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  • Springer  (23)
  • American Association for the Advancement of Science (AAAS)  (4)
  • 2000-2004  (3)
  • 1980-1984  (24)
  • 2002  (3)
  • 1982  (15)
  • 1980  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Radiation losses due to discontinuities in asymmetric three-layer optical waveguides (1980)
    Springer
    Optical and quantum electronics 12 (1980), S. 143-158 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract In this paper, the radiation losses caused by film thickness and refractive index discontinuities in asymmetric slab waveguides are examined theoretically. A technique developed by Mahmoud and Beal for dealing with the continuous part of the radiation spectrum is used. Several numerical examples which show the radiation loss for various waveguide configurations are presented and discussed and, where appropriate, comparisons with other related work made. In the case of asymmetric thickness steps, the radiation losses are found to be appreciably higher than those computed for symmetric guides. The radiation losses for guides having the same thickness were found to decrease as the guide thickness increased. Once the TE1 mode become guided, the losses decreased rapidly. However, if the two guides had different thickness then it was found that the losses exhibited a minimum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619558
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of diversity and pattern on relative yields of four michigan first year fallow field plant species (1980)
    Springer
    Oecologia 45 (1980), S. 366-371 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. A study was designed to investigate the effects of intra and inter-specific competition on the productivity of single and multi-species stands of plants normally dominant in first year old-field communities of mid-Michigan. The four species used were Amaranthus retroflexus, Chenopodium album, Panicum capillare and Setaria viridis. 2. Specifically, we tested (1) the relationship between diversity and productivity, (2) the effect of arrangement (pattern) of individuals within an array of old-field dominants on yield and (3) the expression of dominance and resultant allocation of yields within mixture arrays of different plant species. In direct contrast to many earlier studies, our experiments were completed in the field under natural conditions. 3. Mean yield of the highest yielding monoculture, Amaranthus, was greater than any of the yields of the mixture plots. 4. Changing the pattern within mixtures had no significant effect on the yields of the mixture plots. Distribution of biomass among the component species followed a geometric pattern similar to that predicted by the niche pre-emption hypothesis (Whittaker, 1965, 1969). Using yield as a criterion, dominance was clearly expressed in the mixture plots. Amaranthus contributed more than 50% of the yield in all of the mixture plots. 5. A relative competitive ability index (RCA) was developed to demonstrate more clearly the intra and interspecific relationships among the species in mixture plots and to “equalize” the inherent weight differential among species. Relative Competitive Ability, from highest to lowest, was Amaranthus, Chenopodium, Setaria and Panicum. 6. The paired species experiment demonstrated that the performance of species in multi-species arrays cannot be predicted from paired competition experiments. 7. In the diversity-yield experiment and the paired-species competitive ability experiment, dicotyledons were clearly superior to monocotyledons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00540207
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  • 3
    Electronic Resource
    Electronic Resource
    Carbon-13 depletion in an estuarine bivalve: Detection of marine and terrestrial food sources (1982)
    Springer
    Oecologia 55 (1982), S. 110-113 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Stable carbon isotope analysis was used to define the food sources of bivalve Chione (Austrovenus) stutchburyi in the Avon-Heathcote Estuary, Christchurch, New Zealand. δ13C values of C. stutchburyi tissue were significantly different (from -16.7‰ to -23.5‰ relative to the PDB standard) at five locations separated by less than 4 km but subject to different hydrological regimes. This is related to differences in the isotopic composition of the suspended particulate matter of the inflowing water. C. stutchburyi is shown to utilise carbon of terrestrial and marine origin depending upon its position within the estuary and local hydrology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386725
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  • 4
    Electronic Resource
    Electronic Resource
    Laser chemical physics II: Infrared multiple photon dissociation (1982)
    Springer
    Applied physics 28 (1982), S. 180-189 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 33
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697844
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  • 5
    Electronic Resource
    Electronic Resource
    The use of TA — GLC — MS as a quantitative specific EGA technique for the investigation of complex thermal decomposition reactions: The thermal decomposition of calcium propanoate (1982)
    Springer
    Journal of thermal analysis and calorimetry 25 (1982), S. 299-311 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Ein vielseitiges und flexibles System zur Analyse von gebildeten Gasen wird beschrieben, das GLC, MS (in Massen-scanning und SIM Betriebsweise) und GLC-MS umfaßt. Damit können die in zwei differentialthermoanalytischen Einheiten, einer Thermowaage oder einem direkt mit dem MS- oder GLC-Gerät gekoppelten Mikroofen aus den zu untersuchenden Substanzen entwickelten Gase analysiert werden. Einzelheiten der komputerkontrollierten Datengewinnung und Steuerung werden angegeben. Die Techniken werden zur Untersuchung der thermischen Zersetzung von Calciumpropionat herangezogen. Mechanismen werden vorgeschlagen, die die beobachteten Zersetzungsprodukte und die Festkörperreaktion erklären. Beweise werden dafür erbracht, daß bei letzterer eine Keimbildung und darauffolgendes zweidimensionales Wachstum vor sich geht, wobei die Aktivierungsenergie 315 kJ·mol−1 und der präexponentielle Faktor 4.8·1021·s−1 beträgt.
