Search

NP-complete problems such as the traveling salesman problem (TSP) play a prominent role in most advanced undergrad/graduate courses in discrete optimization modeling. Teaching such an important topic from a purely mathematical perspective without discussing specific applications may result in reduced student interest and motivation. The DeLand Crayon Company case introduces students to an application of the TSP to a practical production-planning scenario with realistic data. In crayon production, proper sequencing of colors in production can result in significant savings in total production time. The primary objective of the case is to provide students with hands-on experience in applying the TSP model. The case requires the students to consider variations of the basic model with the goal of encouraging them to think logically through the process of mathematical modeling and to consider the decision-making implications of their models. This case study can be used in undergraduate- and graduate-level courses in linear/integer programming or in production planning. It was implemented as part of a term project in a graduate operations research course with overwhelmingly positive feedback.

DeLand Crayon Company (DCC) is a large manufacturer of molded wax crayons. DCC sells three sizes of crayons, namely standard, large and jumbo. Standard-sized crayons, which account for most of the demand, include nine basic colors (red, blue, green, yellow, orange, violet, brown, black, and white), seven popular combination colors (red-orange, yellow-orange, yellow-green, red-violet, blue-green, blue-violet, and pink), 16 fluorescent colors, and four metallic colors. DCC also manufactures several specialty crayons, such as reduced length, hexagonal shaped, golden glitter, glow-in-the-dark, wipe-off, washable, and keno. Demand for non–standard-size crayons, fluorescent, and metallic-colored standard crayons and the specialty crayons is low and uneven, but DCC believes that they must be maintained to create the perception of a broad product line.

Unsustainable trade in wildlife products both legally and illegally is a leading cause of population declines and increased extinction risk in commercially valuable species. However due to the clandestine nature of illegal trade and paucity of overarching studies of legal trade our understanding on international trade networks is patchy. We develop a gravity–underreporting modelling framework to analyse and compare: (i) data on the legal trade in mammalian, avian and reptilian products from recorded by The Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) and (ii) to data on the seizures of illegal products entering the USA between 2004 and 2013. We find substantial differences in the factors driving legal trade for the 3 taxonomic groups considered, indicating different drivers for different product markets. Illegal imports for all groups were associated with increasing exporter GDP. We found higher probabilities of underreporting for avian and reptile products, and in general central Africa, central Asia, Eastern Europe and Pacific Island states showed higher underreporting than other regions, indicating the existence of complex trade networks and the potential for the laundering of illegal products through legal markets. Our results show the important regional and economic trends driving wildlife trade. Our new modelling framework can also help illuminate previously unseen aspects of illegal and legal wildlife trade, which can help with the implementation of interventions to curb the impact of trade on wild populations.

The “Building Capacity for Conservation in Southeast Asia” symposium was held at the 2015 Association for Tropical Biology and Conservation, Asia-Pacific Chapter meeting. The range of programs discussed fell into three categories: career development, project-specific activities and outreach, and delivering conservation information to diverse audiences. Though different approaches were used, we identified practices and methods which increased the meaning, relevance, and applicability of the messages provided. We found that delivering successful conservation education requires understanding conservation's place in society, developing a feeling of community among students, providing students with financial support, practical teaching, and crafting culturally appropriate messages.

A comprehensive case study to introduce students to several concepts from linear, integer, and goal programming in an integrative manner is presented. Starting with a relatively simple production planning decision problem, the case progressively incorporates generalizations to introduce various modeling principles. Each variation to the case enables the teacher to engage in insightful discussion into the nature of the optimal solutions; the effect on the optimum solution of changes to the objective function or to key constraints. The case article also describes several ways in which the case can be used, ranging from a comprehensive introduction to a concluding capstone case in an undergraduate or graduate course in linear programming. Case Teaching Note: Interested Instructors please see the Instructor Materials page for access to the restricted materials. To maintain the integrity and usefulness of cases published in ITE, unapproved distribution of the case teaching notes and other restricted materials to any other party is prohibited.

