Determiniation of Anterior-Posterior Orientation of Glochidia by The Examination of Glochial Valves present within The Umbos of Juvenile Unionid Clams (Mollusca: Bivalvia)

Author Institution: The Ohio State University Museum of ZoologyThe terms anterior and posterior have been used differently by various authors working with the glochidia of the Unionidae. This report reviews the contradictory use of these terms in regard to glochidial orientation, and shows that the anterior and posterior margins of these minute parasitic larvae can be distinguished by demonstrating the morphological relationship between glochidial and juvenile shells. Glochidial valves, found upon examination of the umbos of juvenile clams, showed that the long side of the glochidium (measured from the middle of the dorsal margin to the base of the hook) corresponded to the anterior margin of the juvenile. The anterior margin of a glochidium may also be characterized as that margin closest to the single larval adductor muscle

Social Reorganization and Household Adaptation in the Aftermath of Collapse at Baking Pot, Belize

This dissertation focuses on the adaptations of ancient Maya households to the processes of social reorganization in the aftermath of collapse of Classic Maya rulership at Baking Pot, a small kingdom in the upper Belize River Valley of western Belize. With the depopulation of the central and southern Maya lowlands at the end of the Late Classic period, residents in Settlement Cluster C at Baking Pot persisted following the abandonment of the palace complex in the Terminal Classic period (A.D. 800-900). Results from this study indicate that noble and commoner households in Settlement Cluster C continued to live at Baking Pot, developing strategies of adaptation including expanding interregional mercantile exchange and hosting community feasts in the Terminal Classic and Early Postclassic periods. Breaking from the strict social hierarchies of the Classic period, households were increasingly participating in mercantile exchange in the Terminal Classic and Early Postclassic periods, with exotic luxury items becoming more evenly distributed throughout the community, particularly among commoner households. The even distributions of exotic items, coupled with low-level production of local resources, suggests that households were engaging in interregional networks of exchange, although this did not involve a complete reorganization of economic production. New relationships between noble and commoner households were forged, as noble households hosted large-scale community feasts during the Terminal Classic and Early Postclassic periods. Although households were not found to have been utilizing Pan-Mesoamerican symbols as a form of status differentiation, they did display local Maya iconography on ceramics and other media, displaying a sense of shared identity and cohesion. However, this and other forms of shared identity, such as burial practices, shifted in the transition to the Postclassic period. Overall, households at Baking Pot developed innovative strategies to adapt to the changing social landscape following the sociopolitical collapse of the Classic Maya polity, playing a prominent role in the in the processes of social reorganization in the Postclassic period

A study of the mussels (Mollusca: Bivalvia: Unionidae) of Symmes Creek and tributaries in Jackson, Gallia and Lawrence counties, Ohio

Freshwater mussels (family Unionidae) are among the most threatened of Ohio\u27s aquatic fauna. Interest in their biogeography has increased as their distribution and abundance has declined. This study was performed to assess the status of the mussels of Symmes Creek and it major tributaries in southern Ohio. Of the 24 species of mussels known to have inhabited this watershed, 16 were found alive in the system in 2004 and 2005 and two others were found as freshly dead shells. These species are thought to represent the extant mussel fauna in the system today. Of the remaining six species collected prior to the current study, three were found alive as single specimens and three were found as very old dead shells and so probably never represented viable populations in the system. During this study, four species were found that had never been reported from Symmes Creek before. These species are Simpsonaias ambigua (Ohio species of special concern), Quadrula pustulosa, Obliquaria reflexa (Ohio threatened species), and Ligumia recta (Ohio threatened species). The Ohio endangered mussel, Villosa lienosa, had been reported from the upper reaches of Symmes Creek previously and was collected alive during the current study, but in much fewer numbers than had previously been reported. The mussel community in the lower mainstem of Symmes Creek has remained healthy while the communities in the headwaters of Symmes Creek and its smaller tributaries have become severely reduced

Brief Note: Discovery of the Federally Endangered Freshwater Mussel, Epioblasma obliquata obliquata (Rafinesque, 1820) (Unionidae), in Ohio

Author Institution: Department of Life and Earth Sciences, Otterbein College ; Division of Natural Areas and Preserves, Ohio Department of Natural ResourcesDiscovery of the purple catspaw, Epioblasma obliquata obliquata, in Killbuck Creek, Coshocton County, OH, is reported. This subspecies of unionid mollusc was thought to have been extirpated from the state in the mid to late 1800s and was known only from two nonreproductive populations in Kentucky and Tennessee. The mussel was thought to be on the verge of extinction. Fifteen living and 23 dead specimens of this subspecies were collected in September 1994 from Killbuck Creek. This is the largest known population of this rare subspecies and it is the only known population to currently support breeding individuals. It is threatened by soil erosion resulting from agricultural land-use practices such as clearing of the stream banks for farm fields and cattle grazing and by muskrat predation

SPATIAL CO-MANAGEMENT OF INDONESIAN FLOODPLAIN RIVER FISHERIES

An interdisciplinary investigation was nrade on the mechanisms underlying the development of local manugement systems for floodplain river fisheries in Sumater

Single-photon-level sub-Doppler pump-probe spectroscopy of rubidium

We propose and demonstrate pump-probe spectroscopy of rubidium absorption which reveals the sub-Doppler hyperfine structure of the $^{5}$S$_{1/2} \leftrightarrow$ $^{5}$P$_{3/2}$ (D2) transitions. The counter propagating pump and probe lasers are independently tunable in frequency, with the probe operating at the single-photon-level. The two-dimensional spectrum measured as the laser frequencies are scanned shows fluorescence, Doppler-broadened absorption dips and sub-Doppler features. The detuning between the pump and probe lasers allows compensation of the Doppler shift for all atomic velocities in the room temperature vapor, meaning we observe sub-Doppler features for all atoms in the beam. We detail a theoretical model of the system which incorporates fluorescence, saturation effects and optical pumping and compare this with the measured spectrum, finding a mean absolute percentage error of 4.17\%. In the future this technique could assist in frequency stabilization of lasers, and the single-photon-level probe could be replaced by a single photon source.Comment: 5 page paper, 4 page supplemental material. Comments welcom

Island resource exploitation by the ancient Maya during periods of climate stress, Ambergris Caye, Belize

Ancient Maya societies experienced a period of reorganisation and change in settlement patterns associated with social and climate instability at the end of the Classic period (750-1000 CE) and the subsequent Postclassic period (1200-1500 CE). Although it has been proposed that severe droughts and the breakdown of Classic political systems caused a migration of populations towards the coast, we have little evidence of the nature of land-use at coastal sites. Our understanding of subsistence on islands has been shaped by archaeological research indicating marine-based diets, with maize imported from the mainland. Here we provide, for the first time, palaeoecological proxy data that inform on ancient Maya land-use on an island site, located on Ambergris Caye, Belize. Using pollen and charcoal proxies, we present over 6000 years of environmental change and land-use history. Our reconstruction reveals evidence of cultivation, beginning at 2900 BCE and culminating during the Postclassic Period. We demonstrate that periods of higher land-use intensity correlate with climate instability, which corroborates archaeological evidence of migration to coastal locations. We hypothesize that the diverse marine and terrestrial environments of the island provided sustainable resources for the mainland Maya to use during times of both political and climatic stress