24,028 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
SIMMUNE, a tool for simulating and analyzing immune system behavior
We present a new approach to the simulation and analysis of immune system
behavior. The simulations that can be done with our software package called
SIMMUNE are based on immunological data that describe the behavior of immune
system agents (cells, molecules) on a microscopial (i.e. agent-agent
interaction) scale by defining cellular stimulus-response mechanisms. Since the
behavior of the agents in SIMMUNE can be very flexibly configured, its
application is not limited to immune system simulations. We outline the
principles of SIMMUNE's multiscale analysis of emergent structure within the
simulated immune system that allow the identification of immunological contexts
using minimal a priori assumptions about the higher level organization of the
immune system.Comment: 23 pages, 10 figure
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
Downright Sexy: Verticality, Implicit Power, and Perceived Physical Attractiveness
Grounded theory proposes that abstract concepts (e.g., power) are represented by perceptions of vertical space (e.g., up is powerful; down is powerless). We used this theory to examine predictions made by evolutionary psychologists who suggest that desirable males are those who have status and resources (i.e., powerful) while desirable females are those who are youthful and faithful (i.e., powerless). Using vertical position as an implicit cue for power, we found that male participants rated pictures of females as more attractive when their images were presented near the bottom of a computer screen, whereas female participants rated pictures of males as more attractive when their images were presented near the top of a computer screen. Our results support the evolutionary theory of attraction and reveal the social-judgment consequences of grounded theories of cognition
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
Bremsstrahlung Pair Production In Relativistic Heavy Ion Collision
We calculate production of electron- and muon-pairs by the bremsstrahlung
process in hadron collisions and compare it with the dominant two-photon
process. Results for the total cross section are given for proton-proton and
heavy-ion collisions at energies of the Relativistic Heavy Ion Collider (RHIC)
and the Large Hadron Collider (LHC).Comment: 6 pages, Latex, 9 figures using epsf-style. Accepted for publication
in Z. Phys.
Monadicity of the Bousfield-Kuhn functor
We consider the localization of the -category of spaces at the -periodic equivalences, the case being rational homotopy theory. We prove that this localization is for equivalent to algebras over a certain monad on the -category of -local spectra. This monad is built from the Bousfield--Kuhn functor
Development and study of chemical vapor deposited tantalum base alloys
A technique for the chemical vapor deposition of alloys was developed. The process, termed pulsing, involves the periodic injection of reactant gases into a previously-evacuated reaction chamber where they blanket the substrate almost instantaneously. Formation of alternating layers of the alloy components and subsequent homogenization allows the formation of an alloy of uniform composition with the composition being determined by the duration and relative numbers of the various cycles. The technique has been utilized to produce dense alloys of uniform thickness and composition (Ta- 10 wt % W) by depositing alternating layers of Ta and W by the hydrogen reduction of TaCl5 and WCl6. A similar attempt to deposit a Ta - 8 wt % W - 2 wt% Hf alloy was unsuccessful because of the difficulty in reducing HfCl4 at temperatures below those at which gas phase nucleation of Ta and W occurred
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