An economic analysis of grid-connected residential solar photovoltaic power systems

Prepared for the United States Dept. of Energy under Contract no. EX-76-A-01-2295, Task order 37.The question of the utility grid-connected residential market for photovoltaics is examined from a user-ownership perspective. The price is calculated at which the user would be economically indifferent between having a photovoltaic system and not having a system. To accomplish this, a uniform methodology is defined to determine the value to the user-owner of weather-dependent electric generation technologies. Two models are implemented for three regions of the United States, the first of which is a previously developed simulation of a photovoltaic residence. The second is an economic valuation model which is required to translate the ouputs from the simulation into breakeven array prices. Special care is taken to specify the input assumptions used in the models. The accompanying analysis includes a method for analyzing the year-to-year variation in hourly solar radiation data and a discussion of the appropriate discount rate to apply to homeowner investments in photovoltaic systems. The results of this study indicate that for the regions characterized by Boston, Omaha, and Phoenix, under the assumptions noted, photovoltaic module breakeven costs for the residential application are in the range of $.68,$.43 and $1.27 per peak system watt respectively (.42, .24, .89 per peak module watt)

Information Search on the Web: Understanding the Impact of Response Time Delays with Information Foraging Theory

Web delays are a persistent and highly publicized problem. Long delays have been shown to reduce information search, but less is known about the impact of more modest “acceptable” delays — delays that do not substantially reduce user satisfaction. Prior research suggests that as the time and effort required to complete a task increases, decision-makers tend to reduce information search at the expense of decision quality. In this study, the effects of an acceptable time delay (seven seconds) on information search behavior were examined. Results showed that increased time and effort caused by acceptable delays provoked increased information search

Identification of the proteins, including MAGEG1, that make up the human SMC5-6 protein complex

The SMC protein complexes play important roles in chromosome dynamics. The function of the SMC5-6 complex remains unclear, though it is involved in resolution of different DNA structures by recombination. We have now identified and characterized the four non-SMC components of the human complex and in particular demonstrated that the MAGEG1 protein is part of this complex. MAGE proteins play important but as yet undefined roles in carcinogenesis, apoptosis, and brain development. We show that, with the exception of the SUMO ligase hMMS21/hNSE2, depletion of any of the components results in degradation of all the other components. Depletion also confers sensitivity to methyl methanesulfonate. Several of the components are modified by sumoylation and ubiquitination

Nse2, a component of the Smc5-6 complex, is a SUMO ligase required for the response to DNA damage

The Schizosaccharomyces pombe SMC proteins Rad18 (Smc6) and Spr18 (Smc5) exist in a high-M(r) complex which also contains the non-SMC proteins Nse1, Nse2, Nse3, and Rad62. The Smc5-6 complex, which is essential for viability, is required for several aspects of DNA metabolism, including recombinational repair and maintenance of the DNA damage checkpoint. We have characterized Nse2 and show here that it is a SUMO ligase. Smc6 (Rad18) and Nse3, but not Smc5 (Spr18) or Nse1, are sumoylated in vitro in an Nse2-dependent manner, and Nse2 is itself autosumoylated, predominantly on the C-terminal part of the protein. Mutations of C195 and H197 in the Nse2 RING-finger-like motif abolish Nse2-dependent sumoylation. nse2.SA mutant cells, in which nse2.C195S-H197A is integrated as the sole copy of nse2, are viable, whereas the deletion of nse2 is lethal. Smc6 (Rad18) is sumoylated in vivo: the sumoylation level is increased upon exposure to DNA damage and is drastically reduced in the nse2.SA strain. Since nse2.SA cells are sensitive to DNA-damaging agents and to exposure to hydroxyurea, this implicates the Nse2-dependent sumoylation activity in DNA damage responses but not in the essential function of the Smc5-6 complex

Heart Rate and Rating of Perceived Exertion During High-Intensity Interval Training: Implications for Prescribing Intensity

High-intensity interval training (HIIT) is a popular and effective time-efficient alternative to moderate-intensity continuous training for improving cardiorespiratory fitness. However, there is limited research investigating the most effective and practical way to prescribe training intensities for HIIT. PURPOSE: To determine heart rate (HR) and rating of perceived exertion (RPE) responses across a bout of HIIT. Additionally, the relationship between HR and RPE was examined. METHODS: Young adults (n=16; age 21.8±1.4 years; 10 females) visited the lab on two separate occasions. At the first visit, participants completed an incremental exercise test on a cycle ergometer to determine peak power output (PPO). During the second lab visit participants completed the HIIT protocol which involved ten, 1-minute bouts of cycling at 80% PPO interspersed with 1-minute of active rest cycling at 20% PPO. HR and RPE were measured at the end of the first, fifth, and tenth work intervals using the CR10 Borg scale. Differences in HR and RPE across the training session were determined using one-way repeated measures ANOVAs. Pearson correlations were utilized to assess relationships. RESULTS: HR and RPE both significantly increased from the first (HR 157±16 bpm; RPE 5.0±1.8) to the fifth interval (HR 174±14 bpm; RPE 6.8±1.7; p0.05 for both). There were no significant relationships between HR and RPE for any of the time points (r=-0.01 to -0.34, p=0.19 to 0.89) or the average of the session (r=0.37, p=0.16). CONCLUSIONS: HR and RPE both increased initially during the HIIT session with no further increase after mid-point. There were no significant relationships between HR and RPE. These findings suggest that RPE, using the CR10 Borg scale, may not replicate HR for determining intensity during HIIT. Future research may be beneficial to determine a practical method for prescribing exercise intensity during HIIT

The Buck Stops There: The Impact of Perceived Accountability and Control on the Intention to Delegate to Software Agents

Software agents with the ability to recommend actions, aid decision-making, and actually make decisions are becoming increasingly common. In many situations, users now choose whether or not to delegate tasks to these agents. While some research has examined software agents, relatively little is known about the factors that influence the intention to delegate decisions to them. An experiment was used to examine the influence of perceived accountability, extent of control, and trust in the agent on the intention to delegate a travel arrangement decision. Users were more likely to delegate to agents that gave them greater control by requiring them to approve the agent’s recommendation before the decision was completed than to agents that performed the task autonomously without intervention after it was delegated. Contrary to expectations, intention to delegate increased as perceived accountability increased. Participants may perceive delegation as a means to shift blame from themselves to the agent and thus mitigate risk resulting from potential negative decision outcomes

Situation Normality and the Shape of Search: The Effects of Time Delays and Information Presentation on Search Behavior

Delays have become one of the most often cited complaints of web users. Long delays often cause users to abandon their searches, but how do tolerable delays affect information search behavior? Intuitively, we would expect that tolerable delays should induce decreased information search. We conducted two experiments and found that as delay increased, a point occurs at which time within-page information search increases; that is, search behavior remained the same until a tipping point occurs where delay increases the depth of search. We argue that situation normality explains this phenomenon; users have become accustomed to tolerable delays up to a point (our research suggests between 7 and 11 s), after which search behavior changes. That is, some delay is expected, but as delay becomes noticeable but not long enough to cause the abandonment of search, an increase occurs in the “stickiness” of webpages such that users examine more information on each page before moving to new pages. The net impact of tolerable delays was counterintuitive: tolerable delays had no impact on the total amount of data searched in the first experiment, but induced users to examine more data points in the second experiment