A Charged Doubly Spinning Black Ring

This paper calculates the general form of a 5d metric when fundamental string and momentum charges are added. This is accomplished using the standard method of boosting and T-dualising a solution to Einstein's equations, where the solution has three Killing vectors and is expressed in a generic form. The thermodynamical properties of the charged solution are derived and the physical implications of the solution are then examined with the two-charge dual spinning black ring being used as an example.Comment: 22 pages, 4 figure

Effects of Acquisitions on R&D Inputs and Outputs

Making acquisitions, although a popular strategy, may not always lead to positive firm performance. Researchers have offered several explanations for this relationship. One is that acquisitions lead to lower investments in R&D and curtail the championing process whereby organization members internally promote new products and processes in firms. The current research found that acquisitions had negative effects on R&D intensity and patent intensity

Are Acquisitions a Poison Pill for Innovation?

The recent wave of acquisition activity may be damaging the innovative capabilities of American firms, thus making them less competitive in the global marketplace. In fact, acquisitions often serve as a substitute for innovation, which may cause further neglect of internal research and development (R&D) programs. Additionally, acquisitions often lead to increases in leverage, diversification, and absorb significant amounts of executive time, which may lead to reduced managerial commitment to innovation. In this article, evidence is presented suggesting that acquisition activity may result in reductions in R&D inputs and outputs. On average, the 191 firms in the sample reduced their allocations to R&D relative to their competitors following acquisitions. Furthermore, the firms also experienced reductions in the number of patents. Implications from this evidence are offered for executives and acquisition strategies. Specifically, based on our results, we propose that firms can compensate for the negative effects of acquisitions. Moreover, acquisitions, when properly planned and targeted, may enhance or complement a firm\u27s innovation processes. Firms should search for acquisitions that complement R&D projects, facilitate product commercialization and/or enhance their core competences

Inactivation of Streptomyces phage ɸC31 by 405 nm light : requirement for exogenous photosensitizers?

Exposure to narrowband violet-blue light around 405 nm wavelength can induce lethal oxidative damage to bacteria and fungi, however effects on viruses are unknown. As photosensitive porphyrin molecules are involved in the microbicidal inactivation mechanism, and since porphyrins are absent in viruses, then any damaging effects of 405 nm light on viruses might appear unlikely. This study used the bacteriophage ɸC31, as a surrogate for non-enveloped double-stranded DNA viruses, to establish whether 405 nm light can induce virucidal effects. Exposure of ɸC31 suspended in minimal media, nutrient-rich media, and porphyrin solution, demonstrated differing sensitivity of the phage. Significant reductions in phage titre occurred when exposed in nutrient-rich media, with ~3, 5 and 7-log10 reductions achieved after exposure to doses of 0.3, 0.5 and 1.4 kJ/cm2, respectively. When suspended in minimal media a 0.3 log10 reduction (P=0.012) occurred after exposure to 306 J/cm2: much lower than the 2.7 and >2.5 log10 reductions achieved with the same dose in nutrient-rich, and porphyrin-supplemented media, suggesting inactivation is accelerated by the photo-activation of light-sensitive components in the media. This study provides the first evidence of the interaction of narrowband 405 nm light with viruses, and demonstrates that viral susceptibility to 405 nm light can be significantly enhanced by involvement of exogenous photosensitive components. The reduced susceptibility of viruses in minimal media, compared to that of other microorganisms, provides further evidence that the antimicrobial action of 405 nm light is predominantly due to the photo-excitation of endogenous photosensitive molecules such as porphyrins within susceptible microorganisms

A Black Ring with two Angular Momenta in Taub-NUT

We use the recently-constructed explicit duality transformation that relates a rotating anti-D6-D4-D2-D0 black hole solution to a rotating M5-M2-P black string to construct a non-supersymmetric black ring in Taub-NUT that has two angular momenta, as well as M2 charges and M5 dipole moments. This is the first black ring solution that has both dipole charges and rotation along the S^2 of the horizon, and hence can be thought of as the "Pomeransky-Senkov" version of the M5-M2 black ring in Taub-NUT. Its physics should provide a testing ground for the applicability of the blackfold approach to charged rotating black branes, and should elucidate the phase space of charged dipole rings in various backgrounds.Comment: 20 pages, LaTe

