2,859 research outputs found
The Impacts of Wildlife Conservation Policies on Rural Household Welfare in Zambia
KEY POLICY POINTS • Tourism is increasingly important in Zambia as a vehicle for economic growth, and has been identified as a key sector for poverty reduction due to its potential to generate off-farm income and employment in rural areas. Growth in arrivals and receipts in Zambia has outpaced average growth rates for developing countries. • Tourism in Zambia relies mostly on the stock of natural resources, including the protected area system which includes national parks and game management areas (GMAs). Co-management agreements between Zambia Wildlife Authority (ZAWA) and rural communities present opportunities and threats for households living in GMAs. • Households living in GMAs have lower average income than households in other rural areas. Yet we find that, for prime GMAs (those well stocked with wildlife), the GMA designation leads to higher incomes than households would otherwise be expected to achieve, based on their own characteristics and those of the areas in which they reside. • We further find that the benefits of living in a prime GMA accrue mostly to the wealthier segments of the population. • Though overall effects on households are positive, losses from crop damage by wildlife are a threat to this success: we find that such losses are statistically significant, large enough to be meaningful to households, and greatest in prime GMAswildlife conservation, rural households, zambia, Community/Rural/Urban Development, Environmental Economics and Policy, Food Security and Poverty, International Development, q57,
Contribution of Non-Timber Forest Products to Rural Household Income in Zambia
Non-timber forest products (NTFPs) play an important role in supporting rural livelihoods and food security in Zambia. NTFP-dependent households are poorer, have younger household heads with lower levels of education, and are located closer to district towns than other rural households are. NTFPs are a particularly important source of income in Luapula, Northwestern and Western provinces. • Income from woodfuel represented the greatest share of income for households that participated in NTFPs, and it was the most commonly reported business activity, with 68% of NTFP households reporting income from charcoal and firewood. NTFPs contribute an average of 32% to total household income among participants, with the poorest being more dependent on these sources. • Given the widespread demand for woodfuel and other forest products, it is likely that rural households will continue to engage in the extraction and trade of NTFPs as a business activity. However, charcoal production, if left unchecked, could compromise the integrity of forests and adversely affect the availability of other NTFPs. In order to reduce households’ reliance on charcoal/firewood as an income source, outreach efforts could promote other NTFPs such as wild honey, ants, and mushrooms as business activities. Mushrooms, ants, and caterpillars may particularly be important activities for female-headed households, as more female-headed households derived income from these sources.NON-TIMBER FOREST, ZAMBIA, Agricultural and Food Policy, Consumer/Household Economics,
Using the Two-Burn Escape Maneuver for Fast Transfers in the Solar System and Beyond
The two-burn maneuver to escape the gravitational pull of a central body is described. The maneuver, originally suggested by Hermann Oberth, improves efficiency considerably for a wide range of missions of interest in space exploration and scientific investigation. A clear delineation of when the maneuver is more effective is given, as are methods to extract the most advantage when using the maneuver. Some examples are given of how this maneuver can enable exploration of the outer solar system, near interstellar space, and crewed missions to Mars and beyond. The maneuver has the potential to halve the required infrastructure associated with a crewed mission to Mars and achieve increased solar escape velocities with existing spacecraft technologies
Communications Challenges In A Smaller World
Technological change and overlapping social, environmental. educational and political issues have increased the need for understandable communications among the different countries of the world. Because EngliSh is wldely used. many Americans have no other language capability and are at a disadvantage in many situations. In addition, changes in the ethnic composition of the United States have intensified the need for skills in other languages. The need for second-language skills is perhaps greater among agriculturalists than it is for other areas. The Cooperative Extension System has Important roles to play in expanding these communication skills
Communications Challenges In A Smaller World
Technological change and overlapping social, environmental. educational and political issues have increased the need for understandable communications among the different countries of the world. Because English is wldely used. many Americans have no other language capability and are at a disadvantage in many situations. In addition, changes in the ethnic composition of the United States have intensified the need for skills in other languages. The need for second-language skills is perhaps greater among agriculturalists than it is for other areas. The Cooperative Extension System has Important roles to play in expanding these communication skills
Estimating demand for perennial pigeon pea in Malawi using choice experiments
