928 research outputs found

    Sustainable agricultural development strategies in fragile lands:

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    Current trends in demography, agricultural production and rural environment in the developing countries suggest that so-called "marginal lands" must play a larger and probably growing role in food supply and economic development for the foreseeable future. To fulfill this critical role, public policy towards these lands needs to be revised. A key policy focus should be to strengthen incentives for local land users to not only maintain, but to improve the natural resource base for food and fiber supply. Such "land-improving investments" are needed to reduce production and subsistence risks and permit more intensive use without degradation. Under population and market pressure, one can expect an endogenous process of intensification, through land improvements, tenurial and institutional changes and "re-ordering" of the landscape. But this process is not automatic. Factors influencing the pace and scale of land transformation include: farmer knowledge of degradation of the degrading resource; incentives for long-term investment; capacity to mobilize resources for land investment; level of economic returns to such investment; and factors affecting the formation and function of local groups to help mobilize resources and coordinate landscape-level change. Current policies often work to constrain, rather than support, this process. New research is needed to support policy change for "marginal" lands.Land use Economic aspects., Investments.,

    Popular Culture as a Lens on Legal Professionalism

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    This Article argues that the cultural images of lawyering provide opportunities for teaching professionalism that go well beyond the teaching of ethical rules using hypothetical facts. We contend that use of different media allows teachers to chart the broad middle ground between disciplinary minima and aspirational maxima - the map of realistic professional practice. This ground includes both rule- and conduct-based ideas of professionalism: careful role definition; responsible practice management; appropriate balance between public and private commitments; and concerns over manners, dress, and work ethic. The middle ground also includes less traditional content, discussion of which brings students to appreciate the subjective disciplines of lawyering. The subjective dimension includes the feel of lawyering for the practitioner: the psychic demands of an active, fully engaged practice. It also includes the subjective experience of the clients who use lawyers, as well as the complex interweaving of subjective and external factors in the situations in which lawyers are called to act

    Fast Spectrum Material’s Testing Reactor with Variable Energy Spectra to Support Advanced Reactors Program and Light Water Reactor Sustainability Program R&D

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    The current US fleet of LWR’s are approaching the end of their original 40 year licenses. Most of these have applied for and been granted 20 year license extensions. Further increases in license length require more materials research into, amongst other things, neutron damage and stress corrosion cracking. In addition to the Light Water Reactor Sustainability program, the US maintains an Advanced Reactor program and Next Generation Nuclear Plant program. All three programs require extensive materials research, especially into fast neutron damage of core materials. A sodium cooled fast reactor based on EBR-II was designed in accordance with requirements generated by a Nuclear Energy Advisor Commission subcommittee released in November 2014. The reactor operates at 600 MWth and has sections of epithermal and thermal flux within the outer reflector. LEU metallic fuel was used without any plutonium. The active core is 1 meter tall and has an effective diameter of 1.13 meters. Magnesium Oxide was used as a reflector. The fast flux within the core depends on the enrichment of the core. Many different fuel loadings were investigated. Peak fast fluxes within the central irradiation positions vary from 5E15 to 7.5E15 n/cm^2s. Higher fluxes are associated with longer core lifetimes, which vary from greater than one year to approximately 100 days. Shuffling schemes were not analyzed, but simple refueling schemes were analyzed. The recommended driver irradiation locations provide more space at higher fluxes than comparable research reactors from around the world. The moderating region, which is composed of graphite, is highly versatile. While the size of the region was constant throughout the investigation, a wide range of configurations were studied. It is possible to irradiate materials within the reactor at fission powers and neutrons spectra typical of PWR’s and VHTR’s. Transient testing flux traps are located in the outer reflector, away from the moderating region and driver. Assemblies can be subjected to transients at constant reactor power. Both control drums and control rods can be used to control reactivity. The use of rods versus drums depends on initial keff and the degree of acceptable flux perturbation within the driver and reflector

