Life History Attributes of Asian Carps in the Upper Mississippi River System

INTRODUCTION: The Upper Mississippi River (UMR) system starts at the confluence of the Ohio River at Cairo, Illinois, and serves as a conduit for many aquatic invasive species to enter the waterways of the central and northern interior of the United States, including the Great Lakes. One well-established group found in this waterway is the Asian carps including the common carp Cyprinus carpio, grass carp Ctenopharyngodon idella, and two recent invaders, the bighead car

Linking Adult Reproduction and Larval Density of Invasive Carp in a Large River

Identifying how temporal variation in the environment affects reproductive success of invasive alien species will aid in predicting future establishment and tracking dynamics of established populations. Asian carp Hypophthalmichthys spp. have become a nuisance in recent years in the Mississippi River basin. Their populations are apparently expanding, indicating favorable conditions for reproduction. During 2004 and 2005, we quantified mean density of Asian carp larvae, mean monthly gonadosomatic index (GSI) of adult males and females, and number of eggs within mature females in the lower Illinois River, a major tributary of the Mississippi River. A flood (water velocity ≥ 0.7 m/s) and drought (\u3c0.2 m/s) occurred during apparent spawning in 2004 and 2005, respectively. During 2004, Asian carp larvae were found during 32% of sampling weeks; mean GSI and fecundity were relatively low for adults, probably reflecting partially spawned individuals and perhaps low reproductive investment. During the drought of 2005, larval stages were present during only one (5%) of the sampling weeks, whereas mean GSI and fecundity of adults were high through summer. Females resorbed their eggs instead of spawning during this year. Spawning conditions during low water periods appear to be unsuitable for Asian carps, inhibiting adult spawning and yielding few larvae. Spawning conditions during 2004 were better but still yielded low densities of larvae relative to native fishes. Reproduction in the lower Illinois River appears to be linked to river flow and its impact on adult spawning decisions, but conditions for strong year-class production (i.e., high larval densities) may be rarer than previously expected

Movement and Habitat Selection by Invasive Asian Carps in a Large River

We evaluated the habitat use and movements of 50 adult bighead carp Hypophthalmichthys nobilis and 50 silver carp H. molitrix by means of ultrasonic telemetry during spring–summer 2004 and 2005 to gain insight into the conditions that facilitate their establishment, persistence, and dispersal in the lower Illinois River (river kilometer 0–130). Movement and habitat use were monitored with stationary receivers and boat-mounted tracking. The relative availability of four macrohabitat categories (main channel, island side channel, channel border, and connected backwater) was quantified to determine selection; discriminant function analysis was used to evaluate changes in physical characteristics within each category. A flood pulse occurred in spring through early summer of 2004 but not 2005. Movement rates (km/week) of both species were positively correlated with flow but not with temperature. Including data from stationary receivers greatly increased estimates of daily movement. During low summer flow, both species typically selected channel borders and avoided the main channel and backwaters. Both species rarely occupied depths over 4 m, regardless of abiotic conditions. Flood pulses appear to trigger dispersal, while habitat use is only specific during low summer flow. Thus, movement prevention efforts (e.g., dispersal barriers) will require particular vigilance during late-winter or spring flooding, and controlled removal (e.g., harvest) should be directed toward selected habitats during summer

Novel internal measurements of ion cyclotron frequency range fast-ion driven modes

Novel internal measurements and analysis of ion cyclotron frequency range fast-ion driven modes in DIII-D are presented. Observations, including internal density fluctuation (˜n) measurements obtained via Doppler backscattering, are presented for modes at low harmonics of the ion cyclotron frequency localized in the edge. The measurements indicate that these waves, identified as coherent ion cyclotron emission (ICE), have high wave number, k⊥ρfast1, consistent with the cyclotron harmonic wave branch of the magnetoacoustic cyclotron instability, or electrostatic instability mechanisms. Measurements show extended spatial structure (at least ∼1/6 the minor radius). These edge ICE modes undergo amplitude modulation correlated with edge localized modes (ELM) that is qualitatively consistent with expectations for ELM-induced fast-ion transport

Effects of Different Levels of Echinostoma caproni Miracidial Dose on Glucose and Maltose Composition of Biomphalaria glabrata Snails as Determined by High Performance Thin-Layer Chromatography-Densitometry

