A bi-level programming approach for trip matrix estimation and traffic control problems with stochastic user equilibrium link flows

This paper deals with two mathematically similar problems in transport network analysis: trip matrix estimation and traffic signal optimisation on congested road networks. These two problems are formulated as bi-level programming problems with stochastic user equilibrium assignment as the second-level programming problem. We differentiate two types of solutions in the combined matrix estimation and stochastic user equilibrium assignment problem (or, the combined signal optimisation and stochastic user equilibrium assignment problem): one is the solution to the bi-level programming problem and the other the mutually consistent solution where the two sub-problems in the combined problem are solved simultaneously. In this paper, we shall concentrate on the bi-level programming approach although we shall also consider mutually consistent solutions so as to contrast the two types of solutions. The purpose of the paper is to present a solution algorithm for the two bi-level programming problems and to test the algorithm on several networks

Inhibition of APC Cdh1 Activity by Cdh1/Acm1/Bmh1 Ternary Complex Formation

The anaphase-promoting complex (APC) is an essential E3 ubiquitin ligase responsible for catalyzing proteolysis of key regulatory proteins in the cell cycle. Cdh1 is a co-activator of the APC aiding in the onset and maintenance of G(1) phase, whereas phosphorylation of Cdh1 at the end of G(1) phase by cyclin-dependent kinases assists in the inactivation of APC(Cdh1). Here, we suggest additional components are involved in the inactivation of APC(Cdh1) independent of Cdh1 phosphorylation. We have identified proteins known as Acm1 and Bmh1, which bind and form a ternary complex with Cdh1. The presence of phosphorylated Acm1 is critical for the ternary complex formation, and Acm1 is predominantly expressed in S phase when APC(Cdh1) is inactive. The assembly of the ternary complex inhibits ubiquitination of Clb2 in vitro by blocking the interaction of Cdh1 with Clb2. In vivo, lethality caused by overexpression of constitutively active Cdh1 is rescued by overexpression of Acm1. Partially phosphorylated Cdh1 in the absence of ACM1 still binds to and activates the APC. However, the addition of Acm1 decreases Clb2 ubiquitination when using either phosphorylated or nonphosphorylated Cdh1. Taken together, our results suggest an additional inactivation mechanism exists for APC(Cdh1) that is independent of Cdh1 phosphorylation

Evaluation of Average and Maximum Heart Rate of Wrist-worn Wearable Technology Devices During Trail Running

It has been estimated that there are 20 million people who participate in trail running, and these numbers are expected to increase by 15% each year. Our laboratory group has conducted studies on the validity of wearable technology watches and heart rate (HR) during trail running. The previous generation devices were mostly inaccurate, and a limitation was that reliability was not measured. PURPOSE: To determine both validity and reliability in newer models of wearable devices during trail running. METHODS: Seventeen participants (F = 7) ran on the Thunderbird Gardens Lightning Switch trail in Cedar City, UT. Demographic characteristics: Age = 25 (9) years (mean [standard deviation]), ht = 168 (9) cm, mass = 72 (14) kg. Two Garmin Instincts and two Polar Vantage M2s were evaluated, along with the Polar H10 chest strap as the criterion measure. Participants ran out on the trail for 10-minutes, and then returned to the trailhead. Maximum HR and average HR were measured during the run. Data were analyzed for validity (Mean Absolute Percent Error [MAPE] and Lin’s Concordance [CCC]) and reliability (Coefficient of Variation [CV] and Intraclass Correlation Coefficient [ICC]). Predetermined thresholds were: MAPE0.70, CV0.70. RESULTS: The Garmin Instinct met the threshold for both reliability tests for average and maximum HR (see table). The Garmin Instinct and Polar Vantage met the threshold for both validity tests for maximum HR. CONCLUSION: In order for a device to be considered valid, it must meet the predetermined thresholds for both validity and reliability. These results indicate that only the Garmin Instinct is valid and reliable, but only for measuring maximum HR. This is challenging for those who wish to track their HR while trail running, because neither of the studied devices were valid and reliable for maximum and average HR

