Extraadrenal adrenaline formation by two separate enzymes

Summary Adrenaline (A) is synthesized in the adrenal medullae by the enzyme phenylethanolamine-N-methyltransferase (PNMT). After surgical removal of the adrenal medullae tissue A levels ranged from 22% of control in the heart to 125% of control in the liver. Use of a novel assay to measure tissue A formation revealed that many tissues can synthesize A using PNMT and another enzyme that N-methylates both noradrenaline and dopamine. These enzymes are non-neuronal, inducible and synthesize a major fraction of tissue and urine A.     

高级动力学

高级动力学可以对动力学的分析工具作宽广且详尽的描写，可以讨论不同的强度和弱点，特别强调怎样才能彻底解决问题的技能。本书开始详尽评述矢量动力学，继而瞄准拉格朗日和哈密尔顿两方程以及诸如冲激响应、微分形式和可积性等不熟悉课题，还描述计算效能上超过传统经典法，特别当用于复杂的动力系统时效果更显著的重大改进。数值分析处理包括讨论数值稳定性和约束稳定两方面。本教科书每章附有不少工作例子和课后的思考问题。     

A heuristic algorithm to solve the task partition problem in MDOCEM

This paper examines task partition problem in a Multiagent-based Distributed Open Computing Environment Model (MDOCEM). We first present a formal method to describe the task partition problem, then give a heuristic algorithm to solve the task partition problem that gives an approximate optimum solution. Foundation item: Supported partially by the National 863 High Technology Project (863-306-05-01-1B) Biography: He Yan-xiang (1952-), male, Professor, Research interests include distributed OS and distributed information processing, distributed software engineering, parallel compiler.     

The auroral footprint of Enceladus on Saturn

Although there are substantial differences between the magnetospheres of Jupiter and Saturn, it has been suggested that cryovolcanic activity at Enceladus could lead to electrodynamic coupling between Enceladus and Saturn like that which links Jupiter with Io, Europa and Ganymede. Powerful field-aligned electron beams associated with the Io-Jupiter coupling, for example, create an auroral footprint in Jupiter's ionosphere. Auroral ultraviolet emission associated with Enceladus-Saturn coupling is anticipated to be just a few tenths of a kilorayleigh (ref. 12), about an order of magnitude dimmer than Io's footprint and below the observable threshold, consistent with its non-detection. Here we report the detection of magnetic-field-aligned ion and electron beams (offset several moon radii downstream from Enceladus) with sufficient power to stimulate detectable aurora, and the subsequent discovery of Enceladus-associated aurora in a few per cent of the scans of the moon's footprint. The footprint varies in emission magnitude more than can plausibly be explained by changes in magnetospheric parameters--and as such is probably indicative of variable plume activity.     

A non representationalist view of model explanation

In this paper, I examine two idealized models in astrophysics, with the aim of showing that the idealizations in these models play an important explanatory role. I argue, against many representationalists, that it is because of the idealizations in these models, rather than in spite of them, that the models turn out to have explanatory power. In many cases, this claim can be extended to the use of idealized models in the sciences more generally, and thus it gives important insight into the nature of model explanation.     

Presettlement vegetation of part of northwestern Moffat County, Colorado, described from remnants

A general botanical inventory of a part of northwestern Moffat County, Colorado, resulted in the location of “ remnants ” of the presettlement vegetation spectrum that are largely unaltered by grazing, logging, or other recent human - related land uses. The 69 samples taken from these remnants were classified into 22 plant associations. Composition, structure, environmental location, geographical range, and response to disturbance are discussed for each association, and a photograph of each is presented. Seven of the 22 associations are apparently restricted to the study area. Restricted associations occur in the more extreme environments of the study area, such as on calcareous substrata or very xeric sites. More mesic sites along ephemeral creeks, on north - facing slopes, or on sandstones support plant associations that have much wider ranges, many of them extending across the northern Great Basin.        

New records and species of Tetranychidae and Tenuipalpidae (Acarina) from Utah and Idaho

Twenty-three species of spider mites (Tetranychidae) are recognized for Utah and Idaho; three of these are described as new: Bryobia neoribis, Pseudobryobia knowltoni, and Schizotetranychus agropyron. Eleven species of Tenuipalpidae are recorded.     

Variation in the incidence of botfly larvae ( Cuterebra ) in two sympatric species of Peromyscus in northern Colorado

Differences in botfly parasitism were observed in the sympatric species Peromyscus maniculatus and P. difficilis in northern Colorado. The overall incidence of infection was 13.7 percent in P. maniculatus and only 0.6 percent in P. difficilis. The incidence of parasitism was affected markedly by trapping locality and by month of capture.     

Habitat Preference and diurnal use among Greater Sandhill Cranes

We examined patterns of habitat use by Greater Sandhill Cranes ( Grus canadensis tabida ) in the Intermountain West, April-October 1991-92, to determine whether cranes exhibited a specific preference for crops, fields, and areas within a field. This information will help farmers and wildlife managers direct nonlethal control methods to the sites where crane damage is most likely to occur. We conducted surveys along two 37-km transects weekly in Cache Valley, Utah, and biweekly in Bear River Valley, Rich County, Utah, and Lincoln County, Wyoming. We recorded 5814 cranes in 662 separate groups. Most were located in pasture/hay (34%), small grain (39%), alfalfa (9%), plowed (9%), fallow (4%), or corn (1%) fields. An index of feeding activity for each field and habitat type suggested cranes fed at approximately the same rate in each field and habitat type. Crane diurnal activity patterns during summer and fall revealed that grainfields were used heavily throughout the day.     

New species and new records of North America Pityophthorus (Coleoptera: Scolytidae), Part VI. The Lautus group

Four new species of Mexican Pityophthorus in the Lautus group are described: P. indefessus (Jalisco), P. inhabilis (Guerrero), P. tutulus (Veracruz), and P. vegrandis (Quintana Roo) and a new locality record is given for P. corruptus Wood.