128,869 research outputs found
A Single-armed Manta-board as a New Diver-controlled Planing Board and Its Use for Underwater Surveys
Due to inadequacies of previous underwater towing techniques and the special needs of a recent underwater survey, a modified mania-board technique was developed. With this new technique, the diver holds on to the manta-board with one arm; consequently, the board is referred to as a single-armed manta-board (sam-board). The sam-board proved inexpensive and highly maneuverable, allowing the divers to freely collect samples or record information. Through some experimenting with the board and changing some of the variables, such as rope lengths, towing speeds, etc., a highly efficient towing method can be achieved. Preplanning and strict diving safety procedures must, however, be implemented to assure efficiency. This paper presents the materials, guidelines for board construction, equipment, and preplanning and diving safety procedures necessary for the sam-board towing operation
Seasonal Biomass and Carbohydrate Allocation Patterns in Southern Minnesota Curlyleaf Pondweed Populations
Four southern Minnesota populations of curlyleaf pondweed
(
Potamogeton crispus
L.) were sampled monthly from
January 2001 to November 2002 to determine seasonal phenological,
biomass, and carbohydrate allocation patterns.
Low periods of carbohydrate storage in the seasonal phenological
cycle indicate potentially vulnerable periods in the
plant’s life cycle and may be the ideal time to initiate management
and control efforts
Exclusive pi^+ production at HERMES
Hard exclusive production in deep inelastic lepton scattering provides access
to the unknown Generalized Parton Distributions (GPDs) of the nucleon. At
HERMES, different observables for hard exclusive pi^+ production have been
measured with a 27.6 GeV positron beam on an internal hydrogen gas target.
First preliminary results for the unpolarized ep->enpi^+ total cross section
for 1.5<Q^2<10.5 GeV^2 and for 0.02<x<0.8 are presented and compared to GPD
calculations. The final result for the single-spin asymmetry using a
longitudinal polarized target is also reported.Comment: 5 pages, 3 figures, contribution to the XII International Workshop on
Deep Inelastic Scattering, April 14-18, 2004, Strbske Pleso, Slovaki
An Actuarial Analysis of the Production Function of Major League Baseball
The majority of major league baseball production function studies have utilized data (nonstandardized and standardized) from only one baseball season. This research study utilized data from the 1980-1984 baseball seasons. The results indicate that factors contributing to victories fluctuate. Consistent with prior research, this study found batting average, manager\u27s career win-loss record and the strike-out-to-walk ratio to be the most significant factors contributing to victories. Inconsistent with prior research, this study found that fielding average can also be significant
NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 9: Information intermediaries and the transfer of aerospace Scientific and Technical Information (STI): A report from the field
From the NASA/DOD survey data, there can be no way of inferring what strategy for knowledge transfer is best; indeed, given the fact that the respondents were all presumably well qualified professionals, the data tend to call into serious question the idea that any one model might meet the needs of more than a distinct minority of possible users. The evidence to date appears to reinforce the concept that different information environments take many different shapes, and interact with each other and with formal data transmission sources in many different and equally valuable ways. Any overall strategy for improving the effectiveness and efficiency of scientific and technical information sharing must take this divergence into account, and work toward the creation of systems that reinforce true interactive knowledge utilization rather than simply disseminating data
Proton network flexibility enables robustness and large electric fields in the ketosteroid isomerase active site
Hydrogen bond networks play vital roles in biological functions ranging from
protein folding to enzyme catalysis. Here we combine electronic structure
calculations and ab initio path integral molecular dynamics simulations, which
incorporate both nuclear and electronic quantum effects, to show why the
network of short hydrogen bonds in the active site of ketosteroid isomerase is
remarkably robust to mutations along the network and how this gives rise to
large local electric fields. We demonstrate that these properties arise from
the network's ability to respond to a perturbation by shifting proton positions
and redistributing electronic charge density. This flexibility leads to small
changes in properties such as the partial ionization of residues and
isotope effects upon mutation of the residues, consistent with recent
experiments. This proton flexibility is further enhanced when an extended
hydrogen bond network forms in the presence of an intermediate analog, which
allows us to explain the chemical origins of the large electric fields in the
enzyme's active site observed in recent experiments.Comment: 13 pages, 10 figures (7 main text and 3 SI
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