Keeping the Board in the Dark: CEO Compensation and Entrenchment

We study a model in which a CEO can entrench himself by hiding information from the board that would allow the board to conclude that he should be replaced. Assuming that even diligent monitoring by the board cannot fully overcome the information asymmetry visà- vis the CEO, we ask if there is a role for CEO compensation to mitigate the inefficiency. Our analysis points to a novel argument for high-powered, non-linear CEO compensation such as bonus pay or stock options. By shifting the CEO’s compensation into states where the firm’s value is highest, a high-powered compensation scheme makes it as unattractive as possible for the CEO to entrench himself when he expects that the firm’s future value under his management and strategy is low. This, in turn, minimizes the severance pay needed to induce the CEO not to entrench himself, thereby minimizing the CEO’s informational rents. Amongst other things, our model suggests how deregulation and technological changes in the 1980s and 1990s might have contributed to the rise in CEO pay and turnover over the same period

Characterisation and Carriage Ratio of Clostridium difficile Strains Isolated from a Community-Dwelling Elderly Population in the United Kingdom

Background Community-associated Clostridium difficile infection (CDI) appears to be an increasing problem. Reported carriage rates by C.difficile are debatable with suggestions that primary asymptomatic carriage is associated with decreased risk of subsequent diarrhoea. However, knowledge of potential reservoirs and intestinal carriage rates in the community, particularly in the elderly, the most susceptible group, is limited. We have determined the presence of C.difficile in the faeces of a healthy elderly cohort living outside of long-term care facilities (LCFs) in the United Kingdom. Methods Faecal samples from 149 community-based healthy elderly volunteers (median age 81 years) were screened for C.difficile using direct (Brazier's CCEY) and enrichment (Cooked Meat broth) culture methods and a glutamate dehydrogenase (GDH) immunoassay. Isolates were PCR-ribotyped and analysed for toxin production and the presence of toxin genes. Results Of 149 faecal samples submitted, six (4%) were found to contain C.difficile. One particular sample was positive by both the GDH immunoassay and direct culture, and concurrently produced two distinct strain types: one toxigenic and the other non-toxigenic. The other five samples were only positive by enrichment culture method. Overall, four C.difficile isolates were non-toxigenic (PCR-ribotypes 009, 026 (n = 2) and 039), while three were toxigenic (PCR-ribotypes 003, 005 and 106). All individuals who had a positive culture were symptom-free and none of them had a history of CDI and/or antibiotics use in the 3 month period preceding recruitment. Conclusions To our knowledge, this is the first study of the presence of C.difficile in healthy elderly community-dwelling individuals residing outside of LCFs. The observed carriage rate is lower than that reported for individuals in LCFs and interestingly no individual carried the common epidemic strain PCR-ribotype 027 (NAP1/BI). Further follow-up of asymptomatic carriers in the community, is required to evaluate host susceptibility to CDI and identify dynamic changes in the host and microbial environment that are associated with pathogenicity

Light Microsopy Module, International Space Station Premier Automated Microscope

The Light Microscopy Module (LMM) was launched to the International Space Station (ISS) in 2009 and began science operations in 2010. It continues to support Physical and Biological scientific research on ISS. During 2015, if all goes as planned, five experiments will be completed: [1] Advanced Colloids Experiments with a manual sample base -3 (ACE-M-3), [2] the Advanced Colloids Experiment with a Heated Base -1 (ACE-H-1), [3] (ACE-H-2), [4] the Advanced Plant Experiment -03 (APEX-03), and [5] the Microchannel Diffusion Experiment (MDE). Preliminary results, along with an overview of present and future LMM capabilities will be presented; this includes details on the planned data imaging processing and storage system, along with the confocal upgrade to the core microscope. [1] New York University: Paul Chaikin, Andrew Hollingsworth, and Stefano Sacanna, [2] University of Pennsylvania: Arjun Yodh and Matthew Gratale, [3] a consortium of universities from the State of Kentucky working through the Experimental Program to Stimulate Competitive Research (EPSCoR): Stuart Williams, Gerold Willing, Hemali Rathnayake, et al., [4] from the University of Florida and CASIS: Anna-Lisa Paul and Rob Ferl, and [5] from the Methodist Hospital Research Institute from CASIS: Alessandro Grattoni and Giancarlo Canavese

