Browsing by Author "Dewan, Ramita"
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Item A Biofuel-Capable Wetland with Optimal Nitrate Uptake from Chesapeake Bay Waters Affected by Agricultural Runoff(2011) Agarwal, Arsh; Bradford, Allie; Cheng, Kerry; Dewan, Ramita; Disla, Enrique; Goodley, Addison; Lim, Nathan; Liu, Lisa; Place, Lucas; Ramadorai, Raevathi; Shankar, Jaishri; Wellen, Michael; Ye, Diane; Yu, Edward; Tilley, David; Kackley, RobertHarmful algal blooms caused by nitrates and phosphates negatively affect estuarine ecosystems, such as the Chesapeake Bay. These blooms release toxins and block sunlight needed for submerged aquatic vegetation, creating hypoxic areas of the Bay. Artificial wetlands have been utilized to reduce the amount of nitrate pollution. This project will test the Typha latifolia (cattail), Panicum virgatum (switchgrass), and Schoenoplectus validus (soft-stem bulrush) for denitrification potential. In order to amplify the differences between the plants, we will use a carbon-based denitrification factor to be found through testing. We plan to use the ANOVA test in order to determine the significance of our findings. Based on our data, future environmental groups can better choose the species they will plant in artificial wetlands.Item Interactive Effects of Plant Species and Organic Carbon on Nitrate Removal in Chesapeake Bay Treatment Wetlands(2013) Agarwal, Arsh; Bradford, Allie; Cheng, Kerry; Dewan, Ramita; Disla, Enrique; Goodley, Addison; Lim, Nathan; Liu, Lisa; Place, Lucas; Ramadorai, Raevathi; Shankar, Jaishri; Wellen, Michael; Ye, Diane; Yu, Edward; Tilley, David R.Nitrate from agricultural runoff are a significant cause of algal blooms in estuarine ecosystems such as the Chesapeake Bay. These blooms block sunlight vital to submerged aquatic vegetation, leading to hypoxic areas. Natural and constructed wetlands have been shown to reduce the amount of nitrate flowing into adjacent bodies of water. We tested three wetland plant species native to Maryland, Typha latifolia (cattail), Panicum virgatum (switchgrass), and Schoenoplectus validus (soft-stem bulrush), in wetland microcosms to determine the effect of species combination and organic amendment on nitrate removal. In the first phase of our study, we found that microcosms containing sawdust exhibited significantly greater nitrate removal than microcosms amended with glucose or hay at a low nitrate loading rate. In the second phase of our study, we confirmed that combining these plants removed nitrate, although no one combination was significantly better. Furthermore, the above-ground biomass of microcosms containing switchgrass had a significantly greater percentage of carbon than microcosms without switchgrass, which can be studied for potential biofuel use. Based on our data, future environmental groups can make a more informed decision when choosing biofuel-capable plant species for artificial wetlands native to the Chesapeake Bay Watershed.Item Mice Lacking M1 and M3 Muscarinic Acetylcholine Receptors Have Impaired Odor Discrimination and Learning(Frontiers, 2017-02-02) Chan, Wilson; Singh, Sanmeet; Keshav, Taj; Dewan, Ramita; Eberly, Christian; Maurer, Robert; Nunez-Parra, Alexia; Araneda, Ricardo C.The cholinergic system has extensive projections to the olfactory bulb (OB) where it produces a state-dependent regulation of sensory gating. Previous work has shown a prominent role of muscarinic acetylcholine (ACh) receptors (mAChRs) in regulating the excitability of OB neurons, in particular the M1 receptor. Here, we examined the contribution of M1 and M3 mAChR subtypes to olfactory processing using mice with a genetic deletion of these receptors, the M1-/- and the M1/M3-/- knockout (KO) mice. Genetic ablation of the M1 and M3 mAChRs resulted in a significant deficit in odor discrimination of closely related molecules, including stereoisomers. However, the discrimination of dissimilar molecules, social odors (e.g., urine) and novel object recognition was not affected. In addition the KO mice showed impaired learning in an associative odor-learning task, learning to discriminate odors at a slower rate, indicating that both short and long-term memory is disrupted by mAChR dysfunction. Interestingly, the KO mice exhibited decreased olfactory neurogenesis at younger ages, a deficit that was not maintained in older animals. In older animals, the olfactory deficit could be restored by increasing the number of new born neurons integrated into the OB after exposing them to an olfactory enriched environment, suggesting that muscarinic modulation and adult neurogenesis could be two different mechanism used by the olfactory system to improve olfactory processing.