Human-wildlife conflict (HWC) is a conservation concern that increasingly threatens the continued existence of some of the world's most endangered species. With an increase in human population, urban sprawl and subsequent encroachment on wild land, human and wildlife interaction has become inevitable. In the majority of cases, this interaction results in a negative outcome for humans, wildlife or both. In China, these key elements, along with a decrease in wild prey species, have resulted in the expansion of HWC encounters, and the need for alleviating this conflict has become a conservation priority. Loss of human life, livestock and/or crops is most often the catalysts that fuel HWC. Techniques to alleviate conflict around the world have included preventative measures and mitigation techniques, such as financial compensation and other incentive programs. Both types of measures have had variable success. We review the current status of human-carnivore conflict management in China, and, drawing lessons from around the globe, we make recommendations for improving conservation management in China. For example, an increase in law enforcement in nature reserves is vital to reducing human disturbance in prime carnivore habitat, thereby reducing conflict encounters. Also, modifications to current wildlife compensation programs, so that they are linked with preventative measures, will ensure that moral hazards are avoided. Furthermore, investigating the potential for a community self-financed insurance scheme to fund compensation and increasing efforts to restore wild prey populations will improve the outcome for wildlife conservation. Ultimately, HWC management in China will greatly benefit from an integrative approach.

BackgroundCancer is one of the most common diseases that patients research on the Internet. The Commission on Cancer (CoC) recommended that Parkland Memorial Hospital (PMH) improve the oncology services website. PMH is Dallas County’s public health care facility, serving a largely uninsured, minority population. Most research regarding patient Internet use has been conducted in insured, Caucasian populations, raising concerns that the needs of PMH patients may not be extrapolated from available data. The PMH Cancer Committee, therefore, adopted a quality improvement initiative to understand patients’ Internet usage. ObjectiveThe objective of the study was to obtain and analyze data regarding patients’ Internet usage in order to make targeted improvements to the oncology services section of the institutional website. MethodsA task force developed an 11-question survey to ascertain what proportion of our patients have Internet access and use the Internet to obtain medical information as well as determine the specific information sought. Between April 2011 and August 2011, 300 surveys were administered to newly diagnosed cancer patients. Multivariate analyses were performed. ResultsOf 300 surveys, 291 were included. Minorities, primarily African-American and Hispanic, represented 78.0% (227/291) of patients. Only 37.1% (108/291) of patients had Internet access, most (256/291, 87.9%) having access at home. Younger patients more commonly had Internet access, with a mean age of 47 versus 58 years for those without (P

Understanding processes driving population declines and, ultimately, species loss in forest isolates has significant implications for the long-term maintenance of species diversity. We investigated a potential mechanism driving loss of plant species in small, medium, and large land-bridge islands in Lago Guri, a 4300-km2 hydroelectric impoundment in the State of Bolivar, Venezuela. Our hypothesis was that elevated Atta ( leaf-cutter ants) herbivory on small Guri islands, attributable to release from predation, could result in reduced sapling densities, with potentially negative effects on preferred plant species. We experimentally established Atta preferences among 43 common tree species. Vegetation plots on small, medium, and large land masses were examined for variation in density, size-class distribution, and representation of preferred and less preferred species of small stems. Densities of adult trees of preferred and less preferred species were compared between Atta colony foraging zones and control plots without active Atta colonies, and between foraging zones on the small islands and the large island. Small stem densities were significantly reduced on the small islands, especially in the sapling category (≥1 m tall

When you take a look at anything close-by, your brain computes the position of the object you see by solving a lanky triangle — namely the one formed with the object and your two eyes as its vertices. The brain may call other clues also into service while figuring out positions, especially when the lanky triangles prove far too lanky to afford trigonometric solutions with reasonable accuracy. These non-trigonometric alternatives can run into occasional pitfalls, though. Yet even the trigonometric highway isn’t always foolproof, either. We shall see in what follows that the resulting consequences can be as instructive as they are amusing.

