1,735 research outputs found
Design specification for a list processing system
There are no author-identified significant results in this report
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Preliminary site report for the 2005 ICDP-USGS deep corehole in the Chesapeake Bay impact crater
First report for the ICDP-USGS 1.7-km-deep corehole drilled into the central part of the Chesapeake Bay impact crater during 2005
The Influence of Enhanced Post-Glacial Coastal Margin Productivity on the Emergence of Complex Societies
Abstract We analyze the dynamics of post-glacial coastal margin (CM) productivity and explore how it affected the emergence of six complex CM societies. Following deglaciation, global relative sea level stabilized after ~7000 BP and CM productivity significantly increased in many areas. Primary and secondary productivity (fish) likely increased by an order of magnitude or more. Aquatic animals were readily available in the CM providing sources of polyunsaturated omega-3 fatty acids, high quality protein, and nutrients, especially essential to human nutrition. In all six case studies, mature CMs appear to have been occupied by Neolithic agricultural and fishing villages within ~500 years of sea-level stabilization. Within a few hundred years population densities increased and roughly a millennium later social ranking and monumental architecture appeared. Sea-level stabilization and increased CM productivity in conjunction with agricultural intensification in lower alluvial floodplains were major contributors to the origins of many complex CM societies. Keyword
Fine-tuning implications for complementary dark matter and LHC SUSY searches
The requirement that SUSY should solve the hierarchy problem without undue
fine-tuning imposes severe constraints on the new supersymmetric states. With
the MSSM spectrum and soft SUSY breaking originating from universal scalar and
gaugino masses at the Grand Unification scale, we show that the low-fine-tuned
regions fall into two classes that will require complementary collider and dark
matter searches to explore in the near future. The first class has relatively
light gluinos or squarks which should be found by the LHC in its first run. We
identify the multijet plus E_T^miss signal as the optimal channel and determine
the discovery potential in the first run. The second class has heavier gluinos
and squarks but the LSP has a significant Higgsino component and should be seen
by the next generation of direct dark matter detection experiments. The
combined information from the 7 TeV LHC run and the next generation of direct
detection experiments can test almost all of the CMSSM parameter space
consistent with dark matter and EW constraints, corresponding to a fine-tuning
not worse than 1:100. To cover the complete low-fine-tuned region by SUSY
searches at the LHC will require running at the full 14 TeV CM energy; in
addition it may be tested indirectly by Higgs searches covering the mass range
below 120 GeV.Comment: References added. Version accepted for publication in JHE
The amphioxus genome and the evolution of the chordate karyotype
Lancelets ('amphioxus') are the modern survivors of an ancient chordate lineage, with a fossil record dating back to the Cambrian period. Here we describe the structure and gene content of the highly polymorphic approx520-megabase genome of the Florida lancelet Branchiostoma floridae, and analyse it in the context of chordate evolution. Whole-genome comparisons illuminate the murky relationships among the three chordate groups (tunicates, lancelets and vertebrates), and allow not only reconstruction of the gene complement of the last common chordate ancestor but also partial reconstruction of its genomic organization, as well as a description of two genome-wide duplications and subsequent reorganizations in the vertebrate lineage. These genome-scale events shaped the vertebrate genome and provided additional genetic variation for exploitation during vertebrate evolution
Ribosomal oxygenases are structurally conserved from prokaryotes to humans
2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases
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1974
History of Golf (1) The Nine Toughest Holes in the World (2) Stockie Madness (3) Bartender, One More Round for Pythium (3) Panel: 1973 Turf Problems in Review - 1974 Possible Remedies (A1-A12) Movement of Water to a Holding Pond (A13) Maintenance of Low Budget, Short Season Golf Courses (A16) Turfgrass Fertilization (A18) Determining Turfgrass Fertilizer Needs (A25) Shortage of Plant Food and How to Adjust to Supply and Cost (A29) Panel: Tricalcium Arsenate - Use and Abuse (A33-A46) Operating and Maintaining Municipal Golf Courses (A48) Maintenance of a High Budget Golf Course (A51) Trends in Agricultural Education and Where Are the Emphases (A58) Maintenance of Municipal Parks and Recreation Areas (A60) Maintenance of Grass Tennis Courts (A63) Transition from Natural to Artificial Turf (A67) Plant materials for Outlying Areas (A71) Care of University Grounds (A76) Maintenance of Industrial Sites (A79) Turfgrass Diseases and Systemic Fungicides (A81) A Look at the Future (A 84) Watering of Golf Course Turf (A92
Migraine aura: retracting particle-like waves in weakly susceptible cortex
Cortical spreading depression (SD) has been suggested to underlie migraine aura. Despite a precise match in speed, the spatio-temporal patterns of SD and aura symptoms on the cortical surface ordinarily differ in aspects of size and shape. We show that this mismatch is reconciled by utilizing that both pattern types bifurcate from an instability point of generic reaction-diffusion models. To classify these spatio-temporal pattern we suggest a susceptibility scale having the value [sigma]=1 at the instability point. We predict that human cortex is only weakly susceptible to SD ([sigma]<1), and support this prediction by directly matching visual aura symptoms with anatomical landmarks using fMRI retinotopic mapping. We discuss the increased dynamical repertoire of cortical tissue close to [sigma]=1, in particular, the resulting implications on migraine pharmacology that is hitherto tested in the regime ([sigma]>>1), and potentially silent aura occurring below a second bifurcation point at [sigma]=0 on the susceptible scale
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