Buying into the Bypass: Allowing Trucks to pay to use the Ramp Meter Bypasses

People make their route choices based on the delays they experience but not on the delays they impose on others. Moreover different travelers have different values of time. Road Pricing can be seen as the means to optimize the use of a roadway by charging each traveler the cost he imposes on others. This paper analyzes the opening of an HOV ramp meter bypass to trucks that pay a toll. Trucks are similar to HOV as both have a higher value of time than a single occupant car. Thus, by saving time for these vehicles the system stands to gain. The toll to be set was estimated under three scenarios ­ user benefit maximization, profit maximization and system benefit maximization. A queue was simulated, and based on the decision criteria the optimal toll was determined. It is found that to maximize the system welfare, the high Value of Time vehicles like trucks should be allowed to use the bypass for free, but that raises some equity and operational issues. However a toll that allows trucks to use the bypass improves the welfare over simply prohibiting the trucks from the bypass.Trucks, HOV, Ramp Meter, Pricing .

Freeway Origin Destination Matrices: Not as Simple as They Seem

Travel demand can be elegantly represented using an Origin-Destination (OD) matrix. The link counts observed on the network are produced by the underlying travel demand. One could use these counts to reconstruct the OD matrix. An offline approach to estimate a static OD matrix over the peak period for freeway sections using these counts is proposed in this research. Almost all the offline methods use linear models to approximate the relationship between the on-ramp and off-ramp counts. Previous work indicates that the use of a traffic flow model embedded in a search routine performs better than these linear models. In this research that approach is enhanced using a microscopic traffic simulator, AIMSUN, and a gradient based optimization routine, MINOS, interfaced to estimate an OD matrix. This approach is an application of the Prediction Error Minimization (PEM) method. The problem is non-linear and non-smooth, and the optimization routine finds multiple local minima, but cannot guarantee a global minima. However, with a number of starting seed matrices, an OD matrix with a good fit in terms of reproducing traffic counts can be estimated. The dominance of the mainline counts in the OD estimation and an identifiability issue is indicated from the experiments. The quality of the estimates improves as the specification error, introduced due to the discrepancy between the traffic flow model and the real world process that generates the on-ramp and off-ramp counts, reduces.travel demand, OD estimation, simulation, optimization

Communication and control in an integrated manufacturing system

Typically, components in a manufacturing system are all centrally controlled. Due to possible communication bottlenecking, unreliability, and inflexibility caused by using a centralized controller, a new concept of system integration called an Integrated Multi-Robot System (IMRS) was developed. The IMRS can be viewed as a distributed real time system. Some of the current research issues being examined to extend the framework of the IMRS to meet its performance goals are presented. These issues include the use of communication coprocessors to enhance performance, the distribution of tasks and the methods of providing fault tolerance in the IMRS. An application example of real time collision detection, as it relates to the IMRS concept, is also presented and discussed

Antibiotics to improve recovery following tonsillectomy: a systematic review.

OBJECTIVE: To determine if antibiotics improve recovery following tonsillectomy. STUDY DESIGN: DATA SOURCES: Electronic databases Medline, Embase, and Cochrane Controlled Trials Register were searched using relevant search terms. Additional trials, if any, were retrieved by searching the references from all identified trials, reviews, correspondences, editorials, and conference proceedings. No language restriction was applied. STUDY SELECTION: Systematic review of trials in which antibiotic was administered as a study medication intraoperatively and/or postoperatively, in children or adults undergoing tonsillectomy or adenotonsillectomy. Only randomized, placebo-controlled, double-blind trials attaining preset quality scores were included. Outcomes analyzed: 1) pain, need for analgesia, fever, halitosis, and return to normal diet and activities; 2) secondary hemorrhage using 2 parameters-significant hemorrhage (ie, warranting readmission, blood transfusion, or return to theatre for hemostasis) and total hemorrhage; and 3) adverse events. RESULTS: Five trials met the eligibility criteria. Antibiotics significantly reduced the number of subjects manifesting fever (relative risk [RR]: 0.62, 95% confidence interval [CI]: 0.45, 0.85) and duration of halitosis (-1.94 [-3.57, -0.30] days), and marginally reduced the time taken to resume normal activity (-0.63 [-1.12, -0.14] days), but had no significant effect in reducing pain scores (-0.01 [-0.60, 0.57]) or need for analgesia. Similarly, there was no significant difference in the time taken to resume normal diet or incidence of significant and total hemorrhage, although data was underpowered to detect differences for these outcomes. In the antibiotic group 4 patients developed an adverse reaction (3 cases of rash and 1 case of oropharyngeal candidiasis), while in the control group 1 patient had an adverse reaction (rash). The RR of antibiotic-related adverse events was 2.45 (0.45, 13.31). CONCLUSION: Antibiotics appear to be effective in reducing some, but not all, morbid outcomes following tonsillectomy, and may increase the risk of adverse events. Further trials are needed to better define the role of antibiotics in facilitating post-tonsillectomy recovery. EBM RATING: A-1a