AbstractPerennial crops have numerous ecological and agronomic advantages over their annual counterparts. We estimate discrete choice models to evaluate farmers' preferences for perennial attributes of pigeon pea intercropped with maize in central and southern Malawi. Pigeon pea is a nitrogen-fixing leguminous crop, which has the potential to ameliorate soil fertility problems related to continuous maize cultivation, which are common in Southern Africa. Adoption of annual pigeon pea is relatively low but perennial production of pigeon pea may be more appealing to farmers due to some of the ancillary benefits associated with perenniality. We model perennial production of pigeon pea as a function of the attributes that differ between annual and perennial production: lower labor and seed requirements resulting from a single planting with multiple harvests, enhanced soil fertility and higher levels of biomass production. The primary tradeoff associated with perennial pigeon pea intercropped with maize is competition with maize in subsequent years of production. While maize yield is approximately twice as valuable to farmers as pigeon pea yield, we find positive yet heterogeneous demand for perenniality driven by soil fertility improvements and pigeon pea grain yield
A study on the preparation of alkyne functional nanoparticles via RAFT emulsion polymerisation
The multivalent presentation of functional groups on nanoparticle surfaces has long been exploited to attach biologically active moieties. The conventional chemistries typically used (amide, ester, disulfide) however, are non-selective and inefficient. The Huisgen azide alkyne [1,4] cycloaddition (CuAAC) ‘click’ reaction has paved the way for atom economic, and orthogonal conjugation chemistries, and is now widely used in nanoparticle science. In this work, alkyne functionalised nanoparticles were prepared, without lengthy post-nanoparticle synthesis modification procedures, exploiting RAFT emulsion polymerisations stabilised by functional macro-RAFT agents. Our results indicated that ester derived RAFT agents and addition of pendant charged groups are vital to retain colloidal stability and narrow molecular weight distributions. Finally the nanoparticles and model polymers were functionalised with an azido functional polymer and fluorescent dye, showing the surfaces were easily accessible for rapid and efficient post-polymerisation functionalisation
Redefining Gonadotropin-Releasing Hormone (GnRH) Cell Groups in the Male Syrian Hamster: Testosterone Regulates GnRH mRNA in the Tenia Tecta
Gonadotropin-releasing hormone (GnRH) regulates the production of testosterone via the hypothalamic-pituitary-gonadal axis and testosterone, in turn, regulates the GnRH system via negative feedback. We compared testosterone regulation of GnRH mRNA expression in four anatomically defined GnRH cell groups in juvenile and adult male Syrian hamsters, including a rostral population of GnRH cells in the tenia tecta. In situ hybridization histochemistry (ISHH) was used to measure GnRH mRNA in brains from castrated juveniles and adults treated with 0 mg or 2.5 mg testosterone pellets for one week. ISHH was performed on coronal sections using a 35 S-cRNA probe generated from Syrian hamster GnRH cDNA. Testosterone treatment resulted in a significant reduction in mean area of GnRH neurones covered by silver grains within the tenia tecta, but only a trend toward decreased GnRH mRNA in the diagonal band of Broca/organum vasculosum of the lamina terminalis (DBB/OVLT), medial septum (MS), and caudal preoptic area (cPOA). The effects of testosterone were independent of age. Frequency distribution analyses unveiled a significant reduction in the number of heavily labelled cells following testosterone treatment within the tenia tecta and MS. Simple regression analyses revealed a significant positive correlation between plasma luteinizing hormone concentrations and GnRH mRNA only in the tenia tecta. These data indicate that, overall, GnRH mRNA is modestly reduced by testosterone, and the most robust attenuation of GnRH mRNA occurs within the tenia tecta. This is the first report to link mechanisms of steroid negative feedback with tenia tecta GnRH neurones, providing a new focus for investigating brain region-specific steroidal regulation of GnRH synthesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75357/1/j.0007-1331.2002.00787.x.pd
Constraining the pickup ion abundance and temperature through the multifluid reconstruction of the Voyager 2 termination shock crossing
Voyager 2 observations revealed that the hot solar wind ions (the so‐called pickup ions) play a dominant role in the thermodynamics of the termination shock and the heliosheath. The number density and temperature of this hot population, however, have remained unknown, since the plasma instrument on board Voyager 2 can only detect the colder thermal ion component. Here we show that due to the multifluid nature of the plasma, the fast magnetosonic mode splits into a low‐frequency fast mode and a high‐frequency fast mode. The coupling between the two fast modes results in a quasi‐stationary nonlinear wave mode, the “oscilliton,” which creates a large‐amplitude trailing wave train downstream of the thermal ion shock. By fitting multifluid shock wave solutions to the shock structure observed by Voyager 2, we are able to constrain both the abundance and the temperature of the undetected pickup ions. In our three‐fluid model, we take into account the nonnegligible partial pressure of suprathermal energetic electrons (0.022–1.5 MeV) observed by the Low‐Energy Charged Particle Experiment instrument on board Voyager 2. The best fitting simulation suggests a pickup ion abundance of 20 ± 3%, an upstream pickup ion temperature of 13.4 ± 2 MK, and a hot electron population with an apparent temperature of ~0.83 MK. We conclude that the actual shock transition is a subcritical dispersive shock wave with low Mach number and high plasma β.Key PointsFirst multifluid MHD reconstruction of the termination shockThe termination shock is a high‐β low–Mach number dispersive shock waveObservational constraint on the pickup ion abundance and temperaturePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116003/1/jgra52059_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/116003/2/jgra52059.pd
Ultraviolet writing of channel waveguides in proton-exchanged LiNbO<sub>3</sub>
We report on a direct ultraviolet (UV) writing method for the fabrication of channel waveguides at 1.55 µm in LiNbO3 through UV irradiation of surface and buried planar waveguides made by annealed proton exchange and reverse proton exchange. A systematic study of the guidance properties as a function of the UV writing conditions is presented
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