Anthropogenic activities such as construction and agriculture directly affect its surrounding environments. Many studies have focused on how megafauna and flora are impacted by human activities, however, relatively little is known how new occupation of land affects smaller organisms such as insects and microbes. Additionally, other stressors such as predation can impact host physiology. The grasshopper species Melanopussanguinipes was chosen to be used in a study to measure how stress caused by artificial sound and predation can alter exoskeleton and gut microbiomes once exposed to these stressors.

Spider silk is a material that both has impressive mechanical properties and is also environmentally friendly. Though there are limitless potential engineering applications for such materials, industrial production of spider silk has proven to be challenging. Farming silk from spiders, as is done with silkworms, is not a viable option for large-scale production of spider silk due to the venomous and predatory nature of spiders. Here, an attempt is made to express synthetic spider silk minifibroins heterologously in Escherichia coli, to purify the recombinant spidroins from cell lysate, and to spin them into artificial fibers through a biomimetic process. Silk minifibroins were designed to be similar to Major Ampullate Spidroin 1 from Latrodectus hesperus. Synthetic fibers were examined by scanning electron and light microscopy, and their mechanical properties were tested by a tensometer. Properties of synthetic silk were compared to those of native dragline silk from the same species from which their design was inspired, revealing synthetic silk fibers with lower breaking stress and breaking strain.

No description available.

To mitigate climate change a proposed space-based geoengineering solutionis to screen off solar irradiance by placing a membrane in between the Earthand the Sun. The feasibility of such a project largely depends on minimizingthe mass of the shading screen and as an extension to the Sunshade projectthis thesis investigated how such a low-mass membrane could be designed.Because of the acting forces at location in space, minimizing the mass impliesthat the material ought to have a low reflection coefficient and surface densityand therefore the highly transparent material of artificial spider silk was chosenas the proposed material. The only possibility to block light is then byrefraction or diffraction and, since the presence of apertures might lower thesurface density, the structure of the suggested membrane is a grid patternof wires. Such a diffraction grating was investigated while applying twomethods. Method 1 optimized the dimensions of the structure to lower thetotal transmission on Earth when placed on the direct transmission axis ofthe membrane and method 2 tilted the membrane in order to place Earth ata diffraction minimum. This resulted in three suggested designs A, B, andC with surface densities varying from that of 0.00867 to 0.228 gm−2. Theresults were compared with two previous design proposals where the lowestareal density was 0.34g/m2, which is 3/2 to 40 times larger than the densitiesproposed in this paper. The reflectivities for A and B were 12.5 and 3.75 timeslarger than that of the smallest previously achieved reflectivity. The reflectivityof C could not be determined exactly but ought to have a reflectivity at leastas low as B at 3%, making it the most promising candidate for a membranedesign of the three.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24241号 / 農博第2520号 / 新制||農||1094(附属図書館) / 学位論文||R4||N5412(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 宮川 恒, 教授 三芳 秀人, 教授 森 直樹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Establishing baseline activity budgets for zoo-housed captive animals can be important in tracking behavior changes that may indicate medical or other concerns, as well as assessing overall welfare and the need for implementation of interventions such as increased amounts of enrichment. This study sought to calculate activity budgets for the current spider monkeys residing at the Central Florida Zoo, a father-daughter pair of Ateles geoffroyi. Having a baseline activity budget is also valuable because major changes in behavior may accompany the upcoming introduction of new individuals to this particular group of spider monkeys. BORIS behavior coding software was used to log behavior continuously over 58.3 hours of observation. The individuals in this zoo setting spent significantly more time stationary (resting or still and awake) and less time engaged in feeding behavior than wild spider monkeys. However, they spent as much or more of their time moving than Ateles species in natural settings. Temperature and exhibit renovation had minimal to no observed effects on activity budgets. Human presence usually has the effect of increasing activity and vigilance of animals while decreasing resting time, but on busier days at the zoo, one subject (a pet-reared male spider monkey) spent more time resting and less time moving than when there were fewer zoo visitors. No aggression was observed, but affiliative social behavior like allogrooming and embracing was observed infrequently. The study animals appeared to lack the bimodal pattern of activity (with activity peaking early and late in the day) common in wild spider monkeys, a finding that is consistent with activity budgets of other spider monkeys that are frequently exposed to humans. Time of day affected activity budgets to a small degree; the monkeys became more active later in the day and spent more time resting in the morning.

No description available.

No description available.

No description available.

No description available.