719 research outputs found

    Origins and Early Development of the Nonlinear Endogenous Mathematical Theory of the Business Cycle: Part I - The Setting

    Get PDF
    We study the emergence of the nonlinear, endogenous, theory of the business cycle, in mathematical modes, within the framework of a macroeconomic theory, which was itself going through its own formal 'birth pangs' at the same time, in the same years. The first part of the story begins in 1928 and ends, with the publication of Yasui's classic on Kaldor, Hicks and Goodwin, in 1953, and Hudson's classic of 1957. But there were other classics in the 1930s, even within some theories of the business cycles of the time - particularly the Austrian and that which may now be called the 'time-to-build' tradition, which originates in Marx and Aftalion, independently, and reaches its nonlinear formalization origins in Tinbergenís work of 1931, followed by Kalecki's theories of the business cycle, substantially influenced also by Tinbergen's classic for mathematical method. There is also what may, for want of a better name, be called the 'cobweb' tradition, on the one hand, and the tradition of Swedish Sequence Analysis, on the other (especially in the 1937 classic work of Lundberg, summarising the Swedish discussion on business cycle theory). The former having its origins, partly, in Austrian inspired search for an integration of dynamic method with equilibrium economic theory (especially represented by a series of classics by Rosenstein-Rodan, from about 1929); and partly in the well known phenomenon of lagged responses in the supply-demand interactions in agricultural and commodity markets, particularly elegantly formalised by Leontief in 1934. From the point of view of economic theory, they were all part of the emerging consensus on the need to incorporate money and áuctuations in nontrivial ways as intrinsic components of orthodox equilibrium economic theory which was characterised as static theory. The implication was that the search was for a synthesis of dynamic method with traditional static equilibrium economic theory. The origins of macroeconomic theory, generally attributed to the post-depression development of monetary theory, business cycle theory and the theory of policy, could be traced to this particular search for a synthesis and was brilliantly summarised by Kuznets in a series of pioneering contributions in 1929/30. The story we try to tell is of mathematical business cycle theory in its non-linear modes, and how it emerged from one strand of macroeconomic theory, which, as just mentioned, was itself being forged, ab initio, dynamically

    Organochlorine Pesticide Concentrations in Various Species of Migratory Passerines in Louisiana

    Get PDF
    Twenty-four specimens of southbound migratory passerines comprising 13 species were collected in northeastern Louisiana during 1986, and were subjected to gas-chromatography analyses for organochlorine pesticide compounds. Eleven of the specimens analyzed (46%) were positive for pesticides. The compounds detected were in trace amounts ranging from 1.37 to 200.14 ppb. The data indicated a further decline in pesticide burdens in birds since the ban on DDT. It also supported the hypothesis that a post-mortem breakdown of DDT to DDE may occur in avian tissues. Itis hypothesized that northbound migrants may have higher pesticide burdens than fall migrants considering the continued usage of pesticides in their wintering grounds south of the United States border

    DIGITAL IMAGE CORRELATION APPLICATION IN TENSILE TEST FOR ALUMINIUM ACCORDING TO ASTM E-8 STANDARD

    Get PDF
    Digital image correlation method is a non-contact method for strain measurement. This project was aimed to investigate the use of simple tools to obtain strain values. The objective was to evaluate the suitability of strain measurement method by processing images captured using a digital camera

    Western Kingbird (Tyrannus verticalis): Recently Established Breeding Bird in Arkansas

    Get PDF
    The Western Kingbird (Tyrannus verticalis) has nested for six consecutive years in Arkansas since 1998. Eleven nests of this species were observed in the summer of 2003 in urban areas of Fort Smith (Sebastian Co.) and Van Buren (Crawford Co.). All nests were on human-made structures. Of the 11, seven (64%) were located on power stations and the remaining four (36%) were on light posts. Mean nest height was 7.92 m (n = 11nests) and the mean width of nest poles was 31.18 cm (n= 4). Nest building lasted 12 to 13 days (mean = 12.5 days, n = 2 nests). The attentive period of female parents (time spent on nest at a stretch during incubation) and their inattentive period were highly variable and averaged 11.97 minutes and 4.08 minutes respectively. The male stayed in close proximity of the nest throughout the nest building and incubation phases. Incubation period was estimated to be 17 days (n = 2 nests). Nesting success (percentage of nests that fledged young) was 72.7% (n = 11 nests). The average number of young fledged per successful nest was 3.37 (n =8) and the average number fledged over all nests was 2.45 (n = 11). In all nests, only the female participated in nest-building and incubation. Fledging occurred 13 to 14 days after hatching (mean =13.5 days, n = 2 nests)

    Yellow-rumped Warblers (Setophaga coronata) Sipping Sap from Sapsucker Wells

    Get PDF
    The Yellow-rumped Warbler (Setophaga coronata) is one of the most ecologically generalized of the warblers. It feeds primarily on invertebrates, but often switches to fruit during winter, utilizing a wide array of foraging maneuvers. It also uses a variety of foraging substrates. Reports of these warblers taking sap from sapsucker wells are rare. Here we report 3 instances of sapsucking Yellow-rumped Warblers from Arkansas. All three observations were immediately preceded by extreme cold weather with snow or ice precipitation. We hypothesize that opportunistic sapsucking from sapsucker holes may be another strategy employed by the species to meet its nutritional requirements during harsh winters, when insects are scarce
    • …
    corecore