The Janson inequalities for general up-sets

Janson and Janson, Luczak and Rucinski proved several inequalities for the lower tail of the distribution of the number of events that hold, when all the events are up-sets (increasing events) of a special form - each event is the intersection of some subset of a single set of independent events (i.e., a principal up-set). We show that these inequalities in fact hold for arbitrary up-sets, by modifying existing proofs to use only positive correlation, avoiding the need to assume positive correlation conditioned on one of the events.Comment: 5 pages. Added weighted varian

Sesqui-type branching processes

We consider branching processes consisting of particles (individuals) of two types (type L and type S) in which only particles of type L have offspring, proving estimates for the survival probability and the (tail of) the distribution of the total number of particles. Such processes are in some sense closer to single- than to multi-type branching processes. Nonetheless, the second, barren, type complicates the analysis significantly. The results proved here (about point and survival probabilities) are a key ingredient in the analysis of bounded-size Achlioptas processes in a recent paper by the last two authors.Comment: 23 pages. References update

The future cost of electricity storage and its value in low-carbon power systems

The energy sector is transforming rapidly to reduce carbon emissions and limit global climate change. Electricity storage can provide the required flexibility to balance intermittent and relatively inflexible power generation with demand in low-carbon power systems. However, falling investment cost, the wide range of technologies with different performance characteristics and the wide range of use cases with different performance requirements lead to uncertainty on its commercial viability. To assess electricity storage against alternatives and enable further investment in low-carbon technologies, policy-makers and industry need certainty on cost reduction potentials and its value in enabling low-carbon power systems. This thesis creates an experience curve dataset for 11 electricity storage technologies, identifying investment cost reductions to US$325±125/kWh (systems) and US$155±45/kWh (packs) once 1 TWh capacity is installed for each technology. This could be achieved by 2027–2040 based on market growth projections. Expert interviews highlight the importance of production scale-up as cost reduction driver and provide a detailed list of technical and value chain innovations for two prominent storage technologies. The quantification of future application-specific lifetime cost with a novel, comprehensive formula, that accounts for all relevant cost and performance parameters, indicates that lithium ion will be the most cost competitive for most applications by 2030. Lower financing cost, in general, and performance improvements for alternative technologies specifically could challenge this dominance. Matching future lifetime cost to revenue potentials across applications reveals profitable business cases in three distinct application categories with specific requirements. An analysis of modelled flexibility capacity in power system studies reveals two approaches to assess electricity storage capacity requirements in low-carbon power systems. In both approaches, the flexibility capacity requirement relative to peak demand increases linearly with increasing wind, solar and nuclear penetration, albeit at different rates, requiring up to 65% or 115% in a fully decarbonised power system. These insights combined with the online availability of experience curve dataset and lifetime cost tool increase transparency on the future cost of electricity storage and its value in low-carbon power systems, supporting policy and industry in transforming the energy sector.Open Acces

Gender of interviewer effects in a multitopic centralized CATI panel survey

"This paper is motivated by two recent articles which show that numerous studies which analyzed gender of interviewer effects did not take interviewer nonresponse selection effects into account. For example, interviewers may be more successful at recruiting respondents with characteristics similar to themselves and who give answers that are similar to their own, and this may result in spurious gender of interviewer effects. Our research is novel because it uses data from a large panel survey in which the same respondent is asked the same questions repeatedly by interviewers of random genders using the centralized telephone mode. We use the panel design to show the importance of checking for all relevant variables in models where selection may cause bias. To this end, we use respondent fixed effects models as a reference to yield unbiased coefficients. We find gender of interviewer effects that are in line with social desirability theory on gender issues such as female discrimination. However, not all gender-related questions are affected by gender of interviewer effects and, in addition, we do not find any effects on political and (factual) household task related questions. In line with the notion of social distance, there is a higher likelihood that answers respondents are less comfortable with are given to interviewers of the same gender regarding (sensitive) health questions." (author's abstract

The proteome of the heterocyst cell wall in Anabaena sp. PCC 7120

Anabaena sp. PCC 7120 is a filamentous cyanobacterium that serves as a model to analyze prokaryotic cell differentiation, evolutionary development of plastids, and the regulation of nitrogen fixation. The cell wall is the cellular structure in contact with the surrounding medium. To understand the dynamics of the cell wall proteome during cell differentiation, the cell wall from Anabaena heterocysts was enriched and analyzed. In line with the recently proposed continuity of the outer membrane along the Anabaena filament, most of the proteins identified in the heterocyst cell-wall fraction are also present in the cell wall of vegetative cells, even though the lipid content of both membranes is different