Boundary as Borderland: Mexico City’s Central Plaza and the Politics of Presence

In the postcolonial era, the land surrounding national borders—the borderland—has inherited a specific identity and relationship with those who navigate it. While national borderlands are oft discussed amid conversations on globalization, land disputes, and war, the Spanish colonization of the Americas in the fifteenth and sixteenth centuries saw the new establishment of borderlands from within in the form of segregative boundaries that purported to separate Indigenous and European peoples. This thesis concerns the manifestation of the borderland as not only an external entity, but an internal one as well. Using Mexico City, the center of the Spanish colonial empire, as the primary case study, this thesis demonstrates how internal segregative boundaries ontologically function as a borderland—not necessarily a demarcation of a physical territory, but a social boundary, a manifestation of power that engenders the social and physical marginalization of nonhegemonic communities

Synergistic reinforcement of a reversible Diels-Alder type network with nanocellulose

Covalent adaptable networks are attractive intermediates between thermosets and thermoplastics. To achieve an optimal combination of dimensional stability at the temperature of use and macroscopic flow at elevated temperatures, materials that combine two reversible networks are highly sought after. We demonstrate that such a material can be created through the addition of cellulose microfibrils to a polymer matrix that can undergo thermoreversible Diels-Alder reactions. The cellulose microfibrils and crosslinked polymer form two independent reversible networks that display clear synergistic effects on the thermomechanical properties of the nanocomposite. Above the glass transition temperature of the polymer matrix the two networks work in tandem to reduce tensile creep by a factor of 40 at 80 degrees C, while increasing the storage modulus by a factor of 60 at the same temperature. The adaptability of the Diels-Alder network is not compromised by the addition of cellulose microfibrils, as shown by kinetic studies and repeated reprocessing. Further, the cellulose network significantly improves the dimensional stability at elevated temperatures where the Diels-Alder network dissociates

Development of a flaming machine for the disinfection of poultry grow-out facilities

Chemical treatments are commonly adopted for poultry house sanitation. In fact, ordinary floor disinfection is needed to deplete the pathogenic population (i.e. various species of bacteria and fungi) and reduce the risk of meat contamination. The increasing focus on the health of consumers and operators, as well as on food quality, has led farmers to consider alternative environmentally friendly methods. Research was carried out to set up a new machine for floor disinfection of poultry houses by open flame. The trials were run in controlled conditions in the laboratory of the University of Pisa, Italy, and on a private farm. The first experiment consisted of a series of test bench trials carried out to evaluate the efficacy and the adjustment of liquefied petroleum gas (LPG)-fed open flame burners on pre-inoculated steel plates. In the second experiment, the operative parameters of a custom-built 1.5 m wide mounted flaming machine were determined and the biological effects of the treatment were compared to ordinary chemical treatments. The results obtained were very promising. Test bench trials showed a 4-log reduction in E. coli, and microbial determinations carried out on-farm did not show any difference between thermal and chemical treatment. In addition, the cost estimation showed that thermal disinfection is approximately 4-fold cheaper than chemical sanitation methods. The effective working capacity of the machine was approximately 1700 m2 h–1, and the LPG consumption was approximately 16 kg per 1000 m2. Flame disinfection of poultry grow-out facilities could represent a valid alternative to chemical disinfection

Single Gene Deletions of Orexin, Leptin, Neuropeptide Y, and Ghrelin Do Not Appreciably Alter Food Anticipatory Activity in Mice

Timing activity to match resource availability is a widely conserved ability in nature. Scheduled feeding of a limited amount of food induces increased activity prior to feeding time in animals as diverse as fish and rodents. Typically, food anticipatory activity (FAA) involves temporally restricting unlimited food access (RF) to several hours in the middle of the light cycle, which is a time of day when rodents are not normally active. We compared this model to calorie restriction (CR), giving the mice 60% of their normal daily calorie intake at the same time each day. Measurement of body temperature and home cage behaviors suggests that the RF and CR models are very similar but CR has the advantage of a clearly defined food intake and more stable mean body temperature. Using the CR model, we then attempted to verify the published result that orexin deletion diminishes food anticipatory activity (FAA) but observed little to no diminution in the response to CR and, surprisingly, that orexin KO mice are refractory to body weight loss on a CR diet. Next we tested the orexigenic neuropeptide Y (NPY) and ghrelin and the anorexigenic hormone, leptin, using mouse mutants. NPY deletion did not alter the behavior or physiological response to CR. Leptin deletion impaired FAA in terms of some activity measures, such as walking and rearing, but did not substantially diminish hanging behavior preceding feeding time, suggesting that leptin knockout mice do anticipate daily meal time but do not manifest the full spectrum of activities that typify FAA. Ghrelin knockout mice do not have impaired FAA on a CR diet. Collectively, these results suggest that the individual hormones and neuropepetides tested do not regulate FAA by acting individually but this does not rule out the possibility of their concerted action in mediating FAA

Systems approaches to modelling pathways and networks.

Peer reviewedPreprin