MULTISPECIES MODELING FOR ADAPTIVE MANAGEMENT OF HORSESHOE CRABS AND RED KNOTS IN THE DELAWARE BAY

Abstract Adaptive management requires that predictive models be explicit and transparent to improve decisions by comparing management actions, directing further research and monitoring, and facilitating learning. The rufa subspecies of red knots (Calidris canutus rufa), which has recently exhibited steep population declines, relies on horseshoe crab (Limulus polyphemus) eggs as their primary food source during stopover in Delaware Bay during spring migration. We present a model with two different parameterizations for use in the adaptive management of horseshoe crab harvests in the Delaware Bay that links red knot mass gain, annual survival, and fecundity to horseshoe crab dynamics. The models reflect prevailing hypotheses regarding ecological links between these two species. When reported crab harvest from 1998 to 2008 was applied, projections corresponded to the observed red knot population abundances depending on strengths of the demographic relationship between these species. We compared different simulated horseshoe crab harvest strategies to evaluate whether, given this model, horseshoe crab harvest management can affect red knot conservation and found that restricting harvest can benefit red knot populations. Our model is the first to explicitly and quantitatively link these two species and will be used within an adaptive management framework to manage the Delaware Bay system and learn more about the specific nature of the linkage between the two species.     

12 W高功率高可靠性915 nm半导体激光器设计与制作

本文设计并制作了一种高效率、高可靠性的915 nm半导体激光器。半导体激光器是光纤激光器的关键部件,为了最大限度地提高器件的电光转换效率,在设计上采用双非对称大光腔波导结构,同时对量子阱结构、波导结构、掺杂以及器件结构进行了系统优化。器件模拟表明,在25℃环境温度下,器件的最高电光转换效率达到67%。采用金属有机气相沉积(MOCVD)法进行材料生长,随后制备了发光区域宽度为95μm、腔长为4.8 mm的激光芯片。测试表明,封装后器件的效率以及其它参数指标达到国际先进水平,在室温下阈值电流为1 A,斜率效率为1.18 W/A,最高电光转换效率达66.5%,输出功率12 W时,电光转换效率达到64.3%,测试结果与器件理论模拟高度吻合。经过约6 000 h的寿命加速测试,器件功率没有出现衰减,表明制作的高功率915 nm激光芯片具有很高的可靠性。     

Optical Aspartame Biosensor Based on Bienzyme Immobilisation on Egg Shell Membrane

Aspartame is a widely used artificial sweetener in many low calorie foods and beverages. Determination of its concentration in foodstuff is important as aspartame is a relatively expensive material. A novel optical biosensor for the determination of aspartame in beverage based on a bienzyme system is presented. An aspartame biosensor was fabricated employing a bienzyme system composed of chymotrypsin and alcohol oxidase immobilised onto a egg shell membrane and an oxygen-sensitive optode membrane as the transducer. The detection schemes involve the enzymatic reactions of aspartame leading to the depletion of oxygen level of the medium with concomitant enhancement of the fluorescence intensity of the oxygen-sensitive membrane.     

ChemInform Abstract: Structural and Thermal Properties of the Tetragonal Cobalt Manganese Spinels MnxCo3-xO4 (1.4 < x < 2.0).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Infrared Spectra of Boron Atom-Ammonia Reaction Products in Solid Argon.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.