To assess the potential of price and alternative demand side management (DSM) policies as an urban water resource management tool, an econometric model of residential demand is formulated and estimated. This econometric model incorporates alternative DSM policy instruments (such as water allocations, use restrictions, public education) and increasing block pricing schedules. The analysis relies on cross-sectional monthly time-series data for eight water agencies in California representing 24% of the state's population (7.1 million people). Results suggest that both price and alternative DSM policies were effective in reducing demand. However, the magnitude of the reduction in demand varied among policy instruments.

The properties of cardiac L-type channels have been well characterized electrophysiologically, and many such studies have demonstrated that the channels are regulated by a cAMP-dependent pathway. However, the subunit composition of native cardiac L-type calcium channels has not been completely defined. Furthermore, a very important question exists regarding the status of the C-terminal domain of the pore-forming ␣ 1 subunit, as this domain has the potential to be the target of protein kinases but may be truncated as a result of posttranslational processing. In the present studies, the ␣ 1C and ␤ 2 subunits were identified by subunit-specific antibodies after partial purification from heart membranes, or immunoprecipitation from cardiac myocytes. Both the ␤ 2 and the full-length ␣ 1C subunits were found to be expressed and co-localized in intact cardiac myocytes along T-tubule membranes. Using a quantitative antibody binding analysis, we demonstrated that the majority of the ␣ 1C subunits in intact cardiac myocytes appear to be full-length. In addition, we observed that adenylyl cyclase is localized in a pattern similar to the channel subunits in cardiac myocytes. Taken together, our results provide new insights into the structural basis for understanding the regulation of L-type calcium channels by a cAMP-mediated signaling pathway.The regulation of ion channels by protein phosphorylation and dephosphorylation is a common theme in neurobiology. One of the most extensively studied examples involves the cAMP-mediated regulation of the voltage-activated L-type calcium channel in heart. The activation of ␤-adrenergic receptors by norepinephrine facilitates the opening of cardiac L-type channels and regulates cardiac contractility through a protein kinase A (PKA) 1 -mediated phosphorylation of the channels or related proteins (1, 2). Although many electrophysiological studies have centered on this important regulatory pathway, very little is known about the biochemical properties of the rare membrane proteins that comprise the channels and the molecular events that underlie their regulation.Important issues need to be resolved to fully understand the regulatory processes that occur in this prototypical system. An essential first step is to understand the subunit composition of cardiac calcium channels. Most voltage-activated calcium channels are multisubunit complexes composed minimally of pore-forming ␣ 1 subunits along with accessory ␤ and ␣ 2 ␦ subunits. Earlier studies have demonstrated that purified L-type calcium channels contain an ␣ 1 subunit and the universal ␣ 2 ␦ subunit (3, 4). Subsequently, cDNA cloning predicted the ␣ 1C isoform to be part of the cardiac calcium channels (5). While the ␣ 1C cDNA predicts a protein with a molecular mass of 242 kDa (5), L-type channel proteins purified from avian and mammalian heart contained ␣ 1 subunits of [190][191][192][193][194][195][196][197][198][199][200]6). Recent studies have confirmed the suspicion that the purified proteins were ␣ 1C subunits that were truncat...

This paper describes a robot system for the automatic pruning of grape vines. A mobile platform straddles the row of vines, and it images them with trinocular stereo cameras as it moves. A computer vision system builds a three-dimensional (3D) model of the vines, an artificial intelligence (AI) system decides which canes to prune, and a six degree-of-freedom robot arm makes the required cuts. The system is demonstrated cutting vines in the vineyard. The main contributions of this paper are the computer vision system that builds 3D vine models, and the test of the complete-integrated system. The vine models capture the structure of the plants so that the AI system can decide where to prune, and they are accurate enough that the robot arm can reach the required cuts. Vine models are reconstructed by matching features between images, triangulating feature matches to give a 3D model, then optimizing the model and the robot's trajectory jointly (incremental bundle adjustment). Trajectories are estimated online at 0.25 m/s, and they have errors below 1% when modeling a 96 m row of 59 vines. Pruning each vine requires the robot arm to cut an average of 8.4 canes. A collision-free trajectory for the arm is planned in intervals of 1.5 s/vine with a rapidly exploring random tree motion planner. The total time to prune one vine is 2 min in field trials, which is similar to human pruners, and it could be greatly reduced with a faster arm. Trials also show that the long chain of interdependent components limits reliability. A commercially feasible pruning robot should stop and prune each vine in turn. C 2016 Wiley Periodicals, Inc.

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