A multicentre randomised controlled trial evaluating lactobacilli and bifidobacteria in the prevention of antibiotic-associated diarrhoea in older people admitted to hospital: the PLACIDE study protocol

<p>Abstract</p> <p>Background</p> <p>Antibiotic associated diarrhoea complicates 5–39% of courses of antibiotic treatment. Major risk factors are increased age and admission to hospital. Of particular importance is <it>C. difficile</it> associated diarrhoea which occurs in about 4% of antibiotic courses and may result in severe illness, death and high healthcare costs. The emergence of the more virulent 027 strain of <it>C. difficile</it> has further heightened concerns. Probiotics may prevent antibiotic associated diarrhoea by several mechanisms including colonization resistance through maintaining a healthy gut flora.</p> <p>Methods</p> <p>This study aims to test the hypothesis that administration of a probiotic comprising two strains of lactobacilli and two strains of bifidobacteria alongside antibiotic treatment prevents antibiotic associated diarrhoea. We have designed a prospective, parallel group trial where people aged 65 years or more admitted to hospital and receiving one or more antibiotics are randomly allocated to receive either one capsule of the probiotic or a matching placebo daily for 21 days. The primary outcomes are the frequency of antibiotic associated and <it>C. difficile</it> diarrhoea during 8–12 weeks follow-up. To directly inform routine clinical practice, we will recruit a sufficient number of patients to demonstrate a 50% reduction in the frequency of <it>C. difficile</it> diarrhoea with a power of 80%. To maximize the generalizability of our findings and in view of the well-established safety record of probiotics, we will recruit a broad range of medical and surgical in-patients from two different health regions within the UK.</p> <p>Discussion</p> <p>Antibiotic associated diarrhoea constitutes a significant health burden. In particular, current measures to prevent and control <it>C. difficile</it> diarrhoea are expensive and disrupt clinical care. This trial may have considerable significance for the prevention of antibiotic associated diarrhoea in hospitals.</p> <p>Trial registration</p> <p>International Standard Randomised Controlled Trial Number Register ISRCTN70017204.</p

A method for the isolation of human gastric mucous epithelial cells for primary cell culture: A comparison of biopsy vs surgical tissue

We have developed a method for the isolation and growth of normal human gastric mucous epithelial cells using biopsies or surgically resected tissues as the source of the cells. The attachment and growth of cells were dependent upon: (1) cell planting density, ∼50,000 cells/cm 2 ; (2) extracellular matrix (fibronectin); and (3) and the use of a porous filter. In all experiments we found better cells attachment and growth of human gastric mucous cells isolated from surgical specimens compared with those gastric mucous cells isolated from gastric biopsies. The initial cell viability (as measured by Trypan-blue) was the same in both populations of gastric mucous epithelial cells isolated from either gastric biopsies or surgical specimens. After 4–5 days in culture one could detect various amounts of mucin in all the cells using either periodic acid Schiff (PAS) staining or a specific anti-mucin antibody. A similar pattern of much straining was also found in primary cultures of guinea pig gastric mucous epithelial cells. Immunohistochemical staining for chief cells (anti-pepsinogen) or parietal cells (anti-H + /K + ATPasc) in the gastric mucous cuboidal-like epithelial cells with tight junctions, desmosomes,short microvilli, a filamentous terminal web, mucous granules, and basal lamina-like structure. We could not detect the presence of fibroblasts during the 7–9 days that the primary cells were in culture. This cell culture method will prove useful in the isolation of normal human gastric mucous epithelial cells for in vitro studies of gastric mucosal injury and repair.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43235/1/11022_2004_Article_BF00127904.pd