The amniote egg was a key innovation in vertebrate evolution because it supports an independent existence in terrestrial environments. The egg is provisioned with yolk, and development depends on the yolk sac for the mobilization of nutrients. We have examined the yolk sac of the corn snake Pantherophis guttatus by the dissection of living eggs. In contrast to the familiar fluid-filled sac of birds, the corn snake yolk sac invades the yolk mass to become a solid tissue. There is extensive proliferation of yolk-filled endodermal cells, which associate with a meshwork of blood vessels. These novel attributes of the yolk sac of corn snakes compared with birds suggest new pathways for the evolution of the amniote egg.

The work in this thesis was based on analyzing water samples collected from three exploratory boreholes drilled during Project Hotspot. The water samples were analyzed for their chemical properties. The chemical properties of the water samples were used as a basis for further analysis.Geophysical logs, mainly temperature logs, were also analyzed for this project. Temperature logs measure temperature in relation to depth within a borehole.All the analyses were made in order to estimate the geothermal potential of the project areas. The exploratory boreholes were all drilled in different areas and each had unique characteristics. The Mountain Home borehole provided the most promising evidence for future geothermal potential. Geothermal energy is a form of renewable energy and potential production areas are difficult and expensive to locate.

The Snake River Plain is located in the southern part of the state of Idaho. The eastern plain, on which this study focuses, is a trail of volcanics from the Yellowstone hotspot. Three exploratory geothermal wells were drilled on the Snake River Plain. This project analyzes basaltic core from the first well at Kimama, north of Burley, Idaho. The objectives of this project are to establish zones of geothermal alteration and analyze the potential for geothermal power production using sub-aquifer resources on the axial volcanic zone of the Snake River Plain. Thirty samples from 1,912 m of core were sampled and analyzed for clay content and composition using X-ray diffraction. Observations from core samples and geophysical logs are also used to establish alteration zones. Mineralogical data, geophysical log data and physical characteristics of the core suggest that the base of the Snake River Plain aquifer at the axial zone is located 960m below the surface, much deeper than previously suspected. Swelling smectite clay clogs pore spaces and reduces porosity and permeability to create a natural base to the aquifer. Increased temperatures favor the formation of smectite clay and other secondary minerals to the bottom of the hole. Below 960 m the core shows signs of alteration including color change, formation of clay, and filling of other secondary minerals in vesicles and fractured zones of the core. The smectite clay observed is Fe-rich clay that is authigenic in some places. Geothermal power generation may be feasible using a low temperature hot water geothermal system if thermal fluids can be attained near the bottom of the Kimama well. (113 pages)

The role of bison in the prehistoric subsistence in southern Idaho is not fully understood. Bison remains from Baker Cave, a late Holocene archaeological site dating to cal A.D. 1042-1265, however, provide evidence of pre-contact subsistence strategies in the region. This thesis focuses on the paleoecology of bison and their role in prehistoric subsistence on the Snake River Plain (SRP). The ecological study of bison focuses on the hypothesized trans-Holocene diminution in bison body size in southern Idaho, while a second study focuses on how these animals figured into prehistoric responses to seasonal fat scarcity. Although bison diminution and its ecological determinants are well understood on the Great Plains, the history of diminution west of the Rocky Mountains is less clear. Bison morphometrics from Baker Cave present the opportunity to assess bison diminution on the Snake River Plain. Bison morphometrics from Baker Cave are indistinguishable not only from other late Holocene bison on the Snake River Plain but iv also from late Holocene bison from the Great Plains. Further, the Baker Cave bison are smaller than early Holocene bison from the Great Plains and Snake River Plain. These results suggest morphological similarity between Snake River Plain bison and Great Plains bison through the Holocene, pointing to similar bottom up ecological constraints on body size. Although bison are common components of SRP archaeofaunas, their role in prehistoric subsistence is poorly understood. To shed light on this problem, I hypothesize that the Baker Cave bison assemblage resulted from hunters seeking skeletal fat. I test predictions drawn from this hypothesis with assemblage-level patterns in element representation, impact scar distribution, and fragmentation. These assemblage-level patterns track the skeletal fat utility of elements. These patterns, combined with winter procurement evidenced by fetal remains, support the hypothesis that fat-seeking behavior was a response to winter fat scarcity. A comparison with smaller bison assemblages from southern Idaho suggests that this fat-seeking behavior might have persisted as far back as the middle Holocene, although this requires confirmation from future studies.

Mechanisms of how red-sided garter snakes (Thamnophis sirtalis parietalis) travel up to 18 km from summer feeding sites to hibernation dens are not understood. In this study, monthly and seasonal trailing behavior were investigated to determine whether red-sided garter snakes prefer to follow trails of snakes from the same den (den-mates) versus trails made by other conspecifics (non-den-mates). Snakes from five different hibernacula in Manitoba, Canada, were involved in the study. Eighteen were adults and 15 were subadults. Subadult red-sided garter snakes do not return to hibernacula until their second year of life, so their trailing behavior was of interest in learning how they might first find hibernation sites.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18104号 / 理博第3982号 / 新制||理||1574(附属図書館) / 30962 / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 森 哲, 教授 沼田 英治, 教授 疋田 努 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

