148 research outputs found
Development of a simple, self-contained flight test data acquisition system
The flight test system described combines state-of-the-art microprocessor technology and high accuracy instrumentation with parameter identification technology which minimize data and flight time requirements. The system was designed to avoid permanent modifications of the test airplane and allow quick installation. It is capable of longitudinal and lateral-directional stability and control derivative estimation. Details of this system, calibration and flight test procedures, and the results of the Cessna 172 flight test program are presented. The system proved easy to install, simple to operate, and capable of accurate estimation of stability and control parameters in the Cessna 172 flight tests
Mushroom marketing: a case study in marketing at Mellow Mushroom Pizza Bakers downtown Chattanooga
This paper and the research within was written to address the specific issue of understanding the college student market and its attitudes towards Mellow Mushroom of Chattanooga. The end use of this paper is to develop marketing communications for Mellow Mushroom that are factually based and best reach the college student market in Chattanooga. Four objectives were defined as critical: (1) to measure UTC student attitudes towards Mellow Mushroom, (2) to compare Mellow Mushroom with local competition, (3) identify ways to attract students, (4) describe the college market. These objectives were used to develop a 54-question survey that was administered to 250 University of Tennessee at Chattanooga students the summer of 2003. The survey data gathered was analyzed and compared to known population data and evaluated in respect to the objectives. The data shows that only 51.2% of UTC students have eaten at Mellow Mushroom and the majority of those students only visit for special occasions. The conclusions and recommendations synthesize the information gathered from the data analysis and pose three possible directions that Mellow Mushroom could go with future marketing communications targeted at the college market. Each recommendation takes into account the project objectives, and the three marketing communications objectives of enhancing attitudes, influencing behavior, and 2 facilitating purchase. The key to these recommendations is their foundation in the understanding of the target market gained from this project
The Anthropometry of Forest Machine Operators in the Southern USA
Anthropometric dimensions critical to the design of operator workspaces and cab access in grapple skidders were collected from a sample of Southern United States loggers. The data were then compared to existing SAE and ILO anthropometric recommendations and data. Results indicated that southern grapple skidder operators are generally taller in stature, sitting height and seated eye height than the worldwide population measured to determine the SAE and ILO guides. Southern operators are also heavier than subjects measured for the SAE recommendations
Plow Power Requirements for Forestry Site Preparation
In this field study, data were collected to determine power requirements required by a trailing site preparation plow and the magnitudes of dynamic forces experienced by a plow during normal operation and during impact with stumps or other obstructions. Drawbar pull data were collected from five different tillage treatments on a recently harvested loblolly pine (Pinus taeda) site in central Alabama. The five treatments were: 1) a coulter, ripping shank, and four bedding disks; 2) a coulter, ripping shank, and two bedding disks; 3) a coulter and ripping shank; 4) a coulter alone; and 5) a ripping shank alone. A 330 kN [75 000 lb] capacity tension load cell was used to measure the drawbar load, a GPS receiver recorded tractor speed, four direct current displacement transducers (DCDT's) monitored the depth of the disks, and two optical tachometers measured the speed of the tractor's front and rear drive shafts. Each treatment produced significantly different drawbar loads (to alpha levels less than 0.001). The resulting mean loads were 46.0 kN [10 300 lb], 33.5 kN [7530 lb], 31.5 kN [7080 lb], 15.8 kN [3560 lb], and 43.4 kN [9760 lb] for treatments one through five, respectively. Maximum recorded drawbar load during a collision with a stump was 338.9 kN [76 188 lb]
Nonlethally assessing elasmobranch ontogenetic shifts in energetics
Body condition is an important proxy for the overall health and energetic status of fishes. The classically used Fulton's condition factor requires length and mass measurements, but mass can be difficult to obtain in large species. Girth measurements can replace mass for wild pelagic sharks. However, girth-calculated condition has not been validated against Fulton's condition factor intraspecifically, across ontogeny or reproduction, or in a controlled setting. We used the epaulette shark (Hemiscyllium ocellatum), because they are amenable to captive reproduction, to track fine-scale body condition changes across life stages, oviparous reproduction and between condition indices. We measured four girths, total length and mass of 16 captive epaulette sharks across 1 year and tracked female reproduction daily. We also collected length and mass data from an additional 72 wild-caught sharks and 155 sharks from five previous studies and two public aquaria to examine the relationship between length and mass for this species. Even though data were derived from a variety of sources, a predictable length–mass relationship (R2 = 0.990) was achievable, indicating that combining data from a variety of sources could help overcome knowledge gaps regarding basic life history characteristics. We also found that condition factor decreased during early life stages, then increased again into adulthood, with predictable changes across the female reproductive cycle. Finally, we determined that both Fulton's and girth condition analyses were comparable. Outcomes from this study uniquely provide body condition changes across the complete life history, including fine-scale female reproductive stages, and validate the use of girths as a nonlethal whole-organism energetic assessment for fishes
The upper thermal limit of epaulette sharks (Hemiscyllium ocellatum) is conserved across three life history stages, sex and body size
