The economic impact of climate change on Kenyan crop agriculture: A Ricardian approach   总被引：3，自引：2，他引：1  

Jane Kabubo-Mariara  Fredrick K. Karanja 《Global and Planetary Change》2007,57(3-4):319-330

This paper measures the economic impact of climate on crops in Kenya. We use cross-sectional data on climate, hydrological, soil and household level data for a sample of 816 households. We estimate a seasonal Ricardian model to assess the impact of climate on net crop revenue per acre. The results show that climate affects crop productivity. There is a non-linear relationship between temperature and revenue on one hand and between precipitation and revenue on the other. Estimated marginal impacts suggest that global warming is harmful for crop productivity. Predictions from global circulation models confirm that global warming will have a substantial impact on net crop revenue in Kenya. The results also show that the temperature component of global warming is much more important than precipitation. Findings call for monitoring of climate change and dissemination of information to farmers to encourage adaptations to climate change. Improved management and conservation of available water resources, water harvesting and recycling of wastewater could generate water for irrigation purposes especially in the arid and semi-arid areas.  相似文献   

Environmental archaeology. Theoretical and practical approaches. N. Branch,M. Canti,P. Clark and C. Turney (eds). Publisher: Hodder Arnold,London, 2005 (240 pp.) ISBN: 0‐340‐80871‐3     

Jane Sidell 《第四纪科学杂志》2007,22(7):745-746

  相似文献   

A submillimetre survey of the kinematics of the Perseus molecular cloud – I. Data     

Emily I. Curtis  John S. Richer  Jane V. Buckle 《Monthly notices of the Royal Astronomical Society》2010,401(1):455-472

We present submillimetre observations of the   J = 3 → 2  rotational transition of ¹²CO, ¹³CO and C¹⁸O across over 600 arcmin² of the Perseus molecular cloud, undertaken with the Heterodyne Array Receiver Programme (HARP), a new array spectrograph on the James Clerk Maxwell Telescope. The data encompass four regions of the cloud, containing the largest clusters of dust continuum condensations: NGC 1333, IC348, L1448 and L1455. A new procedure to remove striping artefacts from the raw HARP data is introduced. We compare the maps to those of the dust continuum emission mapped with the Submillimetre Common-User Bolometer Array (SCUBA; Hatchell et al.) and the positions of starless and protostellar cores (Hatchell et al.). No straightforward correlation is found between the masses of each region derived from the HARP CO and SCUBA data, underlining the care that must be exercised when comparing masses of the same object derived from different tracers. From the ¹³CO/C¹⁸O line ratio the relative abundance of the two species  ([¹³CO]/[C¹⁸O]∼ 7)  and their opacities (typically τ is 0.02–0.22 and 0.15–1.52 for the C¹⁸O and ¹³CO gas, respectively) are calculated. C¹⁸O is optically thin nearly everywhere, increasing in opacity towards star-forming cores but not beyond  τ₁₈∼ 0.9  . Assuming the ¹²CO gas is optically thick, we compute its excitation temperature, T _ex (around 8–30 K), which has little correlation with estimates of the dust temperature.  相似文献   

Meteoric cosmogenic Beryllium-10 adsorbed to river sediment and soil: Applications for Earth-surface dynamics     

Jane K. Willenbring  Friedhelm von Blanckenburg 《Earth》2010,98(1-2):105-122

  相似文献   

Optimal water depth management on river-fed National Wildlife Refuges in a changing climate     

Sam Nicol  Brad Griffith  Jane Austin  Christine M. Hunter 《Climatic change》2014,124(1-2):271-284

The prairie pothole region (PPR) in the north-central United States and south-central Canada constitutes the most important waterfowl breeding area in North America. Projected long-term changes in precipitation and temperature may alter the drivers of waterfowl abundance: wetland availability and emergent vegetation cover. Previous studies have focused on isolated wetland dynamics, but the implications of changing precipitation on managed, river-fed wetlands have not been addressed. Using a structured decision making (SDM) approach, we derived optimal water management actions for 20 years at four river-fed National Wildlife Refuges (NWRs) in North and South Dakota under contrasting increasing/decreasing (+/?0.4 %/year) inflow scenarios derived from empirical trends. Refuge pool depth is manipulated by control structures. Optimal management involves setting control structure heights that have the highest probability of providing a desired mix of waterfowl habitat, given refuge capacities and inflows. We found optimal seasonal control structure heights for each refuge were essentially the same under increasing and decreasing inflow trends of 0.4 %/year over the next 20 years. Results suggest managed pools in the NWRs receive large inflows relative to their capacities. Hence, water availability does not constrain management; pool bathymetry and management tactics can be greater constraints on attaining management objectives than climate-mediated inflow. We present time-dependent optimal seasonal control structure heights for each refuge, which are resilient to the non-stationary precipitation scenarios we examined. Managers can use this information to provide a desired mixture of wildlife habitats, and to re-assess management objectives in reserves where pool bathymetry prevents attaining the currently stated objectives.  相似文献   

