99 research outputs found

    Polar Exploration with Nimbus Meteorological Satellite

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    Discusses the use of photographs from spacecraft to determine various kinds of features, based on experiences with Nimbus I during Aug-Sept 1964. Advanced Vidicon Camera System photographs of sea and glacier ice in Canada, Greenland, and the Antarctic are shown; and the nature and quality of data yielded are considered. The striking pattern of sunlight and shadows resulting from low sun angle near the poles is noted, also a method for estimating heights of peaks, glacier slopes, etc from length of the shadows. Surface temperatures and snow and ice emissivities in the Antarctic were determined from High Resolution Infra-Red photographs

    Variety of Methodological Approach in Economics

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    It has been argued by some that the distinction between orthodox economics and heterodox economics does not fit the growing variety in economic theory, unified by a common methodological approach. On the other hand, it remains a central characteristic of heterodox economics that it does not share this methodological approach, but rather represents a range of alternative methodological approaches. The paper explores the evidence, and arguments, for variety in economics at different levels, and a range of issues which arise. This requires in turn a discussion of the meaning of variety in economics at the different levels of reality, methodology, method and theory. It is concluded that there is scope for more, rather than less, variety in economic methodologies, as well as within methodologies. Further, if variety is not to take the form of “anything goes”, then critical discussion by economists of different approaches to economics, and of variety itself, is required

    Morphology and foliar chemistry of containerized Abies fraseri (Pursh) Poir. seedlings as affected by water availability and nutrition

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    • We present the results of a two-year (2007–2008) greenhouse study investigating the effect of water availability and nitrogen fertilization on the growth, biomass partitioning, and foliar nutrient content of Abies fraseri (Pursh) Poir. • Fertilizer and moisture content (irrigation) were varied in a factorial experiment combining four levels of irrigation and three levels of fertilization to evaluate growth and foliar nutrient content. In addition, a numerical optimization was used to estimate appropriate levels of each factor necessary to achieve simulated goals for response variables. • Irrigation increased the height growth by 12 to 35% depending on the fertilization treatment (p = 0.0001). Fertilization increased height growth by 10 to 26% (p = 0.02). A similar response was observed for stem diameter growth (SDG). Total biomass accumulation increased as result of positive response of stem and root biomass development, and foliar nitrogen content was positively affected by nitrogen fertilization and negatively affected by irrigation. The numerical optimization for simulated target growth and nitrogen content responses produced levels of input combinations with high desirability factors to achieve the target responses. • These results suggest that nutrient addition is a strong determining factor for early development of this species. The improved growth efficiency in this study is likely attributed to a combination of factors including, improved photosynthetic capacity, decreased stomatal limitations, or increased resource allocation to stems

    Above- and below-ground biomass accumulation, production, and distribution of sweetgum and loblolly pine grown with irrigation and fertilization.

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    Abstract: Increased forest productivity has been obtained by improving resource availability through water and nutrient amendments. However, more stress-tolerant species that have robust site requirements do not respond consistently to irrigation. An important factor contributing to robust site requirements may be the distribution of biomass belowground, yet available information is limited. We examined the accumulation and distribution of above- and below-ground biomass in sweetgum (Liqrridambar sfyrac$lua L.) and loblolly pine (Pinus taeda L.) stands receiving irrigation and fertilization. Mean annual aboveground production after 4 years ranged from 2.4 to 5.1 ~g.ha-'.year' for sweetgum and from 5.0 to 6.9 ~g.ha-l.year-l for pine. Sweetgum responded positively to irrigation and fertilization with an additive response to irrigation + fertilization. Pine only responded to fertilization. Sweetgum root mass fraction (RME)in creased with fertilization at 2 years and decreased with fertilization at 4 years. There were no detectable treatment differences in loblolly pine RMF. Development explained from 67% to 98% of variation in shoot versus root allometry for ephemeral and perennial tissues, fertilization explained no more than 5% of the variation in for either species, and irrigation did not explain any. We conclude that shifts in allocation from roots to shoots do not explain nutrient-induced growth stimulations

    Titan's cold case files - Outstanding questions after Cassini-Huygens

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    Abstract The entry of the Cassini-Huygens spacecraft into orbit around Saturn in July 2004 marked the start of a golden era in the exploration of Titan, Saturn's giant moon. During the Prime Mission (2004–2008), ground-breaking discoveries were made by the Cassini orbiter including the equatorial dune fields (flyby T3, 2005), northern lakes and seas (T16, 2006), and the large positive and negative ions (T16 & T18, 2006), to name a few. In 2005 the Huygens probe descended through Titan's atmosphere, taking the first close-up pictures of the surface, including large networks of dendritic channels leading to a dried-up seabed, and also obtaining detailed profiles of temperature and gas composition during the atmospheric descent. The discoveries continued through the Equinox Mission (2008–2010) and Solstice Mission (2010–2017) totaling 127 targeted flybys of Titan in all. Now at the end of the mission, we are able to look back on the high-level scientific questions from the start of the mission, and assess the progress that has been made towards answering these. At the same time, new scientific questions regarding Titan have emerged from the discoveries that have been made. In this paper we review a cross-section of important scientific questions that remain partially or completely unanswered, ranging from Titan's deep interior to the exosphere. Our intention is to help formulate the science goals for the next generation of planetary missions to Titan, and to stimulate new experimental, observational and theoretical investigations in the interim

    The Historical Perspective of the Problem of Interpersonal Comparisons of Utility

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    The starting-point of the article is the inconsistency between the established practice of acceptance in many cases, of economic policy (i.e. progressive taxation, national insurance policies) and the theoretical rejection of interpersonal comparisons of utility who see it as an unscientific value judgement. The inconsistency is explained by identifying three groups of theorists: (1) those who thought of comparability as a value judgement and unacceptable for economic policy considerations (positivists), (2) those who agreed with the positivists, on the normative nature of comparability but accepted it as a basis for economic policy, and (3) those who thought of it as part of a scientific economics. The implication was that, despite the dominance of positivist methodology in other sub-fields, the historical experience points to the difficulty of applying positivist methodology to the issue of comparability. If the inconsistency is thus due to the inappropriateness of the positivist approach, the only possible solution is the explicit abandonment of this approach at least in matters related to the collective aspects of economics
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