284 research outputs found
Three–Dimensional Seismic Diffraction Imaging for Detecting Near-Surface Inhomogeneities
One of the problems encountered in a variety of near-surface investigations is detecting and mapping localized inhomogeneities. Typical examples of such inhomogeneous sources are cavities, caves and tunnels. Different methods for detecting shallow subsurface sources utilizing seismic waves diffracted by these sources were proposed by many researchers in the last three decades. Most of these methods suggest that every subsurface point is a possible location of a point diffractor. Imaging of the diffractors is based on a spatial summation of the diffracted wavefield along diffraction time surfaces (defined by source-receiver geometry) in 2D or 3D space. The summation is performed with a fixed velocity value estimated from velocity analysis of the diffraction data. In this study, we present a path integral summation approach, where for every subsurface point the wavefield is stacked together along all possible diffraction time surfaces having a common apex at a given time. The result of the imaging is a 3D volume in which prominent diffraction anomalies appear at spatial locations close to the imaged sources. This path integral summation approach has been successfully tested on synthetic data and further applied at several sites with known subsurface sources
Multifocusing imaging over an irregular topography
If seismic data are acquired over an irregular topography, standard elevation statics methods may be inaccurate because the assumption of vertical raypaths will no longer be valid. An effective solution to the problem of irregular topography can be found through the use of the multifocusing method, in which large supergathers of seismic traces are stacked, each of which can span many common midpoint (CMP) gathers. This can be done by extending the multifocusing moveout formula to explicitly account for nonzero elevations of the source and receiver, as well as their horizontal coordinates.Implementation of this formula into the multifocusing algorithm is straightforward because estimating the necessary raypath information (i.e., emergence angles) is an integral part of the algorithm. The extended multifocusing moveout correction can be applied directly to the data acquired in areas of irregular topography without the need for prior elevation static corrections. Synthetic tests on such data show that the proposed technique results in a better alignment of reflection events
Protection against growth of MUC1/sec transfected mammary tumor cells is mediated by an effector cell with perforin-dependent cytotoxicity
Characterization of a hormonally induced reverse transcriptase (RT) from the human breast cancer cell line T47D: a possible involvement in human breast cancer
MUC1 gene overexpressed in breast cancer: structure and transcriptional activity of the MUC1 promoter and role of estrogen receptor alpha (ERα) in regulation of the MUC1 gene expression
BACKGROUND: The MUC1 gene encodes a mucin glycoprotein(s) which is basally expressed in most epithelial cells. In breast adenocarcinoma and a variety of epithelial tumors its transcription is dramatically upregulated. Of particular relevance to breast cancer, steroid hormones also stimulate the expression of the MUC1 gene. The MUC1 gene directs expression of several protein isoforms, which participate in many crucial cell processes. Although the MUC1 gene plays a critical role in cell physiology and pathology, little is known about its promoter organization and transcriptional regulation. The goal of this study was to provide insight into the structure and transcriptional activity of the MUC1 promoter. RESULTS: Using TRANSFAC and TSSG soft-ware programs the transcription factor binding sites of the MUC1 promoter were analyzed and a map of transcription cis-elements was constructed. The effect of different MUC1 promoter regions on MUC1 gene expression was monitored. Different regions of the MUC1 promoter were analyzed for their ability to control expression of specific MUC1 isoforms. Differences in the expression of human MUC1 gene transfected into mouse cells (heterologous artificial system) compared to human cells (homologous natural system) were observed. The role of estrogen on MUC1 isoform expression in human breast cancer cells, MCF-7 and T47D, was also analyzed. It was shown for the first time that synthesis of MUC1/SEC is dependent on estrogen whereas expression of MUC1/TM did not demonstrate such dependence. Moreover, the estrogen receptor alpha, ERα, could bind in vitro estrogen responsive cis-elements, EREs, that are present in the MUC1 promoter. The potential roles of different regions of the MUC1 promoter and ER in regulation of MUC1 gene expression are discussed. CONCLUSION: Analysis of the structure and transcriptional activity of the MUC1 promoter performed in this study helps to better understand the mechanisms controlling transcription of the MUC1 gene. The role of different regions of the MUC1 promoter in expression of the MUC1 isoforms and possible function of ERα in this process has been established. The data obtained in this study may help in development of molecular modalities for controlled regulation of the MUC1 gene thus contributing to progress in breast cancer gene therapy
Properties of retrovirus-like particles produced by a human breast carcinoma cell line: immunological relationship with mouse mammary tumor virus proteins.
