Regulation of rubisco in purple nonsulfur bacteria

Includes bibliographical references.Rubisco is an enzyme that catalyzes the first reaction in the Calvin Cycle in photosynthesis. Since it is a poor catalyst, research has attempted to improve the rate at which it fixes carbon because this could in turn increase crop yields, in plants, Rubisco is regulated by light but the evolution of regulatory proteins and mechanisms is unknown. By studying Rubisco activity in photosynthetic bacteria, the origins of its regulation can be explored, we grew purple nonsulfur bacteria on two main substrates and used a culture grown in constant light conditions as a control. The experimental culture was grown in cyclic light and dark conditions to imitate the natural environment. Enzyme assays were performed on samples taken from both the experimental culture during both the light and dark parts of the cycle, we then analyzed the assay in terms of how much carbon was fixed per milligram of protein per hour, we found no evidence of inhibition of Rubisco in the dark. However, we conducted experiments in which we found a set of variables that gave optimal Rubisco activity.B.S. (Bachelor of Science

A novel modeling approach for express package carrier planning

Express package carrier networks have large numbers of heavily-interconnected and tightly-constrained resources, making the planning process difficult. A decision made in one area of the network can impact virtually any other area as well. Mathematical programming therefore seems like a logical approach to solving such problems, taking into account all of these interactions. The tight time windows and nonlinear cost functions of these systems, however, often make traditional approaches such as multicommodity flow formulations intractable. This is due to both the large number of constraints and the weakness of the linear programming (LP) relaxations arising in these formulations. To overcome these obstacles, we propose a model in which variables represent combinations of loads and their corresponding routings, rather than assigning individual loads to individual arcs in the network. In doing so, we incorporate much of the problem complexity implicitly within the variable definition, rather than explicitly within the constraints. This approach enables us to linearize the cost structure, strengthen the LP relaxation of the formulation, and drastically reduce the number of constraints. In addition, it greatly facilitates the inclusion of other stages of the (typically decomposed) planning process. We show how the use of templates, in place of traditional delayed column generation, allows us to identify promising candidate variables, ensuring high-quality solutions in reasonable run times while also enabling the inclusion of additional operational considerations that would be difficult if not impossible to capture in a traditional approach. Computational results are presented using data from a major international package carrier. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60965/1/20310_ftp.pd

A Writer, an Editor, an Instructor, and an Alumna Walk into the Writing Center

As the writing center director, I believe our professional tutors provide valuable expert perspectives to student writers. They also help me mentor the peer tutors and push me to reevaluate our practices. They add staffing stability to the center (whose peer tutors never stay for more than three years). Finally, these trusted writing experts professionalize the writing center’s status among administration, faculty, and students. In the following paragraphs, Amy, Ellen, Chris, and Lindsey illustrate the rich variety of skills and perspectives professional writing tutors can contribute to a writing centerUniversity Writing Cente

An Implicit Optimization Approach for Survivable Network Design

We consider the problem of designing a network of minimum cost while satisfying a prescribed survivability criterion. The survivability criterion requires that a feasible flow must still exists (i.e. all demands can be satisfied without violating arc capacities) even after the disruption of a subset of the network's arcs. Specifically, we consider the case in which a disruption (random or malicious) can destroy a subset of the arcs, with the cost of the disruption not to exceed a disruption budget. This problem takes the form of a tri-level, two-player game, in which the network operator designs (or augments) the network, then the attacker launches a disruption that destroys a subset of arcs, and then the network operator attempts to find a feasible flow over the residual network. We first show how this can be modeled as a two-stage stochastic program from the network operator's perspective, with each of the exponential number of potential attacks considered as a disruption scenario. We then reformulate this problem, via a Benders decomposition, to consider the recourse decisions implicitly, greatly reducing the number of variables but at the expense of an exponential increase in the number of constraints. We next develop a cut-generation based algorithm. Rather than \emph{explicitly} considering each disruption scenario to identify these Benders cuts, however, we develop a bi-level program and corresponding separation algorithm that enables us to \emph{implicitly} evaluate the exponential set of disruption scenarios. Our computational results demonstrate the efficacy of this approach

New Methods for Resolving Conflicting Requests with Examples from Medical Residency Scheduling

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138246/1/poms12728.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138246/2/poms12728-sup-0001-SupInfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138246/3/poms12728_am.pd

Utilization, Receptivity and Reactivity to Interactive Voice Response Daily Monitoring in Risky Drinking Smokers Who Are Motivated to Quit

