BIBS: A Lecture Webcasting System

The Berkeley Internet Broadcasting System (BIBS) is a lecture webcasting system developed and operated by the Berkeley Multimedia Research Center. The system offers live remote viewing and on-demand replay of course lectures using streaming audio and video over the Internet. During the Fall 2000 semester 14 classes were webcast, including several large lower division classes, with a total enrollment of over 4,000 students. Lectures were played over 15,000 times per month during the semester. The primary use of the webcasts is to study for examinations. Students report they watch BIBS lectures because they did not understand material presented in lecture, because they wanted to review what the instructor said about selected topics, because they missed a lecture, and/or because they had difficulty understanding the speaker (e.g., non-native English speakers). Analysis of various survey data suggests that more than 50% of the students enrolled in some large classes view lectures and that as many as 75% of the lectures are played by members of the Berkeley community. Faculty attitudes vary about the virtues of lecture webcasting. Some question the use of this technology while others believe it is a valuable aid to education. Further study is required to accurately assess the pedagogical impact that lecture webcasts have on student learning

Competition Without Chaos

California heralded the New Year with a wave of rolling blackouts, spiraling wholesale electricity prices, and at least one utility bankruptcy. California, which symbolizes the electronic age and represents an eighth of the U.S. economy and its population, faces electricity supply issues not seen since the Great Depression and the collapse of the great utility holding companies. To what extent is California the bellwether for the restructured electric industry in the United States? We do not believe that the recent crisis in California is a signal that competition and deregulation have failed. Indeed, it remains our firm belief that market-oriented restructuring of the electric industry remains the best opportunity to provide consumer benefits and to develop reliable new sources of supply. After all, a major impetus for introducing competition into the generation and marketing of electricity has been the previous failures in long-term planning decisions made by public utilities and their regulators. The regulated monopoly regime simply did not provide the correct economic incentives for a company to provide electric service efficiently. To what extent can other states that have restructured their electric industries expect to see California-like dramatic sustained price increases and supply shortages resulting in rolling blackouts? The root cause of California's problems was its long-term failure to build generating plants during the most sustained economic boom in the state's history. California's most significant restructuring problem was also a local issue. The California restructuring law required utilities collecting stranded costs to retain fixed price obligations to retail customers, while preventing them from hedging their price risk in the wholesale market by entering into long-term supply contracts. The California market design flaws have been avoided in the restructuring legislation enacted by the twenty-four states and the District of Columbia that have restructured electricity markets. Among these states are Pennsylvania and Illinois, the states where Exelon conducts public utility businesses. The restructuring efforts in these other states are generally yielding results quite different from those in California and demonstrate that thoughtful, market-oriented, evolutionary restructuring can work well for all parties. This is not a reason, however, for complacency. Government agencies, utilities and all market stakeholders must work hard to make sure this answer remains valid a few years hence. This work includes establishing appropriate pricing and incentives to encourage the building of new supply and the development of demand-side management programs; establishing regional transmission organizations in order to support the expansion of and appropriate pricing for transmission; establishing appropriate rules and pricing regarding the utilities provider of last resort or default supply obligation. The default supply issue is one of the most significant challenges to the transition to competition. If the delivery companies retain primary responsibility for arranging supply and thus lock up most of the generation sources, the result is reliable service and stable rates for customers. However, new market entrants' access to supply sources will be limited and at high prices, making it difficult for them to compete. To resolve this dilemma, we propose a bifurcated approach to default service offerings and pricing. For large customers, who have the most desirable service characteristics to competitive suppliers and thus more opportunity to hedge their price risk, the utilities' only default service obligation would be unbundled energy at a market price. For mass market customers, who lack hedging ability because of limited, if any, market development, the utilities would provide a fixed price, multi-year energy supply offering. The price for both offerings must include a risk premium adequate to compensate the utility for the risk it assumes and to avoid rates that are too low to allow alternative suppliers to compete. We believe our default supply resolution will achieve the competing goals of price stability, reliability, and the development of a mature competitive market. The California experience is not an accident or the product of bad luck. It is the product of choices, long-term choices about siting generation and transmission, and the more recent choice of a market design that imposed asymmetric risks on utilities to the ultimate detriment of all. If other states make similar choices, similar consequences can be expected to follow. In short, the California experience is no reason to reject restructuring; it is rather a forceful lesson on the importance of doing it right.

