MONEY ILLUSION, GORMAN AND LAU

Any demand equation satisfying Lau’s (1982) Fundamental Theorem of Exact Aggregation and 0° homogeneity in prices and income will have a Gorman (1981) functional form for each income term. This property does not depend on symmetry or adding up. The implications of this result are illustrated by an extensive example.Demand, exact aggregation, functional form, homogeneity

Lap Splicing of Large High-Strength Steel Reinforcing Bars

Use of large bars is advantageous in large structures like nuclear power plants. Nevertheless, ACI 318-19 prohibits tension lap splices for bars larger than No. 11 [36 mm] because limited test data are available. Eleven large-scale reinforced concrete beams with tension lap splices were tested under monotonically increasing four-point bending until failure to support design provisions for large diameter bars (No. 14 and 18 [43 and 57 mm]). Specimens had different amounts of transverse reinforcement, nominal concrete compressive strengths of 5 or 10 ksi [35 or 69 MPa], and target bar stresses at splice failure of 60 and 100 ksi [420 to 690 MPa] for No. 14 [43 mm] bars and 60 ksi [420 MPa] for No. 18 [57 mm] bars.Test results show that lap splices of No. 14 [43 mm] bars can develop bar stresses up to 100 ksi [690 MPa] and that lap splices of No. 18 [57 mm] bars can develop bar stresses up to at least 60 ksi [420 MPa]. These limits reflect the scope of the text matrix, as there was no indication that higher bar stresses cannot be attained. Analyses showed that both the ACI 408R-03 and ACI 318-19 equations for lap splice lengths become less conservative as bar size increases. This trend was apparent when comparisons were made using prior test results between groups of specimens with No. 6 [19 mm] and smaller bars, No. 7 to No. 10 [22 to 32 mm] bars, No. 11 [36 mm] bars, and bars larger than No. 11 [36 mm]. Two methods are proposed for modifying ACI 408R-03 and ACI 318-19 development length equations to obtain similar levels of conservatism across all bar sizes: a bar size factor (1.15 for No. 11 [36 mm] bars and 1.25 for larger bars) in the numerator of the development length equations or an increased exponent on the bar diameter term (replacing d_b with d_b^1.35 in ACI 408R-03 and d_b^1.25 in ACI 318-19). A minimum clear cover of one bar diameter is recommended for all lap splices. Transverse reinforcement should also be required throughout lap splices of No. 14 and 18 [43 and 57 mm] bars, as even small quantities (K_tr/d_b= 0.5) tended to reduce size effect. Other analyses showed that increasing the limit on ((c_b+K_tr)/d_b ) in the ACI 318-19 development length provisions from 2.5 to 3.5 results in similar conservatism for all amounts of confinement. It is also recommended that development length l_d be limited to 50db when designing unconfined lap splices

A Bayesian assessment of an approximate model for unconfined water flow in sloping layered porous media

The prediction of water table height in unconfined layered porous media is a difficult modelling problem that typically requires numerical simulation. This paper proposes an analytical model to approximate the exact solution based on a steady-state Dupuit–Forchheimer analysis. The key contribution in relation to a similar model in the literature relies in the ability of the proposed model to consider more than two layers with different thicknesses and slopes, so that the existing model becomes a special case of the proposed model herein. In addition, a model assessment methodology based on the Bayesian inverse problem is proposed to efficiently identify the values of the physical parameters for which the proposed model is accurate when compared against a reference model given by MODFLOW-NWT, the open-source finite-difference code by the U.S. Geological Survey. Based on numerical results for a representative case study, the ratio of vertical recharge rate to hydraulic conductivity emerges as a key parameter in terms of model accuracy so that, when appropriately bounded, both the proposed model and MODFLOW-NWT provide almost identical results

The use of electric fields for edible coatings and films development and production: A review

Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. A diversity of raw materials used to produce edible coatings and films are extracted from marine and agricultural sources, including animals and plants. Electric fields processing holds advantage in producing safe, wholesome and nutritious food. Recently, the presence of a moderate electric field during the preparation of edible coatings and films was shown to influence their main properties, demonstrating its usefulness to tailor edible films and coatings for specific applications. This manuscript reviews the main aspects of the use of electric fields in the production of edible films and coatings, including the effect in their transport and mechanical properties, solubility and microstructure.Fundação para a Ciência e a Tecnologia (FCT), Portugal.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brasil

The ontogeny of antipredator behavior: age differences in California ground squirrels (Otospermophilus beecheyi) at multiple stages of rattlesnake encounters

Newborn offspring of animals often exhibit fully functional innate antipredator behaviors, but they may also require learning or further development to acquire appropriate responses. Experience allows offspring to modify responses to specific threats and also leaves them vulnerable during the learning period. However, antipredator behaviors used at one stage of a predator encounter may compensate for deficiencies at another stage, a phenomenon that may reduce the overall risk of young that are vulnerable at one or more stages. Few studies have examined age differences in the effectiveness of antipredator behaviors across multiple stages of a predator encounter. In this study, we examined age differences in the antipredator behaviors of California ground squirrels (Otospermophilus beecheyi) during the detection, interaction, and attack stages of Pacific rattlesnake (Crotalus oreganus) encounters. Using free-ranging squirrels, we examined the ability to detect free-ranging rattlesnakes, snake-directed behaviors after discovery of a snake, and responses to simulated rattlesnake strikes. We found that age was the most important factor in snake detection, with adults being more likely to detect snakes than pups. We also found that adults performed more tail flagging (a predator-deterrent signal) toward snakes and were more likely to investigate a snake’s refuge when interacting with a hidden snake. In field experiments simulating snake strikes, adults exhibited faster reaction times than pups. Our results show that snake detection improves with age and that pups probably avoid rattlesnakes and minimize time spent in close proximity to them to compensate for their reduced reaction times to strikes

United States 1947

Relief shown pictorially.; Includes illustrations and text.; "Issued ... as part of 1947 commemoration honoring pioneers ... This pictographic map ... is made available through generous cooperation of the Chicago, Burlington & Quincy Railroad Company, some of whose lines parallel, cross and recross the old Mormon Trail."Colo