INTRODUCTION Interactive Voice Response (IVR) technology has become an increasingly popular and valid method for collecting Ecological Momentary Assessment (EMA) data on a variety of health-risk behaviors, including daily alcohol use and cigarette smoking, and for stimulating behavior change. However, very little research has evaluated the parameters of IVR compliance and reactivity in respondents who may have greater problem severity than samples previously examined in published IVR studies. This study examined the prevalence and correlates of use, receptivity and reactivity to IVR monitoring in 77 untreated risky drinking smokers who were motivated to quit within the next 6 months. METHODS Respondents completed twice daily IVR assessments for 28 days and were re-assessed immediately after IVR to measure receptivity and reactivity to daily monitoring and six months post-baseline. RESULTS Mean compliance rate was 70.6%, with a morning rate of 72.4% and an evening compliance rate of 68.9% out of all possible surveys. IVR assessments of drinking and smoking were significantly associated with baseline paper-pencil reports of the same. African-American participants and those who reported more daily stressful events were more compliant. Between the baseline session and the 6-month follow-up, 68% of the sample reported engaging in some form of smoking behavior change (50% reduction in CPD, a quit attempt, past month continuous abstinence). Nearly 80% reported increased awareness of their behavior due to the IVR and 40% reported intentional behavior change from IVR monitoring. The odds of making a quit attempt at the 6-month follow-up were significantly higher among respondents who reported making purposeful changes to their smoking as a result of IVR monitoring (AOR=3.25, p\u3c0.05). CONCLUSIONS Reactivity was associated with behavior change outcomes. IVR may be a useful tool for motivating behavior change in smokers with alcohol-use problems

The architecture of convention hotels in the United States, 1940-1976

The convention hotel emerged as a distinct building type in the years of the Second World War and its aftermath. The earliest examples of convention hotels were distinguished from their pre-war counterparts by the design of their meeting facilities and the layout of public areas. In these projects, new techniques in architectural design were used only where they were critical to hotel operation. As the number of hotels increased in the fifties, competition for business required new approaches to design. For some hotel companies, the policy was to improve a hotel's capability for handling groups in order to attract sizable conventions to the property. In resort cities, hotel operators found that innovations in style and decor enhanced popular appeal, thereby increasing business. In the late fifties and early sixties, the participation of developers and corporations outside the hotel industry in building new properties brought about an increasing diversity. In the projects, design was based on potential profitability regardless of traditional hotel principles. At the same time, the inclusion of convention hotels in large-scale urban developments called for innovations in site planning and expansion of public amenities. While these hotels and their predecessors of the fifties rarely displayed architectural excellence, their contribution to guidelines for modern hotel design was critical to later, more spectacular developments of the building type. One project of the late sixties, the Hyatt Regency Atlanta, dramatically explored the potential of new approaches to hotel architecture. The astounding design of the public spaces, the integration of the hotel with surrounding development, and the hotel's subsequent popularity have served to transform this commercial building type into significant public architecture. The success of the. Atlanta Hyatt has led to a repetition of the concept by the hotel company, while inspiring new experiments by the architect. In the early seventies, a series of hotels of remarkable design opened in the United States. Their public appeal confirmed the value of good architecture to the successful operation of a hotel. Hotel professionals were forced to reconsider the necessary elements of hotel design, while architects were encouraged to re-examine the possibilities inherent in this commercial building type

Experiences of a commercial weight-loss programme after primary care referral: a qualitative study.

BACKGROUND: Referral to a commercial weight-loss programme is a cost-effective intervention that is already used within the NHS. Qualitative research suggests this community-based, non-medical intervention accords with participants' view of weight management as a lifestyle issue. AIM: To examine the ways in which participants' attitudes and beliefs about accessing a commercial weight management programme via their doctor relate to their weight-loss experience, and to understand how these contextual factors influence motivation and adherence to the intervention. DESIGN AND SETTING: A qualitative study embedded in a randomised controlled trial evaluating primary care referral to a commercial weight-loss programme in adults who are overweight or obese in England. The study took place from June-September 2013. METHOD: Twenty-nine participants (body mass index [BMI] ≥28 kg/m(2); age ≥18 years), who took part in the WRAP (Weight Loss Referrals for Adults in Primary Care) trial, were recruited at their 3-month assessment appointment to participate in a semi-structured interview about their experience of the intervention and weight management more generally. Interviews were audiorecorded, transcribed verbatim, and analysed inductively using a narrative approach. RESULTS: Although participants view the lifestyle-based, non-medical commercial programme as an appropriate intervention for weight management, the referral from the GP and subsequent clinical assessments frame their experience of the intervention as medically pertinent with clear health benefits. CONCLUSION: Referral by the GP and follow-up assessment appointments were integral to participant experiences of the intervention, and could be adapted for use in general practice potentially to augment treatment effects

An Optimal Algorithm for Integrating Printed Circuit Board Manufacturing Problems

Printed circuit boards appear in a wide array of products and thus their production is crucial to the contemporary electronics industry. A global approach to planning the complex and multi-stage production process is currently intractable. Nonetheless,significant improvements can be made by integrating closely related elements within the planning process. We focus here on the integration of two key problems -- product clustering and machine setup. In the product clustering problem, board types with similar component requirements are clustered together for assembly under a common configuration of the pick-and-place machine. In the machine setup problem, an optimal configuration of the pick-and-place machine is found for each of these clusters. In practice and in the literature, the product clustering and machine setup problems are typically solved sequentially. By instead solving the two problems simultaneously, we are able to find an optimal tradeoff between processing and setup times. We present the Integrated Clustering and Machine Setup model as a set partitioning problem. We describe a branch-and-price algorithm for solving this exponentially large problem. We introduce a rank-cluster-and-prune, a method for solving the imbedded pricing problems by combinatorial search, and conclude with computational results