1,855 research outputs found
Taxation of risky investment and paradoxical investor behavior
Under uncertainty and irreversibility, real option-based models are widely accepted for assessing investment projects. So far the existing post-tax analyses do not provide a general analytical description of investor reactions towards profit tax rate changes. This paper sets out to fill part of the void. We implement a simple tax system and focus on risky capital market investment and an option to wait. Taxes affect risk-free and risky capital market investment asymmetrically and hence cause distortions. We analytically identify a set of neutral tax rates (tax regimes) that preserve the critical post-tax investment threshold in case of tax rate changes as well as general normal and paradoxical settings. Unlike for other tax paradoxa neither depreciation rules nor loss offset restrictions are responsible for the observed paradoxical reaction. Identifying normal and paradoxical tax regimes can be regarded as a first step to a generalized description of tax effects under uncertainty, both for individual project evaluation as well as for understanding tax effects on an aggregate level. --investment decision,real options,tax paradox,uncertainty
Developing a low-cost beer dispensing robotic system for the service industry
As the prices of commercially available electronic and mechanical components decrease, manufacturers such as Devantech and Revolution Education have made encoded motor controller systems and microcontrollers very accessible to engineers and designers. This has made it possible to design sophisticated robotic and mechatronic systems very rapidly and at relatively low cost. A recent project in the Autonomous Systems Lab at Middlesex University, UK was to design and build a small, automated, robotic bartender based around the 5 litre Heineken 'Draughtkeg' system, which is capable of patrolling a bar and dispensing beer when signalled to by a customer. Because the system was designed as a commercial product, design constraints focused on keeping the build cost down, and so electronic components were sourced from outside companies and interfaced with a bespoke chassis and custom mechanical parts designed and manufactured on site at the University. All the programming was conducted using the proprietary BASIC language, which is freely available from the PicAXE supplier at no cost. This paper will discuss the restrictions involved in building a robot chassis around 'off-theshelf' components, and the issues arising from making the human-machine interaction intuitive whilst only using low-cost ultrasonic sensors. Programming issues will also be discussed, such as the control of accuracy when interfacing a PicAXE microcontroller with a Devantech MD25 Motor Controller board. Public live testing of the system was conducted at the Kinetica Art Fair 2010 event in London and has since been picked up by websites such as Engadget.com and many others. Feedback on the system will be described, as well as the refinements made as a result of these test
The multimodal edge of human aerobotic interaction
This paper presents the idea of a multimodal human aerobotic interaction. An overview of the aerobotic system and its application is given. The joystick-based controller interface and its limitations is discussed. Two techniques are suggested as emerging alternatives to the joystick-based controller interface used in human aerobotic interaction. The first technique is a multimodal combination of speech, gaze, gesture, and other non-verbal cues already used in regular human-humaninteraction. The second is telepathic interaction via brain computer interfaces. The potential limitations of these alternatives is highlighted, and the considerations for further works are presented
Gene expression in periodontal tissues following treatment
<p>Abstract</p> <p>Background</p> <p>In periodontitis, treatment aimed at controlling the periodontal biofilm infection results in a resolution of the clinical and histological signs of inflammation. Although the cell types found in periodontal tissues following treatment have been well described, information on gene expression is limited to few candidate genes. Therefore, the aim of the study was to determine the expression profiles of immune and inflammatory genes in periodontal tissues from sites with severe chronic periodontitis following periodontal therapy in order to identify genes involved in tissue homeostasis.</p> <p>Gingival biopsies from 12 patients with severe chronic periodontitis were taken six to eight weeks following non-surgical periodontal therapy, and from 11 healthy controls. As internal standard, RNA of an immortalized human keratinocyte line (HaCaT) was used. Total RNA was subjected to gene expression profiling using a commercially available microarray system focusing on inflammation-related genes. Post-hoc confirmation of selected genes was done by Realtime-PCR.</p> <p>Results</p> <p>Out of the 136 genes analyzed, the 5% most strongly expressed genes compared to healthy controls were Interleukin-12A (IL-12A), Versican (CSPG-2), Matrixmetalloproteinase-1 (MMP-1), Down syndrome critical region protein-1 (DSCR-1), Macrophage inflammatory protein-2β (Cxcl-3), Inhibitor of apoptosis protein-1 (BIRC-1), Cluster of differentiation antigen 38 (CD38), Regulator of G-protein signalling-1 (RGS-1), and Finkel-Biskis-Jinkins murine osteosarcoma virus oncogene (C-FOS); the 5% least strongly expressed genes were Receptor-interacting Serine/Threonine Kinase-2 (RIP-2), Complement component 3 (C3), Prostaglandin-endoperoxide synthase-2 (COX-2), Interleukin-8 (IL-8), Endothelin-1 (EDN-1), Plasminogen activator inhibitor type-2 (PAI-2), Matrix-metalloproteinase-14 (MMP-14), and Interferon regulating factor-7 (IRF-7).</p> <p>Conclusion</p> <p>Gene expression profiles found in periodontal tissues following therapy indicate activation of pathways that regulate tissue damage and repair.</p
