Bayesian approach to SETI

The search for technosignatures from hypothetical galactic civilizations is going through a new phase of intense activity. For the first time, a significant fraction of the vast search space is expected to be sampled in the foreseeable future, potentially bringing informative data about the abundance of detectable extraterrestrial civilizations, or the lack thereof. Starting from the current state of ignorance about the galactic population of non-natural electromagnetic signals, we formulate a Bayesian statistical model to infer the mean number of radio signals crossing Earth, assuming either non-detection or the detection of signals in future surveys of the Galaxy. Under fairly noninformative priors, we find that not detecting signals within about $1$ kly from Earth, while suggesting the lack of galactic emitters or at best the scarcity thereof, is nonetheless still consistent with a probability exceeding $10$ \% that typically over $\sim 100$ signals could be crossing Earth, with radiated power analogous to that of the Arecibo radar, but coming from farther in the Milky Way. The existence in the Galaxy of potentially detectable Arecibo-like emitters can be reasonably ruled out only if all-sky surveys detect no such signals up to a radius of about $40$ kly, an endeavor requiring detector sensitivities thousands times higher than those of current telescopes. Conversely, finding even one Arecibo-like signal within $\sim 1000$ light years, a possibility within reach of current detectors, implies almost certainly that typically more than $\sim 100$ signals of comparable radiated power cross the Earth, yet to be discovered.Comment: Published in PNAS ahead of print October 1, 2018. Preprint has 13 pages, 7 figures + 7 pages of Supplementary Information with 5 figure

Area Coverage of Expanding E.T. Signals in the Galaxy: SETI and Drake's N

The Milky Way Galaxy contains an unknown number, $N$, of civilizations that emit electromagnetic radiation (of unknown wavelengths) over a finite lifetime, $L$. Here we are assuming that the radiation is not produced indefinitely, but within $L$ as a result of some unknown limiting event. When a civilization stops emitting, the radiation continues traveling outward at the speed of light, $c$, but is confined within a shell wall having constant thickness, $cL$. We develop a simple model of the Galaxy that includes both the birthrate and detectable lifetime of civilizations to compute the possibility of a SETI detection at the Earth. Two cases emerge for radiation shells that are (1) thinner than or (2) thicker than the size of the Galaxy, corresponding to detectable lifetimes, $L$, less than or greater than the light-travel time, $\sim 100,000$ years, across the Milky Way, respectively. For case (1), each shell wall has a thickness smaller than the size of the Galaxy and intersects the galactic plane in a donut shape (annulus) that fills only a fraction of the Galaxy's volume, inhibiting SETI detection. But the ensemble of such shell walls may still fill our Galaxy, and indeed may overlap locally, given a sufficiently high birthrate of detectable civilizations. In the second case, each radiation shell is thicker than the size of our Galaxy. Yet, the ensemble of walls may or may not yield a SETI detection depending on the civilization birthrate. We compare the number of different electromagnetic transmissions arriving at Earth to Drake's $N$, the number of currently emitting civilizations, showing that they are equal to each other for both cases (1) and (2). However, for $L < 100,000$ years, the transmissions arriving at Earth may come from distant civilizations long extinct, while civilizations still alive are sending signals yet to arrive.Comment: 10 pages, 2 figures, to be published in PAS

Preparing potential teachers for the transition from employment to teacher training: an evaluative case study of a Maths Enhancement Course

In response to a UK government drive to improve maths teaching in schools, the South West London Maths Enhancement Course (MEC) has been set up though collaboration between three Higher Education institutions (HEIs) to provide an efficient route for non maths graduates in employment to upgrade their subject knowledge and give a smooth transition into teacher training (PGCE). An evaluation of the scheme, measured against Teacher Development Agency (TDA) objectives and success criteria agreed by university staff, involved thematic analysis of focus group discussions and interviews with students and staff during both the MEC and PGCE courses. This has revealed a high level of satisfaction and success related to a number of underlying issues, particularly around student recruitment, curriculum design, peer support and staff collaboration. The model offers an example of practice transferable to a range of programmes aimed at supporting students in the transition between levels and institutions

Search for Nanosecond Near-infrared Transients around 1280 Celestial Objects

Stars and planetary system

Advertising, product quality, and complex evolving marketing systems

The paper analyses the advertising as power vs. advertising as information controversy as well as its recent empirical testing. It is stressed that this distinction focuses too much on the interaction between consumer and manufacturer while ignoring the retailer as an important stake-holder. To compensate for this lack, a complex marketing system perspective is introduced in which consumer, retailer, and manufacturer interact. However, these complex marketing systems might drift towards market equilibria which are against the consumer interests: that is, firmsmight lock out brands from the market by means of trade and sales promotions and then use advertising to protect their position. Consequently brands of better quality and/or innovative brands are barred from trade shelves

Increasing Dominance - the Role of Advertising, Pricing and Product Design

Despite the empirical relevance of advertising strategies in concentrated markets, the economics literature is largely silent on the effect of persuasive advertising strategies on pricing, market structure and increasing (or decreasing) dominance. In a simple model of persuasive advertising and pricing with differentiated goods, we analyze the interdependencies between ex-ante asymmetries in consumer appeal, advertising and prices. Products with larger initial appeal to consumers will be advertised more heavily but priced at a higher level - that is, advertising and price discounts are strategic substitutes for products with asymmetric initial appeal. We find that the escalating effect of advertising dominates the moderating effect of pricing so that post-competition market shares are more asymmetric than pre-competition differences in consumer appeal. We further find that collusive advertising (but competitive pricing) generates the same market outcomes, and that network effects lead to even more extreme market outcomes, both directly and via the effect on advertising

Universal Rights and Wrongs

This paper argues for the important role of customers as a source of competitive advantage and firm growth, an issue which has been largely neglected in the resource-based view of the firm. It conceptualizes Penrose’s (1959) notion of an ‘inside track’ and illustrates how in-depth knowledge about established customers combines with joint problem-solving activities and the rapid assimilation of new and previously unexploited skills and resources. It is suggested that the inside track represents a distinct and perhaps underestimated way of generating rents and securing long-term growth. This also implies that the sources of sustainable competitive advantage in important respects can be sought in idiosyncratic interfirm relationships rather than within the firm itself

The relation between the producer and consumer price indices: a two-country study

© 2017, Macmillan Publishers Ltd., part of Springer Nature. Marketing managers are often in a dilemma about which pricing index to rely on while calculating the annual increase in the prices for their product. To provide insights that can reduce this dilemma, a critical comparison of the Producer Price index and consumer price index is called for. In this study, the relation between the Producer Price Index (PPI) and Consumer Price Index (CPI) was investigated through a comparison between Turkey and UK. Unlike many other previous studies, this study tried to determine the dominant pricing approach in an economy by examining the relation between the producer and consumer prices. In this context, VAR, impulse-response, variance decomposition, and Granger causality tests were used for the analyses of time series data. The results of study showed that there was bidirectional causality between the producer and consumer prices in both countries. Therefore, it was asserted that businesses in both countries generally apply mixed pricing approach. The results thus provide some interesting insights that can aid marketing managers in their pricing decisions