Ki-67 and pimonidazole staining. Overall, our results show that 3D spheroids are a promising model to assess the RT response in HNC
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