The Development of Bridge Inspection Strategies Based on a Statistical Analysis of Deterioration in Underwater Structures.

A comprehensive statistical analysis was performed on the condition data generated by a statewide underwater inspection of bridges in Louisiana. The research defined pertinent underwater structural decay characteristics and established a method for establishing a bridge\u27s propensity for underwater deterioration based upon those relevant factors. The inspection results were reviewed to ascertain the impact of human-bias on the consistency in the bridge condition ratings. Using a set of importance factors obtained through a questionnaire submitted to a group of inspectors, the fuzzy set theory was employed to assist in the removal of data incongruities. A combination of pure fuzzy set theory and classical binary weighting was found to produce optimal results. Bridge age, material-type, and location were found to be significant in defining the rate of deterioration in Louisiana bridges. Linear least-squares, piece-wise linear least-squares, and polynomial regression curves were matched to the overall underwater condition ratings, with the piece-wise linear least-square curves providing the optimal fit for concrete and steel bent bridges and linear least-squares best describing the regression of timber bent bridges. For concrete and steel bent bridges, significant changes in deterioration rates were found at ages of 20 and 40 years. Comparisons of regression curves for neighboring states indicated reasonable consistency in results for different inspection programs if similar inspection methodologies are employed. The correlation between above-water and subsurface inspection ratings was found to be poor for concrete and steel bent bridges, but acceptable for timber bent bridges within a given age group. Additionally, a poor correlation was found between water quality data and underwater bridge deterioration rates. A methodology for determining the frequency and detail of future underwater inspection projects was developed based upon the deterioration trends and available bridge decay-defining characteristics discovered in this research

Matrix metalloproteinases in the equine systemic inflammatory response: implications for equine laminitis

Laminitis is a crippling and often life-threatening disease of the equine foot. Soft tissue damage characteristic of this disease has been associated with increased MMP activity. Therefore, it seems likely that MMPIs could be potential therapeutic agents for laminitis. Further characterization of equine MMPs and evaluation of the effectiveness of MMPIs in the horse are needed. Equine MMP-9 was harvested from neutrophils, purified by affinity chromatography, and evaluated using western blotting and gelatin zymography. The Biotrak MMP-9 Activity Assay was evaluated for use with equine samples using equine neutrophil MMP-9 as a standard, and was determined to have insufficient sensitivity for equine MMP-9. Therefore, zymography was used for evaluating MMP activity in all studies. The abilities of doxycycline, oxytetracycline, and flunixin meglumine to inhibit LPS-induced equine MMP-2 and MMP-9 activities in vitro were investigated using a digital laminar explant model. The structural integrity of the explants was tested using an Instron biomechanical testing device, and MMP activity in the explants medium was evaluated using zymography. Doxycycline, oxytetracycline, and flunixin meglumine all successfully inhibited equine MMP-9 to varying degrees. However, only doxycycline and oxytetracycline increased the structural integrity of the explants. Explant structural integrity was inversely correlated with MMP-2 concentrations in the medium. Based on the in vitro results, a non-terminal in vivo model for investigating MMPIs in the horse was validated. The administration of IV endotoxin to normal adult horses resulted in significant increases in MMP-2 and MMP-9 activities, as assessed by zymography. This in vivo model of MMP induction was used to determine the effects of doxycycline, oxytetracycline, flunixin meglumine, and pentoxifylline on equine MMP inhibition. Pentoxifylline and oxytetracycline appeared to be potent MMP-9 and modest MMP-2 inhibitors in the horse. Flunixin meglumine and doxycycline were potent inhibitors of equine MMP-2, but only weak inhibitors of equine MMP-9. These findings warrant the evaluation of pentoxifylline and oxytetracycline as MMPIs in the prevention/treatment of equine laminitis

Comparison between several operant procedures with severely retarded children

This study was designed to examine: (a) The effects of social and token reinforcement in increasing instruction-following behaviour in retarded children, where the class was addressed as a whole; (b) The effects of time-out and verbal reprimand as methods of reducing disruptive behaviour; (c) The effects of the administration of social reinforcement (verbal praise), in increasing behaviour defined as helping other children. Results show that token reinforcement is significantly more effective than social reinforcement in generating and maintaining instruction-following behaviour in a sample of severely retarded children. This supports the results of a growing body of literature relating to both the theoretical and applied aspects of reinforcement procedures. The time-out procedure was found to reduce disruptive responses at a more rapid rate than that of verbal reprimand and the effects were more lasting over time. This result was achieved using a 60 second isolation period. Verbal reprimand was found to reduce disruptive responses to slightly below the non punished level. Suggestions are made as to further developments in both procedures. The administration of verbal praise, delivered contingent upon one child helping another, led to an increase in this class of response in three children. No general conclusions can be made as to the effectiveness of this type of reinforcement in increasing helping behaviour in a group situation. The results obtained in this study further suggest that the approach taken can be successfully applied to the problem of altering the behaviour of individuals treated as a group, in a group setting. This applies to both the reinforcement and punishment conditions. The results further indicate that the systematic application of operant learning principles will both increase adaptive and decrease maladaptive behaviour in retarded children

Performance of installed cooking exhaust devices

The performance metrics of airflow, sound, and combustion product capture efficiency (CE) were measured for a convenience sample of fifteen cooking exhaust devices, as installed in residences. Results were analyzed to quantify the impact of various device- and installation-dependent parameters on CE. Measured maximum airflows were 70% or lower than values noted on product literature for 10 of the devices. Above-the-cooktop devices with flat bottom surfaces (no capture hood) – including exhaust fan/microwave combination appliances – were found to have much lower CE at similar flow rates, compared to devices with capture hoods. For almost all exhaust devices and especially for rear-mounted downdraft exhaust and microwaves, CE was substantially higher for back compared with front burner use. Flow rate, and the extent to which the exhaust device extends over the burners that are in use, also had a large effect on CE. A flow rate of 95 liters per second (200 cubic feet per minute) was necessary, but not sufficient, to attain capture efficiency in excess of 75% for the front burners. A-weighted sound levels in kitchens exceeded 57 dB when operating at the highest fan setting for all 14 devices evaluated for sound performance

Invasive species control: incorporating demographic data and seed dispersal into a management model for Rhododendron ponticum

Rhododendron ponticum is a serious invasive alien plant in the British Isles and is of significant conservation and economic concern. Here, we integrate information on both the life-history and spatial dynamics of this species within an individual-based, spatially-explicit model and investigate the effectiveness of different control strategies. Importantly, we simulate seed movement and dispersal using a mechanistic seed dispersal model. We investigate the effectiveness of initiating control at the edge versus the core of the infestation, with and without returning each year to remove seedlings. We compare these results to an age-dependent strategy whereby the oldest plants are removed each year. Age-dependent control, in which the oldest plants were removed first, was the most effective strategy investigated, both in terms of the probability of successful eradication and the number of years taken to control. We demonstrate that this is because the older (and taller) plants towards the core produce more seeds that, on average, travel further. Indeed, our results suggest that the expansion of the invading front is actually driven as much by seeds that disperse long distances from these larger plants as by the seed rain from recently matured plants located much closer to the front. Finally, we investigate the potential use of ‘quarantine lines’ - corridors of unsuitable habitat that are sufficiently wide to contain an infestation, preventing spread to vulnerable areas. This study has provided generic insights into best practice for management based on the current understanding of the biology and ecology of this pernicious, invasive plant

Pre-compositional mathematical planning in mass settings by Nicholas Ludforda and Robert Fayrfax

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