805 research outputs found
Researches into the Divine Institutes of Lactantius.
Available from British Library Document Supply Centre- DSC:D37826/81 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
EMERGING AGRICULTURAL WATER CONSERVATION PRICE INCENTIVES
Recent Bureau of Reclamation policies encourage or require irrigation districts to adopt price conservation incentives. Using unpublished survey results and new district-level information, we examine the rate structures and incentives of district water pricing. Our findings reveal that the majority of districts use fixed charges independent of the quantity of water delivered and that most conservation rate structures recently implemented are designed so that the first tier quantity allocation satisfies most crop water needs. Although other district management objectives may be satisfied, price incentives are diminished or nonexistent. The question of whether conservation is being achieved is tautological and depends on how each district defines conservation.Resource /Energy Economics and Policy,
IRRIGATION DISTRICT ADOPTION OF WATER CONSERVING RATE STRUCTURES
A binary choice model was used to identify the attributes that influence irrigation district adoption of conservation rate structures. Using principles of rate design and irrigation district administration as a framework, measures of irrigation district rate structure objectives and physical and economic conditions were developed. The factors investigated characterize the constraints under which districts operate, value and cost of water, quantity of water delivered and revenue risk for districts. Rate structure adoption was predicted with over 75% accuracy. Both significant and non-significant factors are key to understanding rate choice. Districts were more likely to adopt conservation rate pricing when the cost of water to farmers was greater, higher value crops were grown and in areas with warmer and longer growing seasons. These conditions may be interpreted as reflecting the presence of greater opportunity costs in allocating water between low and higher valued uses. Conservation rate pricing was less likely to be adopted by districts where the proportion of alfalfa to total acreage was higher and with higher per acre deliveries of water. Somewhat surprisingly, annual variation in water deliveries (which should increase the risk of revenue shortfalls) and size of the district (larger districts being more sophisticated) have little bearing on the type of rate structure adopted.Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,
Hematite coated, conductive Y doped ZnO nanorods for high efficiency solar water splitting
For the first time, hematite (α-Fe2O3) crystals were electrochemically deposited over vertically
aligned conductive zinc oxide nanorods (NR) to form a specially designed 3D heterostructure
with a unique triple layer structure. The structure formed with a thin layer of ZnFe2O4
sandwiched between the hematite and the ZnO, which forms a barrier to reduce the back
migration of holes. Hence, the charge separation is significantly improved. The small unequal
bandgaps of α-Fe2O3 and ZnFe2O4 help to enhance and broaden visible light absorption. The
electron transportation was further improved by yttrium doping in the ZnO (YZnO) NRs,
resulting in increased conductivity. This allowed the vertically aligned NRs to perform as
electron highways, which also behave as effective optical waveguides for improved light
trapping and absorption, since ZnO absorbs little visible light. All these benefits made the unique
structures suitable for high performance photoelectrochemical (PEC) water splitting.
Optimisation of α-Fe2O3 thickness led to a photocurrent density improvement from 0.66 to
0.95 mA cm−2 at 1.23 VRHE. This was further improved to 1.59 mA cm−2 by annealing at
550 °C for 3 h, representing a record-breaking photocurrent for α-Fe2O3/ZnO systems. Finally
IPCE confirmed the successful generation and transfer of photoelectrons under visible light
excitation in the specifically designed heterostructure photoanode, with 5% efficiency for blue
light, and 15% for violet light
EVALUATING THE EFFECTIVENESS OF CONSERVATION WATER-PRICING PROGRAMS: REPLY
Resource /Energy Economics and Policy,
EVALUATING THE EFFECTIVENESS OF CONSERVATION WATER-PRICING PROGRAMS
Charging farmers increasing block prices for irrigation deliveries is advocated as a means of encouraging agricultural water conservation in the West. We formulated a model of a hypothetical irrigated river basin to investigate the hyrdro-economic circumstances in which such pricing leads to water conservation. Our results indicate that increasing delivery prices may encourage irrigators to make adjustments with countervailing impacts on consumptive water use and conservation. Whether these countervailing impacts combine to conserve water or increase its consumptive use must be resolved empirically. An alternative resolution of this ambiguity is to assess water prices in terms of consumptive use.Resource /Energy Economics and Policy,
The private, the public and the hybrid in umbilical cord blood banking – a global perspective
No description supplie
Socioeconomic deprivation and surgical outcomes: ISOS and VISION-UK sub-study (Statistical Analysis Plan)
In this paper, we aim to determine if socioeconomic deprivation in England is associated with outcomes after surgery: mortality, in-hospital complications at 30 days, and hospital length of stay. We will also identify clinical factors associated with social deprivation and assess whether adjustment for these factors modify the effect of socioeconomic deprivation on outcomes for a range of surgical categories
Intestinal barrier dysfunction in inflammatory bowel diseases
The etiology of human inflammatory bowel diseases (IBDs) is believed to involve inappropriate host responses to the complex commensal microbial flora in the gut, although an altered commensal flora is not completely excluded. A multifunctional cellular and secreted barrier separates the microbial flora from host tissues. Altered function of this barrier remains a major largely unexplored pathway to IBD. Although there is evidence of barrier dysfunction in IBD, it remains unclear whether this is a primary contributor to disease or a consequence of mucosal inflammation. Recent evidence from animal models demonstrating that genetic defects restricted to the epithelium can initiate intestinal inflammation in the presence of normal underlying immunity has refocused attention on epithelial dysfunction in IBD. We review the components of the secreted and cellular barrier, their regulation, including interactions with underlying innate and adaptive immunity, evidence from animal models of the barrier's role in preventing intestinal inflammation, and evidence of barrier dysfunction in both Crohn's disease and ulcerative colitis. (Inflamm Bowel Dis 2008
Tunable hot-electron transfer within a single core-shell nanowire
We report the hot photoexcited electron transfer across the coaxial interface of a cylindrical core-shell nanowire. Modulation of the transfer rates, manifested as a large tunability of the voltage onset of negative differential resistance and of voltage-current phase, is achieved using three different modes. The coupling of electrostatic gating, incident photon energy, and the incident photon intensity to transfer rates is facilitated by the combined influences of geometric confinement and heterojunction shape on hot-electron transfer, and by electron-electron scattering rates that can be altered by varying the incident photon flux, with evidence of weak electron-phonon scattering. Dynamic manipulation of this transfer rate permits the
introduction and control of a continuously adjustable phase delay of up to about 130° within a single nanometer-scale device element
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