1,850 research outputs found
Notes on the Life History of \u3ci\u3ePotamanthus Myops\u3c/i\u3e in Southeastern Michigan (Ephemeroptera: Potamanthidae)
Naiads of the mayfly Potamanthus myops were collected six times over a one year period from the Huron River to obtain some information on their natural history. Contrary to other Ephemeroidea, myops was never collected below the substrate surface, but was usually found on the underside of stones. The immature mayflies were measured and their length plotted for each collection period. The results support the hypothesis that the majority of myops requires two years to mature
A New Method for Exposing Deposit Feeders to Contaminated Sediments for Food Chain Studies
(excerpt)
The ubiquity and refractory nature of certain organic compounds, such as chlorinated pesticides and polychlorinated biphenyls (PCB\u27s), results in their accumulation in aquatic sediments (Holdrinet et al. 1978, Peck et al. 1980, Wang et al. 1979). Their continuous release from this reservoir through physico-chemical and biogenic processes to the overlying water column results in the accumulation of xenobiotic compounds in the food chain
Intraspecific Variation in Taxonomic Characteristics of the Mayfly \u3ci\u3ePotamanthus Myops\u3c/i\u3e (Walsh)
Data collected from an ecological study of the mayfly Potamanthus rnyops (Walsh) in Michigan showed intraspecific variability in taxonomic characteristics that have been employed by previous investigators for species separation. Nymphal dorsal maculation patterns varied considerably within a single population. Also, the ratio of mandibular tusk length to head length increased with successive nymphal instars. Certain adult taxonomic characteristics, particularly relative male imago eye size and distance of separation, were either too poorly defined or too variable to be conclusive in species identification
A Modified Method for Reading Midges (Diptera: Chironomidae)
A small scale rearing chamber that provides a continuous source of different life stages of Glyptotendipes barbipes Staeger for bioassay studies was developed. A modified glass aquarium containing a substrate of shredded paper hand towels and artificial medium was employed. The amount of protein fed to the larvae can be used to trigger peak emergence, oviposition, and the rate of maturation. Fifty-three egg masses were sampled and 68% were fertile. Ninety-five percent of these hatched and 85% emerged as adults
Effects of Salmon Spawning Activity on Macroinvertebrates in a Small Michigan Stream
Density and composition of macroinvertebrate populations were examined prior to and during the migration and spawning of coho and chinook salmon in a small stream in Michigan. Data gathered from bottom samples indicated that disruption of substrate in the experimental area resulted in a significant decrease in the numbers and species of the macroinvertebrate community. This reduction of invertebrates can create a severe stress on native trout populations
(2S)-Methyl 2-(p-toluenesulfonamido)propanoate
The enantiomerically pure title compound, C11H15NO4S, contains a pyramidal N atom with an S—N bond length of 1.6262 (8) Å. In the crystal, molecules are linked to form chains parallel to the a axis by the hydrogen bond from NH to the carbonyl oxygen. C—H⋯O interactions are also present
Implications of Chemical-Based Effluent Regulations in Assessing DNA Damage in Fathead Minnows ( Pimephales promelas ) When Exposed to Metal Plating Wastewater
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42356/1/128-64-5-716_00640716.pd
Clinical review: Influence of vasoactive and other therapies on intestinal and hepatic circulations in patients with septic shock
The organs of the hepatosplanchnic system are considered to play a key role in the development of multiorgan failure during septic shock. Impaired oxygenation of the intestinal mucosa can lead to disruption of the intestinal barrier, which may promote a vicious cycle of inflammatory response, increased oxygen demand and inadequate oxygen supply. Standard septic shock therapy includes supportive treatment such as fluid resuscitation, administration of vasopressors (adrenergic and nonadrenergic drugs), and respiratory and renal support. These therapies may have beneficial or detrimental effects not only on systemic haemodynamics but also on splanchnic haemodynamics, at both the macrocirculatory and microcirculatory levels. This clinical review focuses on the splanchnic haemodynamic and metabolic effects of standard therapies used in patients with septic shock, as well as on the recently described nonconventional therapies such as vasopressin, prostacyclin and N-acetyl cysteine
Periphytic oxygen production in outdoor experimental channels
The contribution of periphytic oxygen was quantified in outdoor artificial streams. A factorial design was employed to determine the effect of stream velocity and light on periphytic growth, measured as chlorophyll [alpha]. Results showed that periphytic oxygen production can be estimated by the equation: =0.91 x 10-3 x Light Intensity (1x) + 0.061 for light intensities to 5000 ft-candles (53,800 lx). Stream velocity was found to be statistically insignificant in affecting oxygen production, but was a factor in periphyton accural and species composition. Gross oxygen production exceeded respiration by a factor of three.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25029/1/0000456.pd
Lethal and Sublethal Effects of Azulene and Longifolene to Microtox®, Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42354/1/128-58-2-268_58n2p268.pd
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