To encourage the others     

Jane A. Michael 《Geology Today》2001,17(5):176-176

  相似文献   

Structure, function, and neural control of pectoral fins in fishes     

Westneat  M.W. Thorsen  D.H. Walker  J.A. Hale  M.E. 《Oceanic Engineering, IEEE Journal of》2004,29(3):674-683

Fin-based propulsion systems perform well for both high-speed cruising and high maneuverability in fishes, making them good models for propulsors of autonomous underwater vehicles. Labriform locomotion in fishes is actuated by oscillation of the paired pectoral fins. Here, we present recent research on fin structure, fin motion, and neural control in fishes to outline important future directions for this field and to assist engineers in attempting biomimicry of maneuverable fin-based locomotion in shallow surge zones. Three areas of structure and function are discussed in this review: 1) the anatomical structure of the fin blade, skeleton, and muscles that drive fin motion; 2) the rowing and flapping motions that fins undergo for propulsion in fishes; and 3) the neuroanatomy, neural circuitry, and electrical muscle activity that are characteristic of pectoral fins. Research on fin biomechanics, muscle physiology and neural control is important to the comparative biology of locomotion in fishes and application of fin function for aid in aquatic vehicle design. Recommendations are made regarding fin propulsor designs based on the fin shape, activation pattern, and motion. Research on neural control of fins is a key piece in the puzzle for a complete understanding of comparative fin function and may provide important principles for engineers designing control systems for fin-like propulsors.  相似文献   

The influence of climate on gravitational processes within the Jiu river valley: G.I.S. applications     

Boengiu Sandu  Avram Sorin  Vladut Alina 《Central European Journal of Geosciences》2009,1(3):303-311

The dynamics of gravitational processes (e.g. landslides) is altered due to variation in climatic parameters. We have recorded an increasing number of such events which affect human settlements. The most important aspect that has to be emphasized is the way gravitational processes change and condition land utilization. Due to these circumstances, the analysis of these processes has great importance within the middle sector of the Jiu Valley. In order to correlate the occurrence of gravitational processes with climatic data, we have been collecting data within this valley sector during the last 15 years. The aim of this study is to describe the succession and dynamics of present processes, which should act as an alarm signal for local authorities to take adequate mitigating measures. We observe an increase in the mean annual temperature and the mean amplitude (by approximately 1?C), in addition to the frequency and severity of dry years (1992, 2000), and the frequency of rain showers. We correlate these data with knowledge of the lithology, morphometry, and piezometric levels in order to identify areas with a high potential for gravitational processes using a Geographical Information System (G.I.S.). This analysis allows us to draw a map rendering each layer separately — lithology, pedology, slope, vegetation etc. We present a map that emphasizes the areas with high potential for the development of gravitational processes in the region of the Jiu valley.  相似文献   

Rapid colorimetric determination of phosphorus in geochemical survey samples     

D. Peachey  J.L. Roberts  Jane Scot-Baker 《Journal of Geochemical Exploration》1973,2(2):115-120

A colorimetric method for the determination of phosphorus in batches of geochemical survey samples is described. The powdered material is digested with a nitric-perchloric acid mixture, excess of acid is evaporated off and the residue is leached with water. Aliquots of the leachate are treated with vanadomolybdate reagent and the yellow phosphorus complex is extracted into isobutyl methyl ketone. The colour in the organic phase, which is stable for many days, is matched against a series of similarly prepared standards. Iron, other coloured ions, and titanium do not interfere. Standard deviations of ±0.02% about a mean value of 0.20% P₂ O₅ and ±0.4% about a mean of 11.6% P₂ O₅ were obtained. At least 40 powdered samples may be analysed per working day per person.  相似文献   

Late Quaternary Environments in the Central South Island of New Zealand     

Jane M. Soons 《New Zealand geographer》1979,35(1):16-23

  相似文献