The Adverse Environmental and Socio-Cultural Effects of Tourism in Vietnam

An examination of the adverse environmental and socio-cultural impacts of tourism in Vietnam

Policy Options for State Pension Systems and Their Impact on Plan Liabilities

We calculate the present value of state pension liabilities under existing policies, and separately under policy changes that would affect pension payouts including cost of living adjustments (COLAs), retirement ages, and buyout schedules for early retirement. Liabilities if plans were frozen as of June 2009 would be $3.2 trillion if capitalized using taxable municipal curves, which credit states for a possibility of default in the same states of the world as general obligation debt, and$4.4 trillion using the Treasury curve. Under the typical actuarial method of recognizing future service and wage increases, liabilities are $3.6 trillion and$5.2 trillion using municipal curves and Treasury curves respectively. Compared to $1.8 trillion in pension fund assets, the baseline level of unfunded liabilities is therefore around$3 trillion under Treasury rates. A one percentage point reduction in COLAs would reduce total liabilities by 9‐11%, implementing actuarially fair early retirement could reduce them by 2‐5%, and raising the retirement age by one year would reduce them by 2‐4%. Even relatively dramatic policy changes, such as the elimination of COLAs or the implementation of Social Security retirement age parameters, would leave liabilities around $1.5 trillion more than plan assets under Treasury discounting. This suggests that taxpayers will bear the lion's share of the costs associated with the legacy liabilities of state DB pension plans.

Dynamic Commercialization Strategies for Disruptive Technologies: Evidence from the Speech Recognition Industry

When start-up innovation involves a potentially disruptive technology—initially lagging in the predominant performance metric, but with a potentially favorable trajectory of improvement—incumbents may be wary of engaging in cooperative commercialization with the start-up. While the prevailing theory of disruptive innovation suggests that this will lead to (exclusively) competitive commercialization and the eventual replacement of incumbents, we consider a dynamic strategy involving product market entry before switching to a cooperative commercialization strategy. Empirical evidence from the automated speech recognition industry from 1952 to 2010 confirms our main hypothesis.Wharton School. Mack Institute for Innovation ManagementSloan School of Management (Roberts E-Center Fund

Dynamic Commercialization Strategies for Disruptive Technologies: Evidence From the Speech Recognition Industry

When start-up innovation involves a potentially disruptive technology—initially lagging in the predominant performance metric, but with a potentially favorable trajectory of improvement—incumbents may be wary of engaging in cooperative commercialization with the start-up. While the prevailing theory of disruptive innovation suggests that this will lead to (exclusively) competitive commercialization and the eventual replacement of incumbents, we consider a dynamic strategy involving product market entry before switching to a cooperative commercialization strategy. Empirical evidence from the automated speech recognition industry from 1952 to 2010 confirms our main hypothesis

Financial Valuation of PBGC Insurance with Market-Implied Default Probabilities

In this paper, we use financial valuation techniques to measure the unfunded liabilities associated with the Pension Benefit Guaranty Corporation (PBGC) single-employer pension insurance program. This is an alternative approach to the calculations of expected future PBGC payouts in the PBGC exposure reports. The PBGC insurance is akin to an exchange option, a financial instrument that allows a party to exchange one risky asset for another. Calculating the value of this option for each PBGC-covered plan provides a measure of the fair market price of the PBGC guarantee that is consistent with the finance principles of risk-neutral pricing. That is, the market valuation method reflects the fact that bad outcomes tend to coincide with times when losses are particularly painful. The valuation we perform also reflects the fact that PBGC insurance is triggered only in the case of bankruptcy by drawing on the default probabilities implied by the credit ratings of insured plans. Under the baseline parameters, the PBGC’s insurance of the unfunded liabilities has a financial value of $358 billion, net of the estimated present value of PBGC premiums

Reconstructing annual inflows to the headwater catchments of the Murray River, Australia, using the Pacific Decadal Oscillation