    Financing the Small Firm Start-Up: Determinants of Debt Use

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    While academic research concerning capital structure of large corporations has been abundant in the finance literature, studies of small firms have been somewhat less common, and investigation of capital structure at origin (start-up) has been virtually nil. In this paper we present empirical evidence concerning the start-up capital structures of small firms. We base this investigation upon characteristics of both owner and firm. We find the percent of the owner\u27s income expected to be derived from the business to be positively associated with debt use and the owner\u27s age to be negatively associated with debt use. We find that more debt is obtained if the business owner is married and less if he or she is black. Similarly, more debt is prevalent among start-up firms in transportation and utilities than those in other industries. When debt obtained from other than financial institutions is considered, factors such as gender, experience, education, and expected firm size also play a role in the structure of start-up capital

    Energy conservation in dissipative processes: Teacher expectations and strategies associated with imperceptible thermal energy

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    Research has demonstrated that many students and some teachers do not consistently apply the conservation of energy principle when analyzing mechanical scenarios. In observing elementary and secondary teachers engaged in learning activities that require tracking and conserving energy, we find that challenges to energy conservation often arise in dissipative scenarios in which kinetic energy transforms into thermal energy (e.g., a ball rolls to a stop). We find that teachers expect that when they can see the motion associated with kinetic energy, they should be able to perceive the warmth associated with thermal energy. Their expectations are violated when the warmth produced is imperceptible. In these cases, teachers reject the idea that the kinetic energy transforms to thermal energy. Our observations suggest that apparent difficulties with energy conservation may have their roots in a strong and productive association between forms of energy and their perceptible indicators. We see teachers resolve these challenges by relating the original scenario to an exaggerated version in which the dissipated thermal energy is associated with perceptible warmth. Using these exaggerations, teachers infer that thermal energy is present to a lesser degree in the original scenario. They use this exaggeration strategy to productively track and conserve energy in dissipative scenarios.Comment: 19 pages, 3 figure

    Breaking new grounds in injury risk screening in soccer by deploying unsupervised learning with a special focus on sex and fatigue effects

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    In injury prevention, a vertical drop jump (DJ) is often used for screening athletes at risk for injury; however, the large variation in individual movement patterns might mask potentially relevant strategies when analysed on a group-based level. Two movement strategies are commonly discussed as predisposing athletes to ACL injuries: a deficient leg axis and increased leg stiffness during landing. This study investigated the individual movement pattern of 39 female and male competitive soccer players performing DJs at rest and after being fatigued. The joint angles were used to train a Kohonen self-organising map. Out of 19,596 input vectors, the SOM identified 700 unique postures. Visualising the movement trajectories and adding the latent parameters contact time, medial knee displacement (MKD) and knee abduction moment allow identification of zones with presumably increased injury risk and whether the individual movement patterns pass these zones. This information can be used, e.g., for individual screening and for feedback purposes. Additionally, an athlete's reaction to fatigue can be explored by comparing the rested and fatigued movement trajectories. The results highlight the ability of unsupervised learning to visualise movement patterns and to give further insight into an individual athlete's status without the necessity of a priori assumptions

    The fork protection complex recruits FACT to reorganize nucleosomes during replication

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    Chromosome replication depends on efficient removal of nucleosomes by accessory factors to ensure rapid access to genomic information. Here, we show this process requires recruitment of the nucleosome reorganization activity of the histone chaperone FACT. Using single-molecule FRET, we demonstrate that reorganization of nucleosomal DNA by FACT requires coordinated engagement by the middle and C-terminal domains of Spt16 and Pob3 but does not require the N-terminus of Spt16. Using structure-guided pulldowns, we demonstrate instead that the N-terminal region is critical for recruitment by the fork protection complex subunit Tof1. Using in vitro chromatin replication assays, we confirm the importance of these interactions for robust replication. Our findings support a mechanism in which nucleosomes are removed through the coordinated engagement of multiple FACT domains positioned at the replication fork by the fork protection complex
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