The Fremont, a Formative culture located in the Eastern Great Basin and Colorado Plateau, have been primarily studied from an ecological perspective. This research addresses issues that are not ecological, the organization of production and exchange of ceramic vessels. Following criteria suggested by Brown et al. (1990), I argue that the following need to be addressed prior to a useful discussion of intergroup trade: the source of the raw materials of the exchanged objects, the associated pattern of distribution, the relative value of the objects, and their context of manufacture, use, and consumption. I specifically address three of these issues regarding the Snake Valley pottery series, asking what is the source of Snake Valley Black-on-gray pottery, what is the distribution of Snake Valley Gray, Snake Valley Black-on-gray, and Snake Valley Corrugated, and in what context was Snake Valley Black-on-gray manufactured? These questions are approached via two data sets -- a chemical assay and a distributional analysis. I argue that Snake Valley pottery was probably produced in a restricted area, the Parowan Valley, and that production was organized as community craft specialization, though I acknowledge that more research on this topic is ultimately required.

Reptiles exhibit neurogenesis throughout the brain during adulthood. However, very few studies have quantified telencephalon-wide neurogenesis in adulthood, and no studies have performed these investigations in snakes. Quantifying neurogenesis in the adult snake is essential to understanding class-wide adult neurogenesis and providing insight into the evolution of this trait. The thymidine analog 5-bromo-2’-deoxyuridine (BrdU) was used to quantify cell proliferation, migration, and survival in the ball python (Python regius). First, to determine the proper dose of BrdU for injection we subcutaneously injected 50mg/kg, 100mg/kg, and 250mg/kg into 15 adult male P. regius. We found the 250mg/kg dose marked significantly more cells than the 50mg/kg dose, but not the 100mg/kg dose. Then we subcutaneously injected 100mg/kg BrdU into 15 juvenile male P. regius at 3 different time points (2 days, 2 weeks, 2 months) prior to sacrifice to quantify proliferation, migration, and survival of cells in several telencephalic subregions. After sectioning and immunohistochemical staining, we found proliferation to be highest in the accessory olfactory bulb (AoB), retrobulbar regions (AD, AV), dorsal ventricular ridge (DVR), and dorsolateral amygdala/lateral amygdala (DLA/LA). Of the proliferating cells, the proportions of cells that migrated after 2 weeks were highest in the ventral lateral region (VL), anterior medial and lateral cortices (aMC, aLC), and anterior NS (aNS). After 2 months, the highest proportional survival was in the AoB, aLC, aMC, aNS, DVR, and ventral medial regions (VM). Regions involved in long-term functions like spatial memory may require less proliferation and longer survival, while regions involved in short-term functions undergo more proliferation with higher relative attrition.

Yes / A confocal microscope provides a sequence of images of the corneal layers and structures at different depths from which medical clinicians can extract clinical information on the state of health of the patient’s cornea. Hybrid model based on snake and particle swarm optimisation (S-PSO) is proposed in this paper to analyse the confocal endothelium images. The proposed system is able to pre-process (quality enhancement, noise reduction), detect the cells, measure the cell density and identify abnormalities in the analysed data sets. Three normal corneal data sets acquired using confocal microscope, and two abnormal endothelium images associated with diseases have been investigated in the proposed system. Promising results are achieved and the performance of this system are compared with the performance of two morphological based approaches. The developed system can be deployed as clinical tool to underpin the expertise of ophthalmologists in analysing confocal corneal images.

Emerging wildlife diseases represent a serious threat to conservation efforts. Impacts of emerging multi-host pathogens can vary greatly among species as well as geographically, and understanding which populations will be at greatest risk is essential for conserving biodiversity. Snake fungal disease (SFD), caused by the fungal pathogen Ophidiomyces ophidiicola, is responsible for lethal infections in snakes and has contributed to the decline of multiple North American snake populations. However, which species are most affected by this disease and how infections vary regionally remains unknown. Here we sampled 44 different species across 14 sites throughout the Southeastern and Mid-Atlantic United States. We found a strong effect of latitude on both pathogen prevalence and severity, with more severe infections at more northern latitudes. We also found high variability in pathogen prevalence and infection severity among species. There was a strong positive relationship between pathogen prevalence and disease severity, suggesting that SFD is not just highly prevalent in some populations but also highly virulent. More broadly, our results support that SFD likely has continued impacts on snake populations with some species experiencing greater disease than others attributed to spatial and host variation. / Master of Science / Conserving biodiversity is a significant challenge. Wildlife species are under multiple threats including habitat loss, changing climate, species introductions, pollution, and infectious diseases. Emerging wildlife diseases can pose a major problem for wildlife as they often go undetected until they cause substantial declines for the affected species, sometimes leading to population extirpations and extinction events. Snake fungal disease (SFD) is an emerging disease caused by the fungal pathogen Ophidiomyces ophidiicola, which has contributed to the decline of some North American snake populations. However, little is known about differences in infection, transmission, and host responses to SFD in a broader community context. To investigate the dynamics of this pathogen, we collected swab samples from 44 species from a total of 14 sites in New Jersey, Virginia, North Carolina, South Carolina, Georgia, Florida, and Louisiana. We sampled individual snakes to examine variation over a geographic gradient and among species. We found high variability among sites with more severe disease at northern sites. There was also high variability among species and some populations experienced both high pathogen prevalence and disease severity. Our results show that SFD is highly variable within snake communities and may still be causing population level effects.