Differential transcription of expanded gene families in central carbon metabolism of Streptomyces coelicolor A3(2)

Background: Streptomycete bacteria are prolific producers of specialised metabolites, many of which have clinically relevant bioactivity. A striking feature of their genomes is the expansion of gene families that encode the same enzymatic function. Genes that undergo expansion events, either by horizontal gene transfer or duplication, can have a range of fates: genes can be lost, or they can undergo neo-functionalisation or sub-functionalisation. To test whether expanded gene families in Streptomyces exhibit differential expression, an RNA-Seq approach was used to examine cultures of wild-type Streptomyces coelicolor grown with either glucose or tween as the sole carbon source. Results: RNA-Seq analysis showed that two-thirds of genes within expanded gene families show transcriptional differences when strains were grown on tween compared to glucose. In addition, expression of specialised metabolite gene clusters (actinorhodin, isorenieratane, coelichelin and a cryptic NRPS) was also influenced by carbon source. Conclusions: Expression of genes encoding the same enzymatic function had transcriptional differences when grown on different carbon sources. This transcriptional divergence enables partitioning to function under different physiological conditions. These approaches can inform metabolic engineering of industrial Streptomyces strains and may help develop cultivation conditions to activate the so-called silent biosynthetic gene clusters

Corporate governance and financial constraints on strategic turnarounds

The paper extends the Robbins and Pearce (1992) two-stage turnaround response model to include governance factors. In addition to the retrenchment and recovery, the paper proposes the addition of a realignment stage, referring specifically to the re-alignment of expectations of principal and agent groups. The realignment stage imposes a threshold that must be crossed before the retrenchment and hence recovery stage can be entered. Crossing this threshold is problematic to the extent that the interests of governance-stakeholder groups diverge in a crisis situation. The severity of the crisis impacts on the bases of strategy contingent asset valuation leading to the fragmentation of stakeholder interests. In some cases the consequence may be that management are prevented from carrying out turnarounds by governance constraints. The paper uses a case study to illustrate these dynamics, and like the Robbins and Pearce study, it focuses on the textile industry. A longitudinal approach is used to show the impact of the removal of governance constraints. The empirical evidence suggests that such financial constraints become less serious to the extent that there is a functioning market for corporate control. Building on governance research and turnaround literature, the paper also outlines the general case necessary and sufficient conditions for successful turnarounds

Do the type and number of blockholders influence R&D investments? : new evidence from Spain

Using data from 3,638 Spanish firms between 1996 and 2000, this article studies the relationship between the presence of large shareholders in the ownership structure of firms and R&D investment. Consistent with our theoretical contention, our results indicate that the impact of large shareholders on the R&D investment is (1) negative when blockholders are banks, (2) positive when blockholders are non-financial corporations and (3) null when blockholders are individuals. In addition, we find a systematic negative relationship between the number of blockholders and R&D investment. Finally, we extend our study by analysing the influence that the combined effect between blockholder type and R&D investment has on the firm’s economic performance. Results of this work provide relevant implications for policy makers and academic research.Publicad

Thirty Years After Michael E. Porter: What Do We Know About Business Exit?

Although a business exit is an important corporate change initiative, the buyer’s side seems to be more appealing to management researchers than the seller’s because acquisitions imply growth, i.e., success. Yet from an optimistic viewpoint, business exit can effectively create value for the selling company. In this paper we attempt to bring the relevance of the seller’s side back into our consciousness by asking: What do we know about business exit? We start our exploration with Porter (1976), focusing on literature that investigates the antecedents of, barriers to, and outcomes of business exit. We also include studies from related fields such as finance and economics.1 Through this research we determine three clusters of findings: factors promoting business exit, exit barriers, and exit outcomes. Overall, it is the intention of this paper to highlight the importance of business exit for research and practice. Knowing what we know about business exits and their high financial value we should bear in mind that exit need not mean failure but a new beginning for a corporation