1,619 research outputs found
Field Recognition of Adult \u3ci\u3eAcentrella\u3c/i\u3e and \u3ci\u3eHeterocloeon\u3c/i\u3e (Ephemeroptera: Baetidae)
The highly developed anterior process of the mesothorax, is described as a useful field character for identifying adults of Acentrella and Heterocloeon in the Nearctic. This presumed adult synapomorphy suggests a sister relation- ship of the two genera
Gleaning on Coreidae (Heteroptera) by \u3ci\u3eTachopteryx Thoreyi\u3c/i\u3e (Odonata: Petaluridae)
(excerpt)
Tachopteryx thoreyi (Hagen in Selys) is an uncommon or rare, fen and seep dwelling dragonfly noted for its large size, restricted habitat requirements, and characteristic habit of perching on tree trunks
Barbaetis: A New Genus of Eastern Nearctic Mayflies (Ephemeroptera: Baetidae)
The new genus Barbaetis Waltz and McCafferty, and new species Barbaetis benfieldi Kennedy are described from larvae collected from the New River, Virginia. Barbaetis is easily told from Baetis by the presence of procoxal osmobranchia. Cladistics of B. benfieldi, related Pseudocloeon species, and the lutheri and pavidus complexes of Baetis are presented and indicate the need for further taxonomic revision. The habitat of B. benfieldi is described in terms of several ecological parameters. The new species demonstrates a univoltine life history with postembryonic development restricted to a short springtime period
\u3ci\u3eCallibaetis Pretiosus\u3c/i\u3e (Ephemeroptera: Baetidae) From Pennsylvania: New Distribution Record
Larvae of Callibaetis pretiosus were collected from a wet-weather pool in Monroe County, Pennsylvania. This record represents a significant northward increase in the known distribution of this species which had previously been reported only from Alabama, Florida, Georgia, North CarolIna, Tennessee, Texas, and Virginia
New Synonomy in \u3ci\u3eHypogastrura\u3c/i\u3e (Collembola: Hypogastruridae)
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In the course of faunistic studies of Indiana Collembola, seasonal occurrences of the two species Hypogastrura packardi (Folsom), 1902 and H. notha (MacNamara), 1922 were found to exhibit seasonal dimorphism and population dynamics similar to those patterns observed in cyclomorphic species previously reported in literature (Leinaas 1981 a,b)
South Carolina marine recreational fishery survey, 1990
One of the principal responsibilities of the Marine Resources Division is management of recreational fisheries. Effective management requires an extensive data base on both the resources and their usage. MRD's Fisheries Statistics Program is primarily responsible for the collection, compilation, analysis, and distribution of fishery-dependent information for the marine recreational fisheries. This report describes procedures and results of these surveys for 1990
Globalising assessment: an ethnography of literacy assessment, camels and fast food in the Mongolian Gobi
What happens when standardised literacy assessments travel globally? The paper presents an ethnographic account of adult literacy assessment events in rural Mongolia. It examines the dynamics of literacy assessment in terms of the movement and re-contextualisation of test items as they travel globally and are received locally by Mongolian respondents. The analysis of literacy assessment events is informed by Goodwin’s ‘participation framework’ on language as embodied and situated interactive phenomena and by Actor Network Theory. Actor Network Theory (ANT) is applied to examine literacy assessment events as processes of translation shaped by an ‘assemblage’ of human and non-human actors (including the assessment texts)
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Cortical oscillatory activity is critical for working memory as revealed by deficits in early-onset schizophrenia
Impairments in working memory (WM) are a core cognitive deficit in schizophrenia. Neurophysiological models suggest that deficits during WM maintenance in schizophrenia may be explained by abnormalities in the GABAergic system, which will lead to deficits in high-frequency oscillations. However, it is not yet clear which of the three WM phases (encoding, maintenance, retrieval) are affected by dysfunctional oscillatory activity. We investigated the relationship between impairments in oscillatory activity in a broad frequency range (3–100 Hz) and WM load in the different phases of WM in 14 patients with early-onset schizophrenia and 14 matched control participants using a delayed matching to sample paradigm.
During encoding, successful memorization was predicted by evoked theta, alpha, and beta oscillatory activity in controls. Patients showed severe reductions in the evoked activity in these frequency bands. During early WM maintenance, patients showed a comparable WM load-dependent increase in induced alpha and gamma activity to controls. In contrast, during the later maintenance phase, patients showed a shift in the peak of induced gamma activity to the lower WM load conditions. Finally, induced theta and gamma activity were reduced in patients during retrieval.
Our findings suggest that the WM deficit in schizophrenia is associated with impaired oscillatory activity during all phases of the task and that the cortical storage system reaches its capacity limit at lower loads. Inability to maintain oscillatory activity in specific frequency bands could thus result in the information overload that may underlie both cognitive deficits and psychopathological symptoms of schizophrenia
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Advances in the simulation of toroidal gyro Landau fluid model turbulence
The gyro-Landau fluid (GLF) model equations for toroidal geometry have been recently applied to the study ion temperature gradient (ITG) mode turbulence using the 3D nonlinear ballooning mode representation (BMR). The present paper extends this work by treating some unresolved issues conceming ITG turbulence with adiabatic electrons. Although eddies are highly elongated in the radial direction long time radial correlation lengths are short and comparable to poloidal lengths. Although transport at vanishing shear is not particularly large, transport at reverse global shear, is significantly less. Electrostatic transport at moderate shear is not much effected by inclusion of local shear and average favorable curvature. Transport is suppressed when critical E{times}B rotational shear is comparable to the maximum linear growth rate with only a weak dependence on magnetic shear. Self consistent turbulent transport of toroidal momentum can result in a transport bifurcation at suffciently large r/(Rq). However the main thrust of the new formulation in the paper deals with advances in the development of finite beta GLF models with trapped electron and BMR numerical methods for treating the fast parallel field motion of the untrapped electrons
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