Brief Note Surface Charge Determination of Proteus Mirabilis Exposed to Carbenicillin
Author Institution: Division of Infectious Diseases, Department of Medicine, The Ohio State University College of Medicin
Investigating the use of unmanned plant machinery on construction sites
The UK Construction Sector has been estimated to contribute 8% of the UK’s GDP [1]. The worldwide recession has forced construction companies to introduce and adopt cost saving measures to increase productivity. Several robotic building systems are in development for the Construction Sector such as the PERI’s Automatic Climbing System [2] and Brokk’s remote-controlled demolition machines [3], but there has been little implementation on live sites. Construction sites by their very nature are dynamically changing environments, so if human input was removed entirely, a robot would need a high level of awareness of the current state of the building project in order to navigate and carry out its task
Novel Statistical Methods in Conjoint Analysis and Padé Approximation of the Profile Likelihood
This thesis addresses two topics in statistics that rely on the likelihood function for statistical inference. These topics include novel statistical research in conjoint analysis and a method to approximate the profile likelihood and create approximate profile likelihood confidence intervals.
After introducing choice-based conjoint analysis, we introduce a method to empirically assess and compare different conjoint analysis design strategies. A key feature of this method of comparison is that it makes very few assumptions about the data-generating process (essentially just that the respondents answer the surveys independently of one another) while remaining statistically valid; in particular, the respondents are not assumed to use the multinomial logit model.
We then turn to the statistical analysis of conjoint analysis survey results. We introduce a method to plot in two-dimensional space the heterogeneity in preferences across the respondents as inferred from the conjoint analysis survey results that can be used for visualization as well as mixture model assessment. We also introduce a novel method to accurately infer the number of natural clusters in preferences across the respondents. This method is shown in simulation studies to give more accurate results than latent class segmentation with AIC and BIC. We additionally suggest regressing estimated respondent preferences on their demographic variables as a strategy for hypothesis generation and model building.
We show that the profile likelihood can be well approximated near the maximum likelihood estimate by the [2,2] Padé approximant. This approximation is shown to be better than that provided by a second-order Taylor series approximation. However, like a second-order Taylor series approximation, it can be used to construct a confidence interval with endpoints found using the quadratic formula. The resulting confidence interval is similar to a profile likelihood interval but with computation time similar to that of a Wald interval
Development and characterization of an in vitro system of the human retina using cultured cell lines
Background: Previously developed in vitro cultures of the human retina have been solo or dual cell cultures. We developed a triple-cell culture in vitro model utilizing a membrane system to produce a better representation of a functional and morphological human retina. Methods: Retinal microvascular endothelial cells (HRMVEC/ACBRI181, Cell systems), retinal pigment epithelium cells (RPE/ARPE-19, ATCC) and Müller glial cells (MIO-M1, UCL) were grown in a triple-culture. Our optimized triple-culture media contained a mix of specific endothelial medium and high glucose Dulbecco's Modified Eagle's medium (DMEM), where all three layers were viable for up to 5 days. Co-culture effect on morphological changes (cell staining) and gene expression of functional genes (pigment epithelial derived factor (PEDF) and vascular endothelial growth factor (VEGF)) were measured from RNA via real time PCR. Expression of tight junction protein 1 (TJP1) was measured in RNA isolated from ARPE-19s, to assess barrier stability. Results: The triple-culture promotes certain cell functionality through up-regulation of TJP1, increasing PEDF and decreasing VEGF expression highlighting its importance for the assessment of disease mechanisms distinct from a solo culture which would not allow the true effect of the native microenvironment to be elucidated. Conclusion: This model's novelty and reliability allows for the assessment of singular cellular function within the retinal microenvironment and overall assessment of retinal health, whilst eliminating the requirement of animal-based models
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