63 research outputs found
Statistical Saliency Model incorporating motion saliency and an application to driving
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.At head of title on title-page: Master of Science thesis.Includes bibliographical references (p. 43-44).This thesis extends the Statistical Saliency Model to include motion as a feature, enabling it to compute the saliency of video sequences more effectively. The motion feature is represented as optical flow and incorporated into the model. The model is validated by testing its capability in predicting reaction time performance in a driving simulator. We find that the model does help predict reaction time and some eye-movements in some simulated driving tasks.by Alvin Raj.S.M
How a statistical encoding in the periphery affects perception
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 159-163).Recent understanding in human vision suggests that the periphery compresses visual information to a set of summary statistics. Some visual information is robust to this lossy compression, but others, like spatial location and phase are not perfectly represented, leading to ambiguous interpretations. Using the statistical encoding, we can visualize the information available in the periphery to gain intuitions about human performance in visual tasks, which have implications for user interface design, or more generally, whether the periphery encodes sufficient information to perform a task without additional eye movements. The periphery is most of the visual field. If it undergoes these losses of information, then our perception and ability to perform tasks efficiently are affected. We show that the statistical encoding explains human performance in classic visual search experiments. Based on the statistical understanding, we also propose a quantitative model that can estimate the average number of fixations humans would need to find a target in a search display. Further, we show that the ambiguities in the peripheral representation predict many aspects of some illusions. In particular, the model correctly predicts how polarity and width affects the Pinna-Gregory illusion. Visualizing the statistical representation of the illusion shows that many qualitative aspects of the illusion are captured by the statistical ambiguities. We also investigate a phenomena known as Object Substitution Masking (OSM), where the identity of an object is impaired when a sparse, non-overlapping, and temporally trailing mask surrounds that object. We find that different types of grouping of object and mask produce different levels of impairment. This contradicts a theory about OSM which predicts that grouping should always increase masking strength. We speculate some reasons for why the statistical model of the periphery may explain OSM.by Alvin Andrew Raj.Ph.D
The Public\u27s Perception of an Earthquake Early Warning System: A Study on Factors Influencing Continuance Intention
This paper investigates the perceptions of the New Zealand public towards the Android Earthquake Alert (AEA) system, a public-facing earthquake early warning system. Specifically, it examines the public’s continuance intention towards the AEA system and the influencing factors of satisfaction, confirmation, perceived usefulness, and perceived trust. To gather insights into the public’s perceptions regarding the AEA system, this study distributed online surveys following two separate earthquake alert events on 12 October and 22 October 2021. A total of 524 and 671 participants responded to the two events’ surveys, providing valuable data for analysis and exploration. Structural Equation Modelling of the two datasets revealed that the continuance model fit the data to some extent, especially on the significance of perceived usefulness and perceived trust to continuance intention. However, the results also showed varying results for satisfaction’s relationship with perceived trust and continuance intention. These findings underscore the need for further investigation into the role of satisfaction and perceived trust, considering the evolving nature of EEW technologies and users’ familiarity over time. The descriptive and inferential analysis results raised concerns about potential confusion around the alerts’ source and highlighted the question of responsibility and liability for EEW. Overall, this study contributes to understanding continuance intention in the EEW context and provides insights into the public’s perception of the AEA system in New Zealand. The findings have implications more broadly for EEW systems’ design, implementation, and communication strategies
Enhanced Recovery after Urological Surgery: A Contemporary Systematic Review of Outcomes, Key Elements, and Research Needs
Enhanced Recovery after Surgery (ERAS) programs are multimodal care pathways that aim to decrease intra-operative blood loss, decrease postoperative complications, and reduce recovery times
Novel Survivin Inhibitor for Suppressing Pancreatic Cancer Cells Growth via Downregulating Sp1 and Sp3 Transciption Factors
Background/Aims: Targeting survivin, an anti-apoptotic protein and mitotic regulator, is considered as an effective therapeutic option for pancreatic cancer (PaCa). Tolfenamic acid (TA) showed anti-cancer activity in pre-clinical studies. A recent discovery demonstrated a copper(II) complex of TA (Cu-TA) can result in higher activity. In this study, the ability of Cu-TA to inhibit survivin and its transcription factors, Specificity protein (Sp) 1 and 3 in PaCa cell lines and tumor growth in mouse xenograft model were evaluated.
Methods: Cell growth inhibition was measured in MIA PaCa-2 and Panc1 cells for 2 days using CellTiter-Glo kit. Sp1, Sp3 and survivin expression (by Western blot and qPCR), apoptotic cells and cell cycle phase distribution (by flow cytometry) were evaluated. A pilot study was performed using athymic nude mice [treated with vehicle/Cu-TA (25 or 50 mg/kg) 3 times/week for 4 weeks.
Results: The IC50 value for Cu-TA was about half than TA. Both agents repressed the protein expression of Sp1/Sp3/survivin, Cu-TA was more effective than TA. Especially effect on survivin inhibition was 5.2 (MIA PaCa-2) or 6.4 (Panc1) fold higher and mRNA expression of only survivin was decreased. Apoptotic cells increased with Cu-TA treatment in both cell lines, while Panc1 showed both effect on apoptosis and cell cycle (G2/M) arrest. Cu-TA decreased the tumor growth in mouse xenografts (25 mg/kg: 48%; 50 mg/kg: 68%). Additionally, there was no change observed in mice body weights, indicating no overt toxicity was occurring.
