Outage Detection via Real-time Social Stream Analysis: Leveraging the Power of Online Complaints

Over the past couple of years, Netflix has significantly expanded its online streaming offerings, which now encompass multiple delivery platforms and thousands of titles available for instant view. This paper documents the design and development of an outage detection system for the online services provided by Netflix. Unlike other internal quality control measures used at Netflix, this system uses only publicly available information: the tweets, or Twitter posts, that mention the word “Netflix,” and has been developed and deployed externally, on servers independent of the Netflix infrastructure. This paper discussed the system and provides assessment of the accuracy of its real-time detection and alert mechanisms

Deagrarianisation and forest revegetation in a biodiversity hotspot on the Wild Coast, South Africa

Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa’s Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape

Nitrate is a negative signal for fructan synthesis and the fructosyltransferaseinducing trehalose inhibits nitrogen and carbon assimilation in excised barley leaves.

Fructan biosynthesis in barley has been shown to be up-regulated by sugar signalling and down-regulated by nitrogen. We have investigated the relationship between these two regulations. • Excised third-leaves of barley were fed nitrate or glutamine under two light intensities. Other leaf blades were supplied in the dark for 24 h with nitrate and trehalose in the presence of validamycin A, a trehalase inhibitor. • In the light, nitrate, but not glutamine, decreased fructan contents and sucrose:fructan 6-fructosyltransferase protein without affecting the levels of sucrose and other carbohydrates. In darkened leaves, trehalose increased and nitrate decreased the fructan contents and total sucrose:fructosyltransferase activity without altering the concentration of sucrose. The effect on fructan contents of trehalose disappeared, while that of nitrate still remained in subsequent incubations in water under light. Trehalose decreased and nitrate increased the light- and CO2-saturated rate of photosynthesis without significantly affecting the initial Rubisco activity. Trehalose feeding decreased the activation of Nitrate Reductase and amino acid levels, and blocked the positive effect of nitrate on the maximal activity of this enzyme. • The results indicate that nitrate, and not a down-stream metabolite, is a negative signal for fructan synthesis, independent from the positive sugar signalling and overriding it. Trehalose signalling inhibits nitrogen and carbon assimilation, at the same time inducing fructosyltransferase activity.This work was funded by the Spanish National Research and Development Programme – FEDER (1FD97-0468 grant) and the Junta de Castilla y León (CSI5/00F grant). S.K. was the recipient of a fellowship from the Spanish Agency for International Cooperation.Peer reviewe

Day length is a key regulator of transcriptomic responses to both CO2 and H2O2 in Arabidopsis

Growth day length, CO2 levels and H2O2 all impact plant function, but interactions between them remain unclear. Using a whole-genome transcriptomics approach, we identified gene expression patterns responding to these three factors in Arabidopsis Col-0 and the conditional catalase-deficient mutant, cat2. Plants grown for 5 weeks at high CO2 in short days (hCO2) were transferred to air in short days (SD air) or long days (LD air), and microarray data produced were subjected to three independent studies. The first two analysed genotype-independent responses. They identified 1549 genes differentially expressed after transfer from hCO2 to SD air. Almost half of these, including genes modulated by sugars or associated with redox, stress or abscisic acid (ABA) functions, as well as light signalling and clock genes, were no longer significant after transfer to air in LD. In a third study, day length-dependent H2O2-responsive genes were identified by comparing the two genotypes. Two clearly independent responses were observed in cat2 transferred to air in SD and LD. Most H2O2-responsive genes were up-regulated more strongly in SD air. Overall, the analysis shows that both CO2 and H2O2 interact with day length and photoreceptor pathways, indicating close networking between carbon status, light and redox state in environmental responses