Autocrine prolactin: an emerging market for homegrown (prolactin) despite the imports

Prolactin (PRL) is a peptide hormone that is produced by the pituitary gland and is known to regulate lactogenic differentiation. There is a significant body of evidence that points to autocrine production of prolactin and activation of an autocrine/paracrine signaling pathway to regulate cell proliferation and migration and inhibition of cell death. This perspective highlights the recent study in the October 1, 2012, issue of Genes & Development by Chen and colleagues (pp. 2154-2168) that describes a mechanism for autocrine prolactin production and places the finding in the context of a role for prolactin in breast development and cancer

A New Tumor Suppressor That Regulates Tissue Architecture

Pathologists use loss of normal tissue architecture as a key criterion to identify and categorize disease states. Epithelia in all glandular structures in vivo have a characteristic organization where they line a central lumen and are involved in absorptive and/or secretory functions. Under some physiological conditions—such as pregnancy, wound healing, and the periodic tissue remodeling that occurs in tissues such as colon—there is a significant increase in the rate of cell proliferation. Although the proliferation rate in these physiological conditions is higher than that seen under disease states, the overall tissue size and structure are maintained. Such maintenance of size/structure occurs because the increased proliferation is tightly coupled with tissue morphogenesis programs, resulting in remodeling of normal tissue architecture

On the origin of the Epps effect

The Epps effect, the decrease of correlations between stock returns for short time windows, was traced back to the trading asynchronicity and to the occasional lead-lag relation between the prices. We study pairs of stocks where the latter is negligible and confirm the importance of asynchronicity but point out that alone these aspects are insufficient to give account for the whole effect.Comment: 7 pages, 4 figures; to appear in the Proceedings of Econophysics Colloquium 2006 References adde

International Outsourcing in the Information Technology Industry: Trends and Implications

This paper reviews trends in the use of international outsourcing in the Information Technology (IT) industry and explores implications for the U.S. workforce. Workforce employment projections and the trend for globalization in the IT industry are analyzed. An analogy is developed between current trends in IT workforce and the globalization of the auto industry during the latter part of the 20th century. The conclusion is that recent dips in U.S. IT employment may represent more than a transitory reflection of current economic conditions. International IT providers may be capturing a permanent share of U.S. IT expenditures and thus reducing the long term need for U.S. IT employment. IT industry and educational institutions need to plan accordingly for these new global workforce realities

ErbB receptors and cell polarity: New pathways and paradigms for understanding cell migration and invasion

The ErbB family of receptor tyrosine kinases is involved in initiation and progression of a number of human cancers, and receptor activation or overexpression correlates with poor patient survival. Research over the past two decades has elucidated the molecular mechanisms underlying ErbB-induced tumorigenesis, which has resulted in the development of effective targeted therapies. ErbB-induced signal transduction cascades regulate a wide variety of cell processes, including cell proliferation, apoptosis, cell polarity, migration and invasion. Within tumors, disruption of these core processes, through cooperative oncogenic lesions, results in aggressive, metastatic disease. This review will focus on the ErbB signaling networks that regulate migration and invasion and identify a potential role for cell polarity pathways during cancer progression