Optimal Lossy Matching by Pareto Fronts

Although lossy matching is not a standard antenna matching technique, well-designed losses can facilitate wide-band matching of otherwise unmatchable antennas. The lossy matching designs developed in this paper are based on the Pareto front. These Pareto front computations permit the circuit designer to graphically select optimal gain-reflection tradeoffs for lossy matching, readily incorporate other lossless matching bounds, and provide a general approach to difficult wide-band matching problems.     

Negative Refraction Without Negative Index

Refraction of a microwave plane wave by a wedge with exact characterization of and is evaluated by a ray approach. Snell's Law is used for the lossless wedge, while exact formulations are used for the propagation constants and angle in the lossy wedge. The heavily lossy wedge produces negative refraction. Data are given on the loss factor that allows Snell refraction to be exactly reversed by lossy refraction, and the internal angle in the lossy wedge.     

An examination of the structure of leisure interests of college students, working-age adults, and retirees.

In this study, the authors investigated the extent to which factor and spatial structures of leisure interests (a) are similar to or distinct from the structure of vocational interests and (b) differ across 3 cohorts: college students (Mage = 19.6 years, SD = 1.23), working-age adults (Mage = 29.7, SD = 1.18), and retirees (Mage = 72.3 years, SD = 5.40). Factor analytic, multidimensional scaling, and covariance structure modeling strategies were used to assess the structure of leisure interests as measured with the Leisure Interest Questionnaire (J. C. Hansen, 1998). Only partial convergence was found for the structure of leisure interests with J. L. Holland's (1985) model of vocational interest structure, suggesting that researchers should be cautious about using vocational interests as markers for leisure interests. However, the similarity in structure of interests across the three samples was greater than hypothesized. Implications for research on leisure interests and for counseling practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lake trout in northern Lake Huron spawn on submerged drumlins

Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.     

Zür Qualitäserhaltung dünnschaliger Kartoffeln durch Rütgenstrahlen niederer Dosis

European Food Research and Technology - Dünsschalige Kartoffeln der Sorten ?Bona” und ?Heida” wurden unmittelbar nach der Rodung in einer besonderen...