Using the ‘Engagement’ Model of Problem Solving to Assist Students in Capstone Learning

The engagement model for problem solving was developed as a response to soft systems methodology being difficult to implement in certain circumstances. In the years since the original paper was published, the model has developed into an iterative problem solving approach for the assessment, creation and implementation of new ideas in difficult problem situations. This case study paper exemplifies the kind of work undertaken through the use of the model and provides a practical scenario for how one might apply it. The case study takes place in a higher education environment and relates to the development of a capstone course for management majors. The paper concludes with suggestions for future research.     

Sensitivity to antitubulin chemotherapeutics is regulated by MCL1 and FBW7

Microtubules have pivotal roles in fundamental cellular processes and are targets of antitubulin chemotherapeutics. Microtubule-targeted agents such as Taxol and vincristine are prescribed widely for various malignancies, including ovarian and breast adenocarcinomas, non-small-cell lung cancer, leukaemias and lymphomas. These agents arrest cells in mitosis and subsequently induce cell death through poorly defined mechanisms. The strategies that resistant tumour cells use to evade death induced by antitubulin agents are also unclear. Here we show that the pro-survival protein MCL1 (ref. 3) is a crucial regulator of apoptosis triggered by antitubulin chemotherapeutics. During mitotic arrest, MCL1 protein levels decline markedly, through a post-translational mechanism, potentiating cell death. Phosphorylation of MCL1 directs its interaction with the tumour-suppressor protein FBW7, which is the substrate-binding component of a ubiquitin ligase complex. The polyubiquitylation of MCL1 then targets it for proteasomal degradation. The degradation of MCL1 was blocked in patient-derived tumour cells that lacked FBW7 or had loss-of-function mutations in FBW7, conferring resistance to antitubulin agents and promoting chemotherapeutic-induced polyploidy. Additionally, primary tumour samples were enriched for FBW7 inactivation and elevated MCL1 levels, underscoring the prominent roles of these proteins in oncogenesis. Our findings suggest that profiling the FBW7 and MCL1 status of tumours, in terms of protein levels, messenger RNA levels and genetic status, could be useful to predict the response of patients to antitubulin chemotherapeutics.     

Dispersal and extraterritorial movements of swift foxes ( Vulpes velox ) in northwestern Texas

Dispersal plays an important role in the population dynamics of many carnivores, yet little information exists about the dispersal and movement patterns of swift foxes ( Vulpes velox ). We radio-collared and monitored 68 swift foxes for dispersal at 2 study sites in northwestern Texas from January 2002 to April 2004. Dispersal distance for juveniles (13.1 ± 0.3 km, s ), adults (10 ± 4.7 km) and transients (25.4 ± 9.1 km) did not differ by age class ( F = 1.49, df = 2, P = 0.24) or sex ( F = 0.23, df = 1, P = 0.63) but differed by study site ( F = 4.72, df = 1, P = 0.04). Mean dispersal distance from private ranches (PR) was greater than from National Grasslands (NG). Peak dispersal occurred during October– November (13 individuals) and January–February (7 individuals). Dispersal direction was influenced by land-use practices (i.e., toward rangelands and away from anthropogenic features). Direction of dispersal among foxes that occupied the NG was uniform ( n = 16, P = 0.08), whereas foxes from PR dispersed in a northwesterly direction ( n = 18, P ≤ 0.001) away from a town and croplands. Three resident adult foxes made extraterritorial movements. Distances of these movements ranged from 0.2 km to 11.4 km. Distance of extraterritorial movements did not differ by sex ( F = 0.05, P = 0.83), nor by duration of movement ( F = 1.11, P = 0.32). Knowledge of movement distances and patterns is important for conservation and protection of swift foxes and their habitats.     

Predatory bird populations in the east Mojave Desert, California

We surveyed 7 species of predatory birds weekly during a 12-month period (December 1992 through November 1993) in the east Mojave Desert, California. The Common Raven ( Corvus corax ) was the most frequently observed species with an average of 6.9 sightings per 100 km. Turkey Vultures ( Cathartes aura ), Red-tailed Hawks ( Buteo jamaicensis ), Loggerhead Shrikes ( Lanius ludovicianus ), American Kestrels ( Falco sparverius ), Golden Eagles ( Aquila chrysaetos ), and Prairie Falcons ( Falco mexicanus ) were seen in decreasing order of frequency of observation through the study period. Ravens, Red-tailed Hawks, Loggerhead Shrikes, American Kestrels, and Prairie Falcons were seen throughout the year. Turkey Vultures were not present during winter months, while Golden Eagles were seen only during November and December. Turkey Vultures, Red-tailed Hawks, and ravens were most numerous on agricultural lands, while Loggerhead Shrikes were most common at urban areas. Raven numbers increased with increasing number of linear rights-of-way parallel to the survey route. Perching was the most common behavior type, although Turkey Vultures and ravens were often observed soaring, flying, or standing on the ground near highways. Transmission powerline towers and telephone poles were used as perch sites disproportionately to availability.     

Distribution and first reports of Branchiobdellida (Annelida: Clitellata) on crayfish in the prairie provinces of Canada

Orconectes virilis (northern crayfish) were collected from 67 sites in Alberta, Saskatchewan, Manitoba, and far-western Ontario, Canada, and yielded 2 species of branchiobdellidans, Cambarincola vitreus and Cambarincola chirocephalus. This is the first report of branchiobdellidans in the Prairie Provinces. Cambarincola vitreus was distributed across the study area, but C. chirocephalus appeared to be restricted to southeastern Saskatchewan, southern Manitoba, and the site in western Ontario. Neither branchiobdellidan species was observed on crayfish in the Beaver River or the South Saskatchewan River and associated tributaries upstream (west) of Saskatoon, Saskatchewan, despite multiple sampling at these locations.     

Evolutionary information for specifying a protein fold

Classical studies show that for many proteins, the information required for specifying the tertiary structure is contained in the amino acid sequence. Here, we attempt to define the sequence rules for specifying a protein fold by computationally creating artificial protein sequences using only statistical information encoded in a multiple sequence alignment and no tertiary structure information. Experimental testing of libraries of artificial WW domain sequences shows that a simple statistical energy function capturing coevolution between amino acid residues is necessary and sufficient to specify sequences that fold into native structures. The artificial proteins show thermodynamic stabilities similar to natural WW domains, and structure determination of one artificial protein shows excellent agreement with the WW fold at atomic resolution. The relative simplicity of the information used for creating sequences suggests a marked reduction to the potential complexity of the protein-folding problem.     

Behavioural ecology: bees associate warmth with floral colour

Floral colour signals are used by pollinators as predictors of nutritional rewards, such as nectar. But as insect pollinators often need to invest energy to maintain their body temperature above the ambient temperature, floral heat might also be perceived as a reward. Here we show that bumblebees (Bombus terrestris) prefer to visit warmer flowers and that they can learn to use colour to predict floral temperature before landing. In what could be a widespread floral adaptation, plants may modulate their temperature to encourage pollinators to visit.     

Do female hyaenas choose mates based on tenure?

In their investigation into whether female mate-choice drives male dispersal, H?ner et al. argue that female spotted hyaenas (Crocuta crocuta) prefer mates whose tenure in the social group is less than the females' age, to avoid paternal incest, and suggest that male dispersal reflects this preference. However, we are not persuaded that females choose mates on the basis of tenure because H?ner et al. overlook the alternative hypothesis that dispersal status itself is important in female mate-choice, such that females prefer immigrants over natal males. Like mate-choice based on tenure, choice based on dispersal status reduces the risk of incest.