The effects of 5, 25, and 40 Echinostoma caproni miracidia on the sugar content of young adult and mature adult Biomphalaria glabrata were studied using high performance thin layer chromatography (HPTLC)-densitometry. Analysis was done on the snail’s digestive gland gonad complex (DGG) at two and four weeks postmiracidial exposure. The sugars were extracted from the DGG using 70% ethanol and analyzed on silica gel HPTLC plates with a preadsorbent zone using 1-butanol-glacial acetic acid-diethyl ether-deionized water (27:18:5:3) mobile phase. The separated bands were then detected using alpha-naphthol-sulfuric reagent and quantified by densitometry at 515 nm. Significant differences were found in the maltose content between two and four weeks post exposure for both age groups. Additionally, significantly lower maltose and glucose levels were observed in the high exposure groups of both ages

Ion cyclotron emission on the DIII-D tokamak

Diagnosis of the fast ion population, which is necessary for heating but can drive dangerous instabilities, is crucial in achieving and maintaining a burning plasma regime. Present fast ion diagnostic methods tend to rely on delicate components unlikely to survive in a reactor environment, motivating exploration into alternative diagnostic methods. One candidate, the subject of this thesis, entails measurement of collective ion cyclotron emission (ICE) spectra via robust magnetic pickup loops integrated with the first wall, making it potentially compatible with ITER and other reactor-relevant devices [116, 69]. ICE, distinct from thermal electron cyclotron emission, manifests as narrowband peaks at harmonics of the ion cyclotron frequency $f_{ci}$ and is generally localized near the core or the edge of the plasma. These modes have been observed to be sensitive to the fast ion population, be they introduced by auxiliary heating systems or fusion products. However, the connection between observed ICE spectra and the fast ion population has not been sufficiently established, meriting diagnostic upgrades and dedicated experiments.This work aims to characterize ICE mode structure and fine-scale phenomena in L- and H-mode plasmas on DIII-D using the ICE diagnostic, which was recently upgraded to include additional channels and consequently new measurement capabilities. In addition to basic frequency and amplitude information, measurements of mode polarization at the plasma edge, amplitude as measured at the centerpost and outer wall of the machine, and toroidal mode number are now possible and will be demonstrated through this work. Additionally, mode sensitivity to the vacuum region, plasma shape, and particularly the fast ion distribution is explored. The detailed mode structure measurements and phenomenology presented in this work can be used to test and validate theoretical models en route to developing a more complete physical understanding of ICE, so that it can be leveraged as a passive fast ion diagnostic in future burning plasmas

Organophosphorus-Induced Delayed Neuropathology in the Rat.

Organophosphorus induced delayed neuropathy (OPIDN) is characterized by distinctive clinical and neuropathological features. The incipient clinical signs of gait disturbances and muscle weakness, are not manifest until 10-14 days post-dose. These signs of neurological impairment rapidly become exaggerated and result in paresis in severely affected animals. Axonal degeneration occurs in the long, large diameter fibers of both the central and peripheral nervous systems. Muscle spindles, in particular, have been shown to be the most sensitive neuronal targets in OPIDN. Chickens and cats have been the species of choice in OPIDN studies because of their obvious, consistent, and reproducible clinical responses to neurotoxic organophosphorus compounds. Unlike chickens and cats, rats do not display overt clinical signs of neurological impairment. Consequently, they have been considered to be a non-susceptible species. The biochemical initiating events which produce OPIDN involve phosphorylation and aging of a protein target site in nervous tissue. This protein has enzymatic properties and , therefore, has been termed "neurotoxic esterase" (NTE). Inhibition and aging of a threshold level of NTE inhibition ((GREATERTHEQ)70%) will predictably produce clinical signs of OPIDN in susceptible species. Therefore, it is anomalous that, although this critical level of NTE-inhibition is attained in the rat, overt clinical signs of OPIDN are not manifest. However, neuropathological examination using a silver-gold impregnating/cholinesterase staining method revealed striking axonal degeneration in rats treated with neurotoxic organophosphorus compounds. This neuropathological pattern correlated with NTE inhibition. While there was minimal axonal degeneration and sprouting at neuromuscular junctions, muscle spindles were severely affected. In this latter structure the sensory component was the principal target. Moreover, the neuropathology in muscle spindles was consistent with all of the established distinctive hallmarks of OPIDN for chicken and cat. Therefore, while it is interesting that rats do not display obvious clinical signs, the pathological evidence indicates that rats should be considered a susceptible species.Ph.D.NeurosciencesUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/161084/1/8621271.pd