Conclusion: These results show that Cu-TA can serve as an effective survivin inhibitor for inhibiting PaCa cell growth
Microgeometry capture using an elastomeric sensor
We describe a system for capturing microscopic surface geometry. The system extends the retrographic sensor [Johnson and Adelson 2009] to the microscopic domain, demonstrating spatial resolution as small as 2 microns. In contrast to existing microgeometry capture techniques, the system is not affected by the optical characteristics of the surface being measured---it captures the same geometry whether the object is matte, glossy, or transparent. In addition, the hardware design allows for a variety of form factors, including a hand-held device that can be used to capture high-resolution surface geometry in the field. We achieve these results with a combination of improved sensor materials, illumination design, and reconstruction algorithm, as compared to the original sensor of Johnson and Adelson [2009].National Science Foundation (U.S.) (Grant 0739255)National Institutes of Health (U.S.) (Contract 1-R01-EY019292-01
Critical Discussion of Balancing Corporate Performance and Conformance
This paper tries to ask what are the facts and truths and never let the flow of the research go to what we wish to believe. The aim is to identify how a company is able to balance performance and conformance in a sufficient way and learn from cases like Enron in 2001 and Worldcom in 2005 in order to teach those companies about record financial documentations to stay away from being charged by th
Novel Survivin Inhibitor for Suppressing Pancreatic Cancer Cells Growth via Downregulating Sp1 and Sp3 Transcription Factors
Background/Aims: Targeting survivin, an anti-apoptotic protein and mitotic regulator, is considered as an effective therapeutic option for pancreatic cancer (PaCa). Tolfenamic acid (TA) showed anti-cancer activity in pre-clinical studies. A recent discovery demonstrated a copper(II) complex of TA (Cu-TA) can result in higher activity. In this study, the ability of Cu-TA to inhibit survivin and its transcription factors, Specificity protein (Sp) 1 and 3 in PaCa cell lines and tumor growth in mouse xenograft model were evaluated. Methods: Cell growth inhibition was measured in MIA PaCa-2 and Panc1 cells for 2 days using CellTiter-Glo kit. Sp1, Sp3 and survivin expression (by Western blot and qPCR), apoptotic cells and cell cycle phase distribution (by flow cytometry) were evaluated. A pilot study was performed using athymic nude mice [treated with vehicle/Cu-TA (25 or 50 mg/kg) 3 times/week for 4 weeks. Results: The IC50 value for Cu-TA was about half than TA.Both agents repressed the protein expression of Sp1/Sp3/survivin, Cu-TA was more effective than TA. Especially effect on survivin inhibition was 5.2 (MIA PaCa-2) or 6.4 (Panc1) fold higher and mRNA expression of only survivin was decreased. Apoptotic cells increased with Cu-TA treatment in both cell lines, while Panc1 showed both effect on apoptosis and cell cycle (G2/M) arrest. Cu-TA decreased the tumor growth in mouse xenografts (25 mg/kg: 48%; 50 mg/kg: 68%). Additionally, there was no change observed in mice body weights, indicating no overt toxicity was occurring. Conclusion: These results show that Cu-TA can serve as an effective survivin inhibitor for inhibiting PaCa cell growth
Synthesis, characterization, DNA binding, topoisomerase inhibition, and apoptosis induction studies of a novel cobalt(III) complex with a thiosemicarbazone ligand
In this study, 9-anthraldehyde-N(4)-methylthiosemicarbazone (MeATSC) 1 and [Co(phen)(OCO)]Cl·6HO 2 (where phen = 1,10-phenanthroline) were synthesized. [Co(phen)(OCO)]Cl·6HO 2 was used to produce anhydrous [Co(phen)(HO)](NO)3. Subsequently, anhydrous [Co(phen)(HO)](NO)3 was reacted with MeATSC 1 to produce [Co(phen)(MeATSC)](NO)·1.5HO·CHOH 4. The ligand, MeATSC 1 and all complexes were characterized by elemental analysis, FT IR, UV-visible, and multinuclear NMR (H, C, and Co) spectroscopy, along with HRMS, and conductivity measurements, where appropriate. Interactions of MeATSC 1 and complex 4 with calf thymus DNA (ctDNA) were investigated by carrying out UV-visible spectrophotometric studies. UV-visible spectrophotometric studies revealed weak interactions between ctDNA and the analytes, MeATSC 1 and complex 4 (K = 8.1 × 10 and 1.6 × 10 M, respectively). Topoisomerase inhibition assays and cleavage studies proved that complex 4 was an efficient catalytic inhibitor of human topoisomerases I and IIα. Based upon the results obtained from the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay on 4T1-luc metastatic mammary breast cancer cells (IC = 34.4 ± 5.2 μM when compared to IC = 13.75 ± 1.08 μM for the control, cisplatin), further investigations into the molecular events initiated by exposure to complex 4 were investigated. Studies have shown that complex 4 activated both the apoptotic and autophagic signaling pathways in addition to causing dissipation of the mitochondrial membrane potential (ΔΨ). Furthermore, activation of cysteine-aspartic proteases3 (caspase 3) in a time- and concentration-dependent manner coupled with the ΔΨ, studies implicated the intrinsic apoptotic pathway as the major regulator of cell death mechanism
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