    Abstract: Резюме Описана многосторон яя и гибкая система анализа выделяющего ся газа на основе использования газо-ж идкостной хроматогр афии (ГЖХ), масс-спектрометрии (MC) и совмещенного метода ГЖХ и MC. Термовес ы или микропечь соеди нены прямо с массспектрометром или газо-жидкостным х роматографом, что поз воляет анализировать газы, выделяющиеся из веще ств в этих двух различ ных термических аналити ческих блоках. Приведены детали сбо ра и обработки данных с помощью ЭВМ. Метод был использ ован для изучения термиче ского разложения про пионата кальция. Предложен ме ханизм реакций образования продукт ов разложения и тверд отельных процессов. Предсравл ены доказательства в пользу того, что твер дотельные процессы п роисходят через стадию образов ания центров кристаллиза ции, за которой следуе т двухразмерный рост с энергией активации 315 кдж.моль−1 и предэкшо ненциальным факторо м 4,8·1021 сек−1.
    Notes: Abstract A versatile and flexible system is described for evolved gas analysis using a GLC, MS (mass scan and SIM modes) and GLC-MS. Gases evolved from materials in two differential thermal analysis units, a thermobalance or a micro-furnace linked directly to the MS or GLC can be analysed. Details are given of computer controlled data acquisition and processing. The techniques are applied to the thermal decomposition of calcium propanoate. Mechanisms are suggested to account for the observed decomposition products and the solid state process. Evidence is presented to support the view that the latter occurs via nucleation followed by two-dimensional growth with an activation energy of 315 kJ mol−1 and a pre-exponential factor of 4.8×1021s−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912955
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  • 6
    Electronic Resource
    Electronic Resource
    Description of understory development in a tree plantation with a new method of data structuring (1980)
    Springer
    Plant ecology 40 (1980), S. 185-191 
    Details
    ISSN: 1573-5052
    Keywords: Clustering ; Data-processing ; Michigan ; Numerical method ; Phytosociology ; Stratum ; Understory ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary During May and June, 1974, relevés were obtained from 30 plantation stands in the Saginaw Forest in southeastern Michigan. The canopy trees in these plantations were planted between 1904 and 1938. The understory has developed naturally over the years. The forest plantations offer opportunities for study of the effects of the canopy on the structure and species composition of the understory. A new numerical method of data structuring was used, which is based on the detection patterns of associated species within the table of 30 relevés from Saginaw Forest plantations. The method employs two difference measures. DIF 1 uses presence/absence data and DIF 2 the cover/abundance values obtained from the relevés. Both difference measures supply distance values for every pair of relevés. The least dissimilar relevés are then grouped together by the farthest neighbor agglomerative algorithm of Lance & Williams (1967). The DIF 1 analysis was inconclusive, but the DIF 2 analysis gave coherent results. It has shown that relevés with similar canopies have similar understories. The differences in understories among the relevés are due less to species composition than to the relative abundances of the species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228485
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  • 7
    Electronic Resource
    Electronic Resource
    A method for constructing binary search trees by making insertions at the root (1980)
    Springer
    International journal of parallel programming 9 (1980), S. 15-29 
    Details
    ISSN: 1573-7640
    Keywords: Binary search trees ; sorting ; symbol tables
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract It is possible to construct a binary search tree by inserting items at the root instead of adding them as leaves. When used for sorting, the method has several desirable properties, including (a) fewer comparisons in the best case, (b) fewer comparisons in the worst case, (c) a reduced variance, and (d) good performance when the items are already nearly sorted or nearly reverse sorted. For applications in which the tree is searched for existing items as well as having new items added to it (e.g., in the construction of a symbol table), the tree can be made to exhibit stacklike behavior, so that the fewest comparisons are required to locate the most recently used items.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00995807
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  • 8
    Electronic Resource
    Electronic Resource
    Work in college and subsequent wage rates (1982)
    Springer
    Research in higher education 17 (1982), S. 165-178 
    Details
    ISSN: 1573-188X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract This is an empirical study of early postenrollment wage determinants of white young men in the 1966 to 1971 period. Data are from the National Longitudinal Survey for young men. The focus is on student labor force status as a determinant of postenrollment wage rates. As such, the results are related to the combined employment and college enrollment goal expressed repeatedly in federal work-study programs from the 1930s to date. Results suggest that work while enrolled may not only support the student, but mitigate transition problems to full-time work after enrollment. The major result, found with OLS multiple regression techniques, is that student job holding significantly and positively increased postenrollment wage rates relative to youth who neither worked nor looked for work as students. This indirect effect implies that the social cost of the college work-study program may be less than the federal outlays if the extra work experience enables a youth to obtain a more productive and higher paying job after enrollment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973717
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  • 9
    Electronic Resource
    Electronic Resource
    The impact of financial aid on women's demand for higher education (1982)
    Springer
    Research in higher education 17 (1982), S. 345-361 
    Details
    ISSN: 1573-188X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract The Educational Amendments of 1972 marked a new direction in public policy regarding the scope and purpose of financial aid to higher education. Aid became more “student-oriented,” and equality of opportunity for higher education became a goal. This empirical study with national longitudinal data has made a start in policy evaluation of the effect of the 1972 Educational Amendments on the higher education acquired by young women. The most important result of financial aid receipt for young women is that those who received aid averaged 0.64 more years completed of higher education and averaged .145 greater graduation probability than similar women who did not receive aid. These results were obtained in multiple regression models in which the effects of marital status, parental background, geographic locations and economic characteristics, and tuition level were controlled for. These results suggest that policy attempts to stimulate the higher education acquired by enrolled young women by increasing the availability of financial aid are well founded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00977902
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  • 10
    Electronic Resource
    Electronic Resource
    Book reviews (1982)
    Springer
    Higher education 11 (1982), S. 237-247 
    Details
    ISSN: 1573-174X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Nature of Science, Research, Systems of Higher Education, Museum Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00139691
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