2,449 research outputs found
THE CONTRIBUTION OF THE COAST TO THE SOUTH CAROLINA ECONOMY
The South Carolina counties classified as coastal are Beaufort, Berkeley, Charleston, Colleton, Dorchester, Georgetown, Horry and Jasper. These eight counties comprise the coastal zone management region of the Ocean and Coastal Resource Management division of the S.C. Department of Health and Environmental Control The report examines the influence of these counties on the State's economy.Community/Rural/Urban Development,
The Impact of the Kansas Wheat Breeding Program on Wheat Yields, 1911–2006
This paper quantifies advances of the Kansas Agricultural Experiment Station (KAES) wheat breeding program for two time periods: (1) 1911 to 2006 and (2) 1977 to 2006. Using multiple regression, increases in yields of wheat varieties grown in Kansas are quantified, holding growing conditions and other improvements in productivity constant. Differences in KAES variety yields and those released by other public and private breeders are quantified. During the ‘‘new age’’ of wheat breeding (1977–2006), wheat breeding alone is found to have increased yields by 6.182 bushels per acre, or an average increase of 0.206 bushels per year.wheat yield, public wheat breeding, multiplicative heteroscedasticity, economic impact of technological change, Agribusiness, Farm Management, O13, Q16,
The rise of fully turbulent flow
Over a century of research into the origin of turbulence in wallbounded shear
flows has resulted in a puzzling picture in which turbulence appears in a
variety of different states competing with laminar background flow. At slightly
higher speeds the situation changes distinctly and the entire flow is
turbulent. Neither the origin of the different states encountered during
transition, nor their front dynamics, let alone the transformation to full
turbulence could be explained to date. Combining experiments, theory and
computer simulations here we uncover the bifurcation scenario organising the
route to fully turbulent pipe flow and explain the front dynamics of the
different states encountered in the process. Key to resolving this problem is
the interpretation of the flow as a bistable system with nonlinear propagation
(advection) of turbulent fronts. These findings bridge the gap between our
understanding of the onset of turbulence and fully turbulent flows.Comment: 31 pages, 9 figure
Are you really my clone? Identity verification of the in-trust sweetpotato collection at the International Potato Center.
The global in-trust sweetpotato collection maintained by the International Potato Center (CIP) in Lima, Peru consists of over 5,000 cultivated sweetpotato accessions maintained as clones in vitro as well as over 1,000 accessions from 67 species of Ipomoea maintained as seed populations. The clonal sweetpotato collection at CIP was initiated in the 1980’s and for 60% of the collection, original material still exists as potted plants in the greenhouse. This provides a unique opportunity where genetic integrity of a clonal collection, maintained in vitro for the past thirty years, can be confirmed by a side-by-side comparison of the same accession from the greenhouse. Initial molecular comparison is done using a set of twenty SSR primers followed by side-by-side comparison in the field using 30 morphological descriptors. Confirmation of identity requires both genetic and morphological analysis as a low percentage of the accessions appear to be duplicates based on SSR yet are morphologically distinct. Historical morphological descriptor data is used as a check to confirm identity and is being used as the sole check for accessions where we do not have original material for comparison. SSR results from 70% of the collection has confirmed that 85% of the in vitro accessions are true-to-type. In vitro accessions which are not true-to-type are reisolated and cleaned of viruses from the confirmed true-to-type greenhouse accessions. Accessions which are true-to-type are fingerprinted using DArTseq to provide a sequence-based fingerprint
Helicoidal instability of a scroll vortex in three-dimensional reaction-diffusion systems
We study the dynamics of scroll vortices in excitable reaction-diffusion
systems analytically and numerically. We demonstrate that intrinsic
three-dimensional instability of a straight scroll leads to the formation of
helicoidal structures. This behavior originates from the competition between
the scroll curvature and unstable core dynamics. We show that the obtained
instability persists even beyond the meander core instability of
two-dimensional spiral wave.Comment: 4 pages, 5 figures, revte
Scroll waves in isotropic excitable media : linear instabilities, bifurcations and restabilized states
Scroll waves are three-dimensional analogs of spiral waves. The linear
stability spectrum of untwisted and twisted scroll waves is computed for a
two-variable reaction-diffusion model of an excitable medium. Different bands
