14,301 research outputs found

    How accurate is NETTO

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    The historical origin and general history of vertical current total energy variometer, including its optimum airspeed selector ring are reviewed, and some later developments of it are discussed. Polars of three sailplanes of different spans are charted for straight and circling flight, then plotted to reveal their parabolic anomaly and the effect of circling flight sink rate. These effects are further analyzed for their influence on the transient compensation of NETTO variometers as well as the speed ring. Some other disturbances due to the quality of sailplane preparation and flight dynamics are listed. Conclusions are drawn about the problems to pilots from imperfect NETTO variometer compensation and its effect on the maximization of ground speed from the speed ring. A modification for improvements to the speed ring and computer is suggested

    Effects of Securities Transaction Taxes on Depth and Bid-Ask Spread

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    This paper investigates the effects of transaction taxes on depth and bid-ask spread under asymmetric information. The paper uses a static model where a monopolistic market maker faces liquidity and informed traders. Introducing transaction taxes could, surprisingly, lead to increase in depth. Under some distributional assumptions, when market conditions are favorable to the dealer, the spread responds less than proportionally to an increase in the transaction tax while the depth actually increases. In contrast, when market conditions are unfavorable to the dealer, the spread widens more than proportionally and the depth decreases, potentially to zero, in response to an increase in the transaction tax. Our model sheds light on the disagreement in the empirical literature on the relative magnitude of transaction costs on trading volume.Asymmetric information, Securities transaction taxes, Liquidity

    Opposition and Barriers to Conservation Easements: Insights from Montana Landowners

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    A conservation easement (CE) is a voluntary agreement that perpetually limits development on private land in order to protect open space, agricultural land, and scenic amenities, as well as ecological or historic resources. Due to the fact that CEs are voluntary, an understanding of the landowner’s decision about whether or not to participate in conservation easement programs is imperative if CE use is to continue and expand. Moreover, understanding how non-participating landowners view CEs, how they regard the incentives, and how CEs fit or do not fit with their ideas regarding private property and conservation is of critical importance for conservationists in this field. This study investigated the barriers to placing conservation easements on one’s property from the perspective of landowners in western Montana. This research was conducted in an effort to better understand how these landowners view conservation easements, where opposition to easements arises from, and how these perspectives might inform efforts to conserve private lands. An additional goal of this project was to investigate how landowner views and interests relative to easements differ between different types of landowners and among different geographic areas. Finally, the hope was that knowledge gained from this study would help illuminate mechanisms for addressing these barriers. Findings indicate that there are three distinct factors that discourage western Montana landowners from CEs. The first barrier was the perpetual nature of CEs. Landowners expressed a discomfort with perpetuity and did not think that a restriction on their property could remain workable forever. The second prevalent concern was the loss of control that landowners associated with CEs. Many landowners were concerned about the excessive micro-management they believed would accompany a CE. The third barrier was a lack of trust in the organizations and agencies that work with CEs. Landowners were concerned about how conservation organizations will manage the enforcement of CE agreements and also expressed concerns regarding non-local factors and government influence. These findings indicate that there is a wide range of interrelated reasons for why landowners decide not pursue CEs. These results highlight potential avenues for addressing landowner concerns as well as areas of continued challenge to expanded CE programs

    A homological interpretation of the transverse quiver Grassmannians

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    In recent articles, the investigation of atomic bases in cluster algebras associated to affine quivers led the second-named author to introduce a variety called transverse quiver Grassmannian and the first-named and third-named authors to consider the smooth loci of quiver Grassmannians. In this paper, we prove that, for any affine quiver Q, the transverse quiver Grassmannian of an indecomposable representation M is the set of points N in the quiver Grassmannian of M such that Ext^1(N,M/N)=0. As a corollary we prove that the transverse quiver Grassmannian coincides with the smooth locus of the irreducible components of minimal dimension in the quiver Grassmannian.Comment: final version, 7 pages, corollary 1.2 has been modifie

    Transgenerational effects alleviate severe fecundity loss during ocean acidification in a ubiquitous planktonic copepod

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    Ocean acidification (OA) caused by anthropogenic CO2 emission is projected for thousands of years to come, and significant effects are predicted for many marine organisms. While significant evolutionary responses are expected during such persistent environmental change, most studies consider only short-term effects. Little is known about the transgenerational effects of parental environments or natural selection on the capacity of populations to counter detrimental OA effects. In this study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 μatm) and grown for two generations at these conditions. Our results show evidence of alleviation of OA effects as a result of transgenerational effects in P. acuspes. Second generation adults showed a 29% decrease in fecundity at 900 μatm CO2 compared to 400 μatm CO2. This was accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 μatm), fecundity would have decreased by as much as 67% compared to at 400 μatm CO2 as a result of this plasticity. However, transgenerational effects partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900 μatm CO2. This also relieved the copepods from metabolic stress, and respiration rates were lower than at 900 μatm CO2. These results highlight the importance of tests for transgenerational effects to avoid overestimation of the effects of OA

    Green Building: Sustainable Water Consultancy

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    The aim of this report is to present the results of water and wastewater modelling undertaken as part of a sustainable water consultancy for the ACF/Surrowee Green Building Project. The Institute for Sustainable Futures was engaged to develop a series of options, and to undertake modelling of the hydraulic, technical, economic and other aspects of these options and their implementation, in cooperation with the Design Team and other stakeholders. For a building of this type to achieve the goal of worldâs best practice environmental performance in a commercially viable office building, it is imperative that scheme water demand be reduced as much as possible. The practical limits of demand reduction were tested by detailed end-use modelling of various sustainable water management âoptionsâ incorporating water efficiency, reuse and dry sanitation technologies. The results of modelling and the cost benefit analysis indicate that many of the options would provide net financial gains if the potential benefits from running tours and also from sale of produce from the roofgarden were included

    Discovery of dumbbell-shaped Cs*He_n exciplexes in solid He 4

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    We have observed several new spectral features in the fluorescence of cesium atoms implanted in the hcp phase of solid helium following laser excitation to the 62^{2}P states. Based on calculations of the emission spectra using semiempirical Cs-He pair potentials the newly discovered lines can be assigned to the decay of specific Cs*Hen_{n} exciplexes: an apple-shaped Cs(AΠ3/2)(A\Pi _{3/2})He2_{2} and a dumbbell-shaped Cs(AΠ1/2)(A\Pi_{1/2}) Hen_{n} exciplex with a well defined number nn of bound helium atoms. While the former has been observed in other enviroments, it was commonly believed that exciplexes with n>2n>2 might not exist. The calculations suggest Cs(AΠ1/2)(A\Pi_{1/2}) He6_{6} to be the most probable candidate for that exciplex, in which the helium atoms are arranged on a ring around the waist of the dumbbell shaped electronic density distribution of the cesium atom.Comment: 4 pages, 4 figure

    Orbit targeting specialist function: Level C formulation requirements

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    A definition of the level C requirements for onboard maneuver targeting software is provided. Included are revisions of the level C software requirements delineated in JSC IN 78-FM-27, Proximity Operations Software; Level C Requirements, dated May 1978. The software supports the terminal phase midcourse (TPM) maneuver, braking and close-in operations as well as supporting computation of the rendezvous corrective combination maneuver (NCC), and the terminal phase initiation (TPI). Specific formulation is contained here for the orbit targeting specialist function including the processing logic, linkage, and data base definitions for all modules. The crew interface with the software is through the keyboard and the ORBIT-TGT display
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