On unfolding lattice polygons/trees and diameter-4 trees

We consider the problems of straightening polygonal trees and convexifying polygons by continuous motions such that rigid edges can rotate around vertex joints and no edge crossings are allowed. A tree can be straightened if all its edges can be aligned along a common straight line such that each edge points "away" from a designated leaf node. A polygon can be convexified if it can be reconfigured to a convex polygon. A lattice tree (resp. polygon) is a tree (resp. polygon) containing only edges from a square or cubic lattice. We first show that a 2D lattice chain or a 3D lattice tree can be straightened efficiently in O(n) moves and time, where n is the number of tree edges. We then show that a 2D lattice tree can be straightened efficiently in O(n2) moves and time. Furthermore, we prove that a 2D lattice polygon or a 3D lattice polygon with simple shadow can be convexified efficiently in O(n2) moves and time. Finally, we show that two special classes of diameter-4 trees in two dimensions can always be straightened

Re-Branding Alternative Tourism in the Caribbean: The Case for ‘Slow Tourism’

Slow tourism represents a progressive genre of alternative tourism for remote locales in the Caribbean beyond mass-tourism complexes. We propose this new form of slow tourism as a viable promotional identity for alternative tourist offerings, which are in need of re-branding, through the decentralized medium of information technologies. A further contribution to this new construct\u27s identity is our recognition of the potential for the Caribbean diaspora to participate as stakeholders in slow tourism ventures in under-developed spaces of the Caribbean that lack the requisite resources and bundle of social and economic advantages that mass-tourism relies upon. Thus, the unevenness of tourism-driven development in the Caribbean can be countered progressively, and more inclusively, than in times past. In addition to developing the theoretical construct of slow tourism, we offer several prototype examples to demonstrate quality offerings already in praxis

Avian influenza H5N1 in viverrids: implications for wildlife health and conservation

The Asian countries chronically infected with avian influenza A H5N1 are ‘global hotspots’ for biodiversity conservation in terms of species diversity, endemism and levels of threat. Since 2003, avian influenza A H5N1 viruses have naturally infected and killed a range of wild bird species, four felid species and a mustelid. Here, we report fatal disseminated H5N1 infection in a globally threatened viverrid, the Owston's civet, in Vietnam, highlighting the risk that avian influenza H5N1 poses to mammalian and avian biodiversity across its expanding geographic range

Newly Developed Stepwise Electroless Deposition Enables a Remarkably Facile Synthesis of Highly Active and Stable Amorphous Pd Nanoparticle Electrocatalysts for Oxygen Reduction Reaction

This paper reports on highly active and stable amorphous Pd nanoparticle electrocatalysts for the oxygen reduction reaction. The amorphous catalysts were synthesized by a remarkably facile and quick electroless deposition process newly developed in this study (process time <5 min). An electrode substrate (glassy carbon, carbon cloth) was sequentially dipped for 10 s into two separate solutions of a reducing agent (sodium hypophosphite (NaH₂PO₂)) and Pd ions to deposit amorphous Pd nanoparticles containing phosphorus (Pd–P). By repeating the deposition cycles, the specific and mass activities of the Pd nanoparticles can be actively tuned. Owing to the nanoscale amorphous nature, the obtained Pd–P nanoparticle electrocatalysts exhibited superior specific and mass activities compared with crystalline Pd nanoparticles synthesized by another reducing agent (N₂H₄) and commercial Pt-loaded carbon (Pt/C) and Pd-loaded carbon (Pd/C). The specific and mass activities of the amorphous Pd–P nanoparticles were over 4.5 times and 2.6 times higher than previously reported values of Pd and Pt catalysts

Second Thoughts: Multiple P300s Elicited by a Single Stimulus

In a previous report (Johnson & Donchin, 1978), we manipulated the discriminability of tone pairs that delivered feedback information in a time‐estimation paradigm. As in other experiments using feedback stimuli, the event‐related potentials elicited by these stimuli did not return to baseline in the 800‐ms poststimulus interval. Since we were interested in this “Slow Wave\u27’activity, the poststimulus interval was lengthened to 1500 ms. Averages revealed that a second positive peak was present for some of the individual subjects. To investigate this activity further, the filtered singletrial waveforms were inspected visually. These data were characterized by the presence of one, and occasionally two, positive peaks, with highly variable latencies, following the P300. These peaks were indistinguishable in frequency and general appearance from the P300s elicited by the feedback stimuli. After latency adjusting the waveforms on the peak of the second positive wave, amplitude and latency were quantified. Whereas P300 amplitude was directly related to stimulus discriminability and positive feedback elicited larger P300s than negative feedback, the amplitude of the second positive wave was constant across levels of discriminability and the same for both types of feedback. In contrast, the latencies of both waves were inversely related to stimulus discriminability and shorter following positive feedback than negative feedback. Evidence is presented to support our contention that these additional positive peaks represent P300 activity. The data are discussed in terms of what these multiple P300s reveal about human information processing

Evolution of New Genotype of West Nile Virus in North America

Previous studies of North American isolates of West Nile virus (WNV) during 1999–2005 suggested that the virus had reached genetic homeostasis in North America. However, genomic sequencing of WNV isolates from Harris County, Texas, during 2002–2009 suggests that this is not the case. Three new genetic groups have been identified in Texas since 2005. Spread of the southwestern US genotype (SW/WN03) from the Arizona/Colorado/northern Mexico region to California, Illinois, New Mexico, New York, North Dakota, and the Texas Gulf Coast demonstrates continued evolution of WNV. Thus, WNV continues to evolve in North America, as demonstrated by selection of this new genotype. Continued surveillance of the virus is essential as it continues to evolve in the New World