Some time earlier1 we treated our readers to an exoteric narrative of special relativity’s kinematics in which we shunned the use of mathematical formulas. However, the simple and concise account presented then has left quite a few questions open, and we now present the promised sequel to supply the requisite answers.

Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis, with as yet undetermined incidence and prevalence in the general population. Our understanding of it continues to evolve. In the last few years, 2 separate subtypes have been identified: type 1 AIP has been recognised as the pancreatic manifestation of a multiorgan disease, named immunoglobulin G4 (IgG4)-related disease while type 2 AIP is a pancreas specific disorder not associated with IgG4. International criteria for the diagnosis of AIP have been defined: the HISORt criteria from the Mayo clinic, the Japan consensus criteria and, most recently, the international association of pancreatology “International Consensus Diagnostic Criteria”. Despite this, in clinical practice it can still be very difficult to confirm the diagnosis and differentiate AIP from a pancreatic cancer. There are no large studies into the long-term prognosis and management of relapses of AIP, and there is even less information at present regarding the Type 2 AIP subtype. Further studies are necessary to clarify the pathogenesis, treatment and long-term outcomes of this disease. Critically for clinicians, making the correct diagnosis and differentiating the disease from pancreatic cancer is of the utmost importance and the greatest challenge.

Declining biodiversity in protected areas in Laos is attributed to unsustainable exploitation of natural resources. At a basic level, an important need is to develop capacity in academic and professional training institutions to provide relevant training to conservation professionals. The paper (a) describes the capacity building approach undertaken to achieve this goal, (b) evaluates the effectiveness of the approach in building capacity for implementing conservation and (c) reviews implementation outcomes. Strong linkages between organizations implementing field conservation, professional training institutions, and relevant Government agencies are central to enhancing effectiveness of capacity building initiatives aimed at improving the practice of conservation. Protected area management technical capacity needs will need to directly influence curriculum design to insure both relevance and effectiveness of training in improving protected area management. Sustainability of capacity building initiatives is largely dependent on the level of interest and commitment by host-country institutions within a supportive Government policy framework in addition to engagement of organizations implementing conservation.

Falcon Die Casting Company (FDC) is an automotive parts manufacturer based in Ohio. FDC recently patented an innovative method of high volume die casting using traditional die casting machines. This patent was instrumental in FDC receiving a long term contract from a major automobile manufacturer for the bulk of its requirements for five key die cast items used in most of its automobiles. The customer provides FDC with an indication of the possible demand for the next 12 weeks with the understanding that demand beyond Week 2 is tentative and subject to change depending on auto sales during the preceding weeks. Table 1 shows the projected demand for the next 12 weeks. FDC can produce the parts on five die casting machines, each of which is capable of producing a subset of the parts as indicated in Table 2. For example, Part 1 can be produced only on Machines 1 and 2.

Seed localization uses a radioactive source to identify nonpalpable breast lesions for excision; it is an emerging alternative to wire localization (WL). Previous single health system studies report decreased rates of re-excision and improved patient convenience with this technique. This study is the first to implement this procedure in a public health care delivery system composed of a primarily minority and low-income population. A multidisciplinary team was formed to create a protocol for breast seed localization (BSL) and monitor the results. After 50 seed localizations were successfully completed, a retrospective matched-pair analysis with patients who had undergone WL during the same period was performed. Overall experience with the BSL protocol is reviewed, along with the occurrence of a seed loss. Processes necessary to reactivate the BSL protocol and prevent future losses are delineated. BSL is associated with decreased rates of re-excision and can be successfully implemented in a public health care system. BSL is an attractive alternative to WL in a high-volume, county-based population. It allows increased efficiency in the operating room and has a low rate of complications. Cautionary measures must be taken to ensure proper seed chain of custody to prevent seed loss.