Online Gaming Can Make a Better World: Jane McGonigal

With personal feelings put aside and sociological theoretical depictions brought to the forefront, it is interesting to compare some of Jane\u27s ideas with that of both Emile Durkheim and Max Weber. The theorist who stood out right away, being exemplified through Jane\u27s positive attitude claims on a much larger, macro-level scale, was Emile Durkheim. Jane\u27s ideas about transcending human\u27s as a resource through the social fabrics of gaming into something that might solve world hunger, poverty, and global warming was nothing short of functionalism at it\u27s best. Jane\u27s platform for social structure and maintaining positive social order is the online world, and online gaming is the vehicle for change

Introduction to the special issue on Antarctic oceanography in a changing world

Author Posting. © The Oceanography Society, 2012. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 25, no. 3 (2012): 14-17, doi:10.5670/oceanog.2012.68."Antarctic Oceanography in a Changing World" commemorates the twentieth anniversary of the commissioning of Research Vessel Icebreaker (RVIB) Nathaniel B. Palmer and the fifteenth anniversary of Antarctic Research and Supply Vessel (ARSV) Laurence M. Gould. The addition of these two Antarctic research vessels to the US fleet in the 1990s ushered in a new era of Antarctic oceanographic research for US scientists and their international collaborators. Although several US Coast Guard icebreakers in the Arctic and Antarctic waters conduct oceanographic research, their primary mission is icebreaking to facilitate access to land-based stations. The Palmer was, and remains to this day, the first and only purpose-built US research icebreaker in Antarctic service and has been serving sea-going scientists in all areas of Antarctica's seas for two decades. The Gould has afforded reliable year-round access to Palmer Station and has conducted oceanographic research in the Antarctic Peninsula area since 1997

Optimal Concentration of Information Content For Log-Concave Densities

An elementary proof is provided of sharp bounds for the varentropy of random vectors with log-concave densities, as well as for deviations of the information content from its mean. These bounds significantly improve on the bounds obtained by Bobkov and Madiman ({\it Ann. Probab.}, 39(4):1528--1543, 2011).Comment: 15 pages. Changes in v2: Remark 2.5 (due to C. Saroglou) added with more general sufficient conditions for equality in Theorem 2.3. Also some minor corrections and added reference

Postglacial fluctuations of Cordillera Darwin glaciers (southernmost Patagonia) reconstructed from Almirantazgo fjord sediments

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Quaternary Science Reviews 177 (2017):265-275, doi:10.1016/j.quascirev.2017.10.029.Most outlet glaciers of the Cordillera Darwin Icefield (CDI; Patagonia, 54⁰S) are currently transitioning from calving to land-based conditions. Whether this situation is unique to the modern climate or also occurred during the Holocene is entirely unknown. Here, we investigate the Holocene fluctuations of outlet glaciers from the northern flank of the CDI using a multi-proxy sedimentological and geochemical analysis of a 13.5 m long sediment core from Almirantazgo fjord. Our results demonstrate that sedimentation in Almirantazgo fjord started prior to 14,300 cal yr BP, with glacier-proximal deposits occurring until 13,500 cal yr BP. After 12,300 cal yr BP, most glaciers had retreated to land-locked locations and by 9800 cal yr BP, Almirantazgo fjord was a predominantly marine fjord environment with oceanographic conditions resembling the present-day setting. Our sediment record shows that during the first part of the Holocene, CDI glaciers were almost entirely land-based, with a possible re-advance at 7300–5700 cal yr BP. This is in clear contrast with the Neoglaciation, during which CDI glaciers rapidly re-advanced and shrank back several times, mostly in phase with the outlet glaciers of the Southern Patagonian Icefield (SPI). Two significant meltwater events, indicative of rapid glacier retreat, were identified at 3250–2700 and 2000–1200 cal yr BP, based on an increase in grain-size mode and related inorganic geochemical parameters. This interpretation is additionally supported by concomitant decreases in organic carbon of marine origin and in Cl counts (salinity), reflecting higher terrestrial input to the fjord and freshening of the fjord waters. Overall, our record suggests that CDI outlet glaciers advanced in phase with SPI glaciers during the Neoglaciation, and retreated far enough into their valleys twice to form large outwash plains. Our results also highlight the potential of fjord sediments to reconstruct glacier variability at high resolution on multi-millennial timescales.This research was supported by an EU Marie Curie FP6 postdoctoral fellowship to S.B., by National Geographic Grant 8379-07 (to S.B.), by COPAS Center FONDAP Grant 150100007 and COPAS Sur-Austral CONICYT PIA PFB31 (to C.L and S.P), and by IDEAL Center FONDAP Grant 15150003 (to C.L.)

D-optimal designs via a cocktail algorithm

A fast new algorithm is proposed for numerical computation of (approximate) D-optimal designs. This "cocktail algorithm" extends the well-known vertex direction method (VDM; Fedorov 1972) and the multiplicative algorithm (Silvey, Titterington and Torsney, 1978), and shares their simplicity and monotonic convergence properties. Numerical examples show that the cocktail algorithm can lead to dramatically improved speed, sometimes by orders of magnitude, relative to either the multiplicative algorithm or the vertex exchange method (a variant of VDM). Key to the improved speed is a new nearest neighbor exchange strategy, which acts locally and complements the global effect of the multiplicative algorithm. Possible extensions to related problems such as nonparametric maximum likelihood estimation are mentioned.Comment: A number of changes after accounting for the referees' comments including new examples in Section 4 and more detailed explanations throughou