Owing to climate change, most notably the increasing frequency of marine heatwaves and long-term ocean warming, better elucidating the upper thermal limits of marine fishes is important for predicting the future of species and populations. The critical thermal maximum (CTmax), or the highest temperature a species can tolerate, is a physiological metric that is used to establish upper thermal limits. Among marine organisms, this metric is commonly assessed in bony fishes but less so in other taxonomic groups, such as elasmobranchs (subclass of sharks, rays and skates), where only thermal acclimation effects on CTmax have been assessed. Herein, we tested whether three life history stages, sex and body size affected CTmax in a tropical elasmobranch, the epaulette shark (Hemiscyllium ocellatum), collected from the reef flats surrounding Heron Island, Australia. Overall, we found no difference in CTmax between life history stages, sexes or across a range of body sizes. Findings from this research suggest that the energetically costly processes (i.e. growth, maturation and reproduction) associated with the life history stages occupying these tropical reef flats do not change overall acute thermal tolerance. However, it is important to note that neither embryos developing in ovo, neonates, nor females actively encapsulating egg cases were observed in or collected from the reef flats. Overall, our findings provide the first evidence in an elasmobranch that upper thermal tolerance is not impacted by life history stage or size. This information will help to improve our understanding of how anthropogenic climate change may (or may not) disproportionally affect particular life stages and, as such, where additional conservation and management actions may be required
Future thermal regimes for epaulette sharks (Hemiscyllium ocellatum): growth and metabolic performance cease to be optimal
Climate change is affecting thermal regimes globally, and organisms relying on their environment to regulate biological processes face unknown consequences. In ectotherms, temperature affects development rates, body condition, and performance. Embryonic stages may be the most vulnerable life history stages, especially for oviparous species already living at the warm edge of their distribution, as embryos cannot relocate during this developmental window. We reared 27 epaulette shark (Hemiscyllium ocellatum) embryos under average summer conditions (27 °C) or temperatures predicted for the middle and end of the twenty-first century with climate change (i.e., 29 and 31 °C) and tracked growth, development, and metabolic costs both in ovo and upon hatch. Rearing sharks at 31 °C impacted embryonic growth, yolk consumption, and metabolic rates. Upon hatch, 31 °C-reared sharks weighed significantly less than their 27 °C-reared counterparts and exhibited reduced metabolic performance. Many important growth and development traits in this species may peak after 27 °C and start to become negatively impacted nearing 31 °C. We hypothesize that 31 °C approximates the pejus temperature (i.e., temperatures at which performance of a trait begin to decline) for this species, which is alarming, given that this temperature range is well within ocean warming scenarios predicted for this species’ distribution over the next century
Validation of a portable, waterproof blood pH analyser for elasmobranchs
Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH values measured using a portable, waterproof pH meter (Hanna Instruments HI 99161) with blood pH values measured by an i- STAT system (CG4+ cartridges), which was previously validated for teleost and elasmobranch fishes, to gauge the accuracy of the pH meter in determining whole blood pH for the Cuban dogfish (Squalus cubensis) and lemon shark (Negaprion brevirostris). There was a significant linear relationship between values derived via the pH meter and the i- STAT for both species across a wide range of pH values and temperatures (Cuban dogfish: 6.8-7.1 pH 24-30 degrees C; lemon sharks: 7.0-7.45 pH 25-31 degrees C). The relative error in the pH meter's measurements was similar to +/- 2.7%. Using this device with appropriate correction factors and consideration of calibration temperatures can result in both a rapid and accurate assessment of whole blood pH, at least for the two elasmobranch species examined here. Additional species should be examined in the future across a wide range of temperatures to determine whether correction factors are universal
Investigating the roles of phonological and semantic memory in sentence recall
The mechanisms underlying short-term sentence recall have been the subject of recent investigations. While both semantic and phonological information have been found to play a role in sentence recall, this has been established using different paradigms in previous research. As a result, it is not clear whether the contributions of semantic and phonological information are equivalent subject only to specific experimental conditions. The present study used a common paradigm with equally plausible lures to systematically compare the roles of semantic and phonological information in short-term sentence recall. The lure intrusion paradigm was used with three different lures that were all equally plausible in the context of the sentence: semantic, onset, and rhyme. Further, no contextual cues were provided in the sentence to bias the participant. The findings indicate that there were significantly more semantic and onset intrusions compared to rhyme intrusions. This is interpreted in light of models incorporating lexical information during sentence production
How experimental biology and ecology can support evidence-based decision-making in conservation: avoiding pitfalls and enabling application
Policy development and management decisions should be based upon the best available evidence. In recent years, approaches to evidence synthesis, originating in the medical realm (such as systematic reviews), have been applied to conservation to promote evidence-based conservation and environmental management. Systematic reviews involve a critical appraisal of evidence, but studies that lack the necessary rigour (e.g. experimental, technical and analytical aspects) to justify their conclusions are typically excluded from systematic reviews or down-weighted in terms of their influence. One of the strengths of conservation physiology is the reliance on experimental approaches that help to more clearly establish cause-and-effect relationships. Indeed, experimental biology and ecology have much to offer in terms of building the evidence base that is needed to inform policy and management options related to pressing issues such as enacting endangered species recovery plans or evaluating the effectiveness of conservation interventions. Here, we identify a number of pitfalls that can prevent experimental findings from being relevant to conservation or would lead to their exclusion or down-weighting during critical appraisal in a systematic review. We conclude that conservation physiology is well positioned to support evidence-based conservation, provided that experimental designs are robust and that conservation physiologists understand the nuances associated with informing decision-making processes so that they can be more relevant
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