The Pacific Decadal Oscillation (PDO) is a major forcing of inter-decadal to quasi-centennial variability of the hydroclimatology of the Pacific Basin. Its effects are most pronounced in the extra-tropical regions, while it modulates the El Nino Southern Oscillation (ENSO), the largest forcing of global inter-annual climate variability. PalaeoPDO indices are now available for at least the past 500 years. Here we show that the \u3e500 year PDO index of Shen et al. (2006) is highly correlated with inflows to the headwaters of Australia\u27s longest river system, the Murray-Darling. We then use the PDO to reconstruct annual inflows to the Murray River back to A.D. 1474. These show penta-decadal and quasi-centennial cycles of low inflows and a possible 500 year cycle of much greater inflow variability. Superimposed on this is the likely influence of recent anthropogenic global warming. We believe this may explain the exceptionally low inflows of the past decade, the lowest of the previous 529 years

Effective use of a horizontally-transferred pathway for dichloromethane catabolism requires post–transfer refinement

When microbes acquire new abilities through horizontal gene transfer, the genes and pathways must function under conditions with which they did not coevolve. If newly-acquired genes burden the host, their utility will depend on further evolutionary refinement of the recombinant strain. We used laboratory evolution to recapitulate this process of transfer and refinement, demonstrating that effective use of an introduced dichloromethane degradation pathway required one of several mutations to the bacterial host that are predicted to increase chloride efflux. We then used this knowledge to identify parallel, beneficial mutations that independently evolved in two natural dichloromethane-degrading strains. Finally, we constructed a synthetic mobile genetic element carrying both the degradation pathway and a chloride exporter, which preempted the adaptive process and directly enabled effective dichloromethane degradation across diverse Methylobacterium environmental isolates. Our results demonstrate the importance of post–transfer refinement in horizontal gene transfer, with potential applications in bioremediation and synthetic biology. DOI: http://dx.doi.org/10.7554/eLife.04279.00

Massive Mitochondrial Gene Transfer in a Parasitic Flowering Plant Clade

Recent studies have suggested that plant genomes have undergone potentially rampant horizontal gene transfer (HGT), especially in the mitochondrial genome. Parasitic plants have provided the strongest evidence of HGT, which appears to be facilitated by the intimate physical association between the parasites and their hosts. A recent phylogenomic study demonstrated that in the holoparasite Rafflesia cantleyi (Rafflesiaceae), whose close relatives possess the world's largest flowers, about 2.1% of nuclear gene transcripts were likely acquired from its obligate host. Here, we used next-generation sequencing to obtain the 38 protein-coding and ribosomal RNA genes common to the mitochondrial genomes of angiosperms from R. cantleyi and five additional species, including two of its closest relatives and two host species. Strikingly, our phylogenetic analyses conservatively indicate that 24%–41% of these gene sequences show evidence of HGT in Rafflesiaceae, depending on the species. Most of these transgenic sequences possess intact reading frames and are actively transcribed, indicating that they are potentially functional. Additionally, some of these transgenes maintain synteny with their donor and recipient lineages, suggesting that native genes have likely been displaced via homologous recombination. Our study is the first to comprehensively assess the magnitude of HGT in plants involving a genome (i.e., mitochondria) and a species interaction (i.e., parasitism) where it has been hypothesized to be potentially rampant. Our results establish for the first time that, although the magnitude of HGT involving nuclear genes is appreciable in these parasitic plants, HGT involving mitochondrial genes is substantially higher. This may represent a more general pattern for other parasitic plant clades and perhaps more broadly for angiosperms.Organismic and Evolutionary Biolog

Principal component analysis and biochemical characterization of protein and starch reveal primary targets for improving sorghum grain

Limited progress has been made on genetic improvement of the digestibility of sorghum grain because of variability among different varieties. In this study, we applied multiple techniques to assess digestibility of grain from 18 sorghum lines to identify major components responsible for variability. We also identified storage proteins and enzymes as potential targets for genetic modification to improve digestibility. Results from principal component analysis revealed that content of amylose and total starch, together with protein digestibility (PD), accounted for 94% of variation in digestibility. Control of amylose content is understood and manageable. Up-regulation of genes associated with starch accumulation is clearly a future target for improving digestibility. To identify proteins that might be targets for future modification, meal from selected lines was digested in vitro with pancreatin in parallel with pepsin and α-amylase. The %PD was influenced by both the nature of the protein matrix and protein body packaging. Owing to its ability to form oligomers, the 20 kDa γ-kafirin was more resistant to digestion than counterparts lacking this ability, making it a target for down-regulation. Greater understanding of interactions among the three traits identified by principal component analysis is needed for both waxy and non-waxy varieties