Subpicosecond emission studies of bacterial reaction centers

The spontaneous emission of reaction centers from native and mutated Rhodobacter sphaeroides and from wild type Chloroflexus aurantiacus is investigated by fluorescence up-conversion with high temporal resolution. The time constant of 0.9 ps previously observed in transient absorption experiments on wild type reaction centers of Rhodobacter sphaeroides does not appear in the emission experiment. However, all investigated reaction centers display a biexponential decay of the emission with time constants in the 2 ps to 25 ps range. The experimental results are discussed within the frame of different reaction models including a possible sample heterogeneity or a transient electron transfer to the inactive pigment branch

Instability and network effects in innovative markets

We consider a network of interacting agents and we model the process of choice on the adoption of a given innovative product by means of statistical-mechanics tools. The modelization allows us to focus on the effects of direct interactions among agents in establishing the success or failure of the product itself. Mimicking real systems, the whole population is divided into two sub-communities called, respectively, Innovators and Followers, where the former are assumed to display more influence power. We study in detail and via numerical simulations on a random graph two different scenarios: no-feedback interaction, where innovators are cohesive and not sensitively affected by the remaining population, and feedback interaction, where the influence of followers on innovators is non negligible. The outcomes are markedly different: in the former case, which corresponds to the creation of a niche in the market, Innovators are able to drive and polarize the whole market. In the latter case the behavior of the market cannot be definitely predicted and become unstable. In both cases we highlight the emergence of collective phenomena and we show how the final outcome, in terms of the number of buyers, is affected by the concentration of innovators and by the interaction strengths among agents.Comment: 20 pages, 6 figures. 7th workshop on "Dynamic Models in Economics and Finance" - MDEF2012 (COST Action IS1104), Urbino (2012

An exploratory study on the potential of social enterprise to act as the institutional glue of network governance

This study combines two topics of contemporary salience for public administration: social enterprise and governance networks. While operating at different levels, both are institutions which attempt to draw together the three pillars of state, market, and civil society. Nevertheless, the respective literatures focus on particular aspects of the three pillars. We connect the two concepts and suggest that some social enterprises can act as the institutional glue of networks due to their ability to benefit organizations in each of the three sectors. This requires social enterprises to have the managerial capacity to diffuse social know-how, and is facilitated by the trust of other organizations and a supportive policy framework. The links are explicated at the conceptual level before providing evidence from South Korea and the UK. Finally, research propositions are offered, which suggest new avenues for future research

Consumer Complaints and Company Market Value

Consumer complaints affect company market value and common sense suggests that a negative impact is expected. However, do complaints always negatively impact company market value? We hypothesize in this study that complaints may have a non-linear effect on market value. Positive (e.g. avoiding high costs to solve complaints) and negative (e.g. speedy and intense diffusion) tradeoffs may occur given the level of complaints. To test our non-linear hypothesis, a panel data was collected from cell phone service providers from 2005 to 2013. The results supported our tradeoff rationale. Low levels of complaints allow for companies to increase market value, while high levels of complaints cause increasing harm to market value. The sample, model and period considered in this study, indicates a level of 0.49 complaints per thousand consumers as the threshold for a shift in tradeoffs. The effects on market value become increasingly negative when trying to make reductions to move below this level, due to negative tradeoffs

Investigating web-based recruitment sources: Employee testimonials vs word-of-mouse

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OCIS codes: (240.6680) Surface plasmons, (050.1950) Diffraction gratings, (260.3800) Lumi-nescence

Abstract: We demonstrate a novel functionality of semiconductor nanowires as local sources for surface plasmon polaritons (SPPs). Photoexcited semiconductor nanowires decay non-radiatively exciting SPPs when they are on top of a metallic surface. We have investigated the anisotropic excitation of SPPs by nanowires by placing individual InP nanowires inside gold bullseye gratings. The gratings serve to couple SPPs to free space radiation that is detected with a scanning confocal microscope. The circular geometry of the grating allows to conclude that SPPs are preferentially generated in the direction along the nanowire axis

A content analysis of gambling operators’ Twitter accounts at the start of the English premier league football season

The use of social media is now an established strategy to engage and maintain customer loyalty. The purpose of the present study was to examine the Twitter accounts of ten of the largest online sports betting operators in the UK to determine what marketing strategies were employed. More specifically, this study analyzed 3375 tweets posted by the operators during the opening weekend of the 2018–2019 English Premier League football season using a content analysis methodology. The results demonstrated that multiple strategies, including hashtags, were used to link gambling operator tweets with major sporting events, and the use of numerous promotional campaigns. Notably, over 90% of the tweets contained no responsible gambling information. The quantity and content of social media posts underline the need for a review of the current advertising regulations in the UK. Further research should examine how exposure to sports betting social media marketing influences gambling behavior