Modelling Provenance of Sensor Data for Food Safety Compliance Checking

The research described here was funded by an award made by the RCUK IT as a Utility Network+ (EP/K003569/1) and the UK Food Standards Agency. We thank the owner and staff of Rye & Soda restaurant, Aberdeen for their support throughout the project.Postprin

Does large-sized cities' urbanisation predominantly degrade environmental resources in China? Relationships between urbanisation and resources in Changjiang Delta Region

Outward expansion of urban lands in the developing nations is often associated with a substantial loss of environmental resources such as forests, wetlands, freshwater and cash crop fields. Yet, determining how different aspects of urbanisation – such as city population size and spread pattern of built-up lands – contribute to the cumulative loss of resources remains controversial. In this study, data sets were constructed describing changes to land cover across 65,200 grid cells at 1 km2 spatial resolution for China’s Changjiang Delta Region over the past 60 years. The results showed that the region lost 12.2% of total resource sites. The distribution of resource degradation showed a highly dispersed pattern and was not confined to a few intense areas associated with large cities. No empirical evidence was found that city population size alone accurately predicts the distribution of resource loss. Very large cities (N = 4) contributed 35% to the total loss, demonstrating impacts similar to those of much more scattered towns (N = 230). Urban expansion of large cities may lead to extensive resource loss; however, a set of non-linear mechanisms, such as the diminishing effects of per-unit area urban spread on resources and interactions between urban patterns and the size of urban spread, can also play a significant role in downsizing the negative effects of large cities on resource sites. Thus, effective urban policies should carefully weigh the cumulative urban spread mechanisms of both large and small cities responsible for spatially dispersed degradation of environmental resources

Double beta decay and the proton-neutron residual interaction

The validity of the pn-QRPA and -RQRPA descriptions of double beta decay transition amplitudes is analyzed by using an exactly solvable model. It is shown that the collapse of the QRPA is physically meaningful and that it is associated with the appearance of a state with zero energy in the spectrum. It is shown that in the RQRPA this particular feature is not present and that this approach leads to finite but otherwise spurious results for the double beta decay transition amplitudes near the point of collapse.Comment: LaTeX, 10 pages plus 3 fugures as LaTeX files. Accepted for publication in Physics Letters

The pattern of foreign property investment in Vietnam: the apartment market in Ho Chi Minh City

As globalization proceeds, transnational property development is increasing. Especially in emerging markets, foreign developers’ influence in changing the local landscape is becoming significant. In this research, the behavioral patterns of foreign developers in the apartment market of Ho Chi Minh City, Vietnam were identified. To understand the dynamics of foreign developers, the types of products that were being created, where the investments were located, and the differences in development strategies adopted by foreign developers in comparison to domestic counterparts were identified. To accomplish this, data on apartment projects and statistics were collected, and a series of spatial analyses including sieve mapping, histogram analysis, factor analysis and logistic regression was conducted. In addition, closer examination was made of specific cases to understand the dynamics among foreign and domestic developers, also allowing the identification of some regularities in the patterns of foreign developments. Besides presenting detailed results, this paper also seeks to account for the conditions that appear to have generated these patterns and characteristics

Virulence of malaria is associated with differential expression of Plasmodium falciparum var gene subgroups in a case-control study

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a major pathogenicity factor in falciparum malaria that mediates cytoadherence. PfEMP1 is encoded by approximately 60 var genes per haploid genome. Most var genes are grouped into 3 subgroups: A, B, and C. Evidence is emerging that the specific expression of these subgroups has clinical significance. Using field samples from children from Papua New Guinea with severe, mild, and asymptomatic malaria, we compared proportions of transcripts of var groups, as determined by quantitative polymerase chain reaction. We found a significantly higher proportion of var group B transcripts in children with clinical malaria (mild and severe), whereas a large proportion of var group C transcripts was found in asymptomatic children. These data from naturally infected children clearly show that major differences exist in var gene expression between parasites causing clinical disease and those causing asymptomatic infections. Furthermore, parasites forming rosettes showed a significant up-regulation of var group A transcripts

Use of ocean and estuarine habitats by young-of-year bluefish (Pomatomus saltatrix) in the New York Bight

Young-of-year (YOY) blue-fish (Pomatomus saltatrix) along the U.S. east coast are often assumed to use estuaries almost exclusively during the summer. Here we present data from 1995 to 1998 indicating that YOY (30–260 mm FL) also use ocean habitats along the coast of New Jersey. An analysis of historical and recent data on northern and southern ocean beaches (0.1–2 m) and the inner continental shelf (5–27 m) during extensive sampling in New Jersey waters from 1995 to 1998 indicated that multiple cohorts occurred (June–August) in every year. When comparable collections of YOY were made in the ocean and in an adjacent estuary, the abundance was 1–2 orders of magnitude greater on ocean beaches during the summer. The YOY were even more abundant in ocean habitats in the fall (September–October), presumably as a result of YOY leaving estuaries to join the coastal migration south. During 1999 and 2000, YOY bluefish were tagged with internal sequential coded wire microtags in order to refine our under-standing of habitat use and movement. Few (0.04%) of the fish tagged on ocean beaches were recaptured; however, 2.2% of the fish tagged in the estuary were recaptured from 2 to 27 days after tagging. Recaptured fish grew quickly (average 1.37 mm FL/d). On ocean beaches YOY fed on a variety of invertebrates and fishes but their diet changed with size. By approximately 80–100 mm FL, they were piscivorous and fed primarily on engraulids, a pattern similar to that reported in estuaries. Based on distribution, abundance, and feeding, both spring- and summer-spawned cohorts of YOY bluefish commonly use ocean habitats. Therefore, attempts to determine factors affecting recruitment success based solely on estuarine sampling may be inadequate and further examination, especially of the contribution of the summer-spawned cohort in ocean habitats, appears warranted