Quantitative measurement of odor detection thresholds using an air dilution olfactometer, and association with genetic variants in a sample of diverse ancestry
Genetic association studies require a quantitative and reliable method for odor threshold assessment in order to examine the contribution of genetic variants to complex olfactory phenotypes. Our main goal was to assess the feasibility of a portable Scentroid air dilution olfactometer for use in such studies. Using the Scentroid SM110C and the SK5 n-butanol Sensitivity Kit (IDES Canada Inc.), n-butanol odor thresholds were determined for 182 individuals of diverse ancestry (mean age: 20.4 ± 2.5 years; n = 128 female; n = 54 male). Threshold scores from repeat participants were used to calculate a test–retest reliability coefficient, which was statistically significant (r = 0.754, p < 0.001, n = 29), indicating that the Scentroid provides reliable estimates of odor thresholds. In addition, we performed a preliminary genetic analysis evaluating the potential association of n-butanol odor thresholds to six single-nucleotide polymorphisms (SNPs) putatively involved in general olfactory sensitivity (GOS). The results of multiple linear regression analysis revealed no significant association between the SNPs tested and threshold scores. However, our sample size was relatively small, and our study was only powered to identify genetic markers with strong effects on olfactory sensitivity. Overall, we find that the Scentroid provides reliable quantitative measures of odor detection threshold and is well suited for genetic studies of olfactory sensitivity
Interactions of the 67 kDa laminin receptor and its precursor with laminin
The 67LR (67 kDa laminin receptor) enables cells to interact with components of the extracellular matrix. The molecule is derived from the 37LRP (37 kDa laminin receptor precursor); however, the precise molecular mechanism of this conversion is unknown. Recombinant 37LRP, expressed in and purified from Escherichia coli, bound to human laminin in a SPR (surface plasmon resonance) experiment. 67LR isolated from human breast-cancer-derived cells in culture was also shown to bind to laminin by SPR. However, the kinetics of association are qualitatively different. 37LRP, but not 67LR, binds to heparan sulfate. The binding of 37LRP to heparan sulfate did not affect the interaction of 37LRP with laminin. In contrast, heparan sulfate reduces the extent of binding of laminin to 67LR. Taken together, these results show that 37LRP has some of the biological activities of 67LR, even prior to the conversion event. However, the conversion affects the sites of interaction with both laminin and heparan sulfate
Recommendations for digitally recording, recirculating, and remixing holocaust testimony
Testimony has always raised ethical issues, especially in relation to questions of provenance, integrity, ownership, and authenticity. Nevertheless, it has become one of the most powerful sources for Holocaust education. Meeting a Holocaust survivor in-person has been a particular tenet of educational experiences. Looking forward, we face dual challenges: (1) the decline in numbers of living witnesses to the Holocaust, (2) the increasing prevalence of digital technologies. It has been somewhat taken for granted that the latter offers solutions for dealing with the former.
Media technologies have been integral to the dissemination of Holocaust testimony since the 1940s. From the attempts to smuggle out material evidence of witnessing atrocities on photographic film to the scraps of paper and writing implements used to document experiences and wishes for the future, from the Oneg Shabbat archives of the Warsaw Ghetto to the 'Scrolls of Auschwitz'. It is however in the immediate post-war period with Boder's wire recordings that spoken testimony of events after the fact began to be recorded at scale. Some survivors later chose to publish their testimonies in memoir form. Then, in 1979, the Holocaust Survivors Film Project launched which developed into the Fortunoff Archives at Yale University. At Yale, audio-video
testimonies were captured on tape, which not only preserved the speech patterns alongside narrative content of testimonies, but gestures and body language also. In moments of silence, viewers of testimony could now see the testimony-giver's body, any emotional reaction, and their gaze. There was a range of academic writing (from Lawrence Langer to Georges Agamben and Jean-François Lyotard) that addressed the significance of these 'silences', in different ways.
With video then digital interventions in testimony recording, there has been increasingly attention given to the visual elements of testimonial narratives. This has been particularly demonstrated by the projects of the USC Shoah Foundation. Starting in a similar vein to Fortunoff, with audio-visual testimonies, the Foundation (initially established by the profits for Schindler's List (1994)), has since turned its attention to interactive interfaces (IWitness) use of machine learning (Dimensions in Testimony) and virtual reality ('Lola' and 'The Last Goodbye') and 360-degree on-location testimonies to explore the affordances that emerging technologies can offer for the sustainability of testimony into the future. Whilst of course, historical concerns about testimony will always remain, digital technologies introduce new possibilities and challenges, which needs to be better understood across the sector.
This report serves as an important first step in this work. It was created as part of the research project 'Participatory Workshops - Co-Designing Standards for Digital Interventions in Holocaust Memory and Education', which is one thread of the larger Digital Holocaust Memory Project at the University of Sussex.
The participatory workshops have focused on six themes, each of which brought together a different range of expertise to discuss current challenges and consider possible recommendations for the future. The themes were:
• AI and machine learning
• Digitising material evidence
• Recording, recirculating and remixing testimony
• Social media
• Virtual memoryscapes
• Computer games
In this report, you will find the recommendations and a suggestion of who could bear responsibility to take each of these on; a summary of the workshop discussions; and a list of the participants who contributed to this work. There will also be a complementary action plan published alongside this report. The recommendations and discussion presented here summarise participant opinions, which might not reflect the opinions of project leads or any individual participant in full, or all participants in consensus. Whilst we have offered participants the opportunity to review and discuss the development of these guidelines, we have tried to retain differing perspectives rather than suggest there was homogeneity in opinion. The discussion presented is an
aggregation of professional opinions informed by a diverse range of experiences and expertise. We present ideas collectively, rather than attributing specific points to participants. All participants are, however, acknowledged as contributors to this report.
This document does not claim to be the last word on digitally recording, recirculating, and remixing Holocaust testimony, rather we recognise that this is very much the beginning of a longer conversation. We hope that the immediate recommendations suggested in these guidelines will help organisations and individuals to prioritise the work needed to work effectively with Holocaust testimony in digital spaces
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