MM Algorithms for Minimizing Nonsmoothly Penalized Objective Functions

In this paper, we propose a general class of algorithms for optimizing an extensive variety of nonsmoothly penalized objective functions that satisfy certain regularity conditions. The proposed framework utilizes the majorization-minimization (MM) algorithm as its core optimization engine. The resulting algorithms rely on iterated soft-thresholding, implemented componentwise, allowing for fast, stable updating that avoids the need for any high-dimensional matrix inversion. We establish a local convergence theory for this class of algorithms under weaker assumptions than previously considered in the statistical literature. We also demonstrate the exceptional effectiveness of new acceleration methods, originally proposed for the EM algorithm, in this class of problems. Simulation results and a microarray data example are provided to demonstrate the algorithm's capabilities and versatility.Comment: A revised version of this paper has been published in the Electronic Journal of Statistic

Global secular changes in different tidal high water, low water and range levels

Tides exert a major control on the coastal zone by influencing high sea levels and coastal flooding, navigation, sediment dynamics, and ecology. Therefore, any changes to tides have wide ranging and important implications. In this paper, we uniquely assess secular changes in 15 regularly used tidal levels (five high water, five low water and five tidal ranges), which have direct practical applications. Using sea level data from 220 tide gauge sites, we found changes have occurred in all analyzed tidal levels in many parts of the world. For the tidal levels assessed, between 36% and 63% of sites had trends significantly different (at 95% confidence level) from zero. At certain locations, the magnitude of the trends in tidal levels were similar to trends in mean sea level over the last century, with observed changes in tidal range and high water levels of over 5 mm/yr and 2 mm/yr, respectively. More positive than negative trends were observed in tidal ranges and high water levels, and vice versa for low water levels. However we found no significant correlation between trends in mean sea level (MSL) and any tidal levels. Spatially coherent trends were observed in some regions, including the north-east Pacific, German Bight and Australasia, and we also found that differences in trends occur between different tidal levels. This implies that analyzing different tidal levels is important. Because changes in the tide are widespread and of similar magnitude to MSL rise at a number sites, changes in tides should be considered in coastal risk assessments

Abridged bibliography of photographic interpretation : selected with emphasis upon keys, techniques, and research

This bibliography, PIC Report No. 102A/50, is a literature review of the applications of aerial photography. It is a classified list covering applications for archaeology, engineering, forestry, geography, geology, soil science, and the study of vegetation. The copy used to create this digital document was borrowed from the Maury Oceanographic Library, Stennis Space Center, MS

Advances in mechanisms of genetic instability related to hereditary neurological diseases

Substantial progress has been realized in the past several years in our understanding of the molecular mechanisms responsible for the expansions and deletions (genetic instabilities) of repeating tri-, tetra- and pentanucleotide repeating sequences associated with a number of hereditary neurological diseases. These instabilities occur by replication, recombination and repair processes, probably acting in concert, due to slippage of the DNA complementary strands relative to each other. The biophysical properties of the folded-back repeating sequence strands play a critical role in these instabilities. Non-B DNA structural elements (hairpins and slipped structures, DNA unwinding elements, tetraplexes, triplexes and sticky DNA) are described. The replication mechanisms are influenced by pausing of the replication fork, orientation of the repeat strands, location of the repeat sequences relative to replication origins and the flap endonuclease. Methyl-directed mismatch repair, nucleotide excision repair, and repair of damage caused by mutagens are discussed. Genetic recombination and double-strand break repair advances in Escherichia coli, yeast and mammalian models are reviewed. Furthermore, the newly discovered capacities of certain triplet repeat sequences to cause gross chromosomal rearrangements are discussed

Surfaces, depths and hypercubes: Meyerholdian scenography and the fourth dimension

An appreciation of Meyerhold’s engagement with theatrical space is fundamental to understanding his directorial and pedagogic practice. This article begins by establishing Meyerhold’s theoretical and practical engagement with theatre as a fundamentally scenographic process, arguing for a reconceptualisation of the director as ‘director-scenographer’. Focusing on the construction of depth and surface in Meyerholdian theatre, the article goes on to identify trends in the director’s approach to space, with an emphasis on the de-naturalisation of depth on stage. This denaturalisation is seen as taking three forms: the rejection of depth as a prerequisite in theatrical space, the acknowledgement of the two-dimensional surface as surface, and the restructuring of depth space into a series of restricted planes. The combination of these trends indicates a consistent and systematic process of experimentation in Meyerhold’s work. In addition, this emphasis on depth and surface, and the interaction between the two, also highlights the contextualisation of Meyerhold’s practice within the visual, philosophical and scientific culture of the early twentieth century, echoing the innovations in n-dimensional geometry and particularly, the model of the fourth spatial dimension seen in the work of Russian philosopher P. D. Ouspensky