616 research outputs found
Noise and Equivalent Circuit of Double Injection
Measurements of the high‐frequency noise of a silicon double‐injection diode result in 〈i^2〉 = α⋅4kT(1/r)Δf with α=1.04 and in agreement with the literature. A new interpretation demands Nyquist noise with α≡1 in these devices at high frequencies. This is in accord with an equivalent circuit derived for the double‐injection process. Speculations are made on the general validity of Nyquist noise in nonlinear devices at high frequencies. In addition, generation‐recombination noise is suggested as the prime source of the low‐frequency noise
An Updated Checklist to the Non-biting Midges (Chironomidae) of Illinois
The Chironomidae, or non-biting midges, of Illinois have been untreated since the early 20th century, and the high level of taxonomic flux in the family necessitates an update, particularly for a group with importance as bio-indicators of freshwater ecosystem health. Herein, 181 species of Chironomidae in 76 genera are recorded from the state of Illinois. Each species entry is annotated with the first Illinoisan record of the species. Two genera, Brillia Kieffer, 1913 and Prodiamesa Kieffer, 1906, are recorded for the first time from Illinois, as are three species: Xenochironomus xenolabis (Kieffer in Thienemann and Kieffer, 1916) (Chironominae); Brillia flavifrons (Johannsen, 1905) (Orthocladiinae); and Prodiamesa olivacea (Meigen, 1818) (Prodiamesinae)
Does the quark cluster model predict any isospin two dibaryon resonance?
We analyze the possible existence of a resonance in the channel
with isospin two by means of nucleon- interactions based on the
constituent quark model. We solve the bound state and the scattering problem
using two different potentials, a local and a non-local one. The non-local
potential results to be the more attractive, although not enough to generate
the experimentally predicted resonance.Comment: 9 pages in Latex (revtex), 2 eps figures available under reques
Biotic Integrity of macroinvertebrate communities along the I-294 corridor
Sampled macroinvertebrates following ILEPA protocol at 7 sites in August–September 2015 in the I-294 corridor and calculated biotic integrity metrics
•
Assessed sites based on the Qualitative Stream Habitat Assessment Procedure (SHAP)
•
Measured physical (width, depth, velocity) and chemical (pH, conductivity, salinity, total dissolved solids) characteristics
•
Habitat assessment showed impairment compared to Illinois reference conditions at all sites
•
Macroinvertebrate Index of Biotic Integrity rated 6 sites as “Poor” and one as “Fair”
▷▷
Total taxa richness ranged from 10 to 19 across sites
▷▷
4 of the 7 sites had no EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa
▷▷
No Plecoptera (stoneflies) were collected at any siteIllinois State Toll Highway Authorityunpublishednot peer reviewe
Hepatic cell loss and proliferation induced by N-2-fluorenylacetamide, diethylnitrosamine, and aflatoxin B1 in relation to hepatoma induction.
Three hepatic carcinogens (aflatoxin B1, diethylnitrosamine (DEN) and N-2-fluorenylacetamide (FAA)) were compared for carcinogenicity, early cell toxicity and parenchymal cell proliferation. The carcinogens were administered to rats for 15 weeks as follows: aflatoxin B1, 1 in 10(6) in pelleted food; DEN, 2 in 10(5) in drinking water; FAA, 3 in 10(4) in pelleted food. The loss of prelabelled DNA and the [H3] TdR pulse-labelling indices (LI) of parenchymal and nonparenchymal cells were determined at various times during the period of carcinogen availability. On a molar basis, aflatoxin B1 was 90 times as carcinogenic as FAA and 24 times as carcinogenic as DEN. However, for about equal magnitudes of hepatic cell proliferation and loss, aflatoxin B1 was the least potent carcinogen. For a given level of carcinogenicity, FAA was more potent than DEN in causing loss of hepatic DNA and in increasing the parenchymal cell labelling index. DEN and aflatoxin B1 produced about the same degree of DNA loss and parenchymal cell labelling, but the former was a more potent carcinogen. When carcinogenicity was compared for approximately equal levels of early hepatic cell destruction and proliferation, the 3 chemicals in the present study could be ranked in descending order of potency as DEN, FAA and aflatoxin B1
Right to Serve, Right to Lead: Lives and Legacies of the USCT
This is a catalog for an exhibit that follows the evolution of African-American participation in the Civil War, from slaves, to contrabands, to soldiers of the United States Colored Troops (USCT), as well as the lives of black veterans beyond the war, and their ultimate military and social legacy. Using a variety of period items, it creates a narrative that stretches from the Antebellum Period to the current day. In doing so, the exhibit shows how black sacrifice on the battlefield redefined the war\u27s purpose throughout the divided nation, how Jim Crowe suppressed the memory of black participation after Reconstruction, and how the illustrious African-American military tradition left by the USCT endures to this day in their modern heirs
Search for Low Mass Exotic mesonic structures. Part I: experimental results
Recently, several papers discussed on the existence of a low mass new
structure at a mass close to M=214.3 MeV. It was suggested that the
disintegration: pP, P
proceeds through an intermediate particle P having such mass. The present
work intends to look at other new or available data, in order to observe the
eventual existence of small narrow peaks or shoulders in very low mesonic
masses. Indeed narrow structures were already extracted from various data in
dibaryons, baryons and mesons (at larger masses that those studied here).Comment: 7 pages 11 figure
Self-similarity of fluid residence time statistics in a turbulent round jet
Fluid residence time is a key concept in the understanding and design of chemically reacting flows. In order to investigate how turbulent mixing affects the residence time distribution within a flow, this study examines statistics of fluid residence time from a direct numerical simulation (DNS) of a statistically stationary turbulent round jet with a jet Reynolds number of 7290. The residence time distribution in the flow is characterised by solving transport equations for the residence time of the jet fluid and for the jet fluid mass fraction. The product of the jet fluid residence time and the jet fluid mass fraction, referred to as the mass-weighted stream age, gives a quantity that has stationary statistics in the turbulent jet. Based on the observation that the statistics of the mass fraction and velocity are self-similar downstream of an initial development region, the transport equation for the jet fluid residence time is used to derive a model describing a self-similar profile for the mean of the mass-weighted stream age. The self-similar profile predicted is dependent on, but different from, the self-similar profiles for the mass fraction and the axial velocity. The DNS data confirm that the first four moments and the shape of the one-point probability density function of mass-weighted stream age are indeed self-similar, and that the model derived for the mean mass-weighted stream-age profile provides a useful approximation. Using the self-similar form of the moments and probability density functions presented it is therefore possible to estimate the local residence time distribution in a wide range of practical situations in which fluid is introduced by a high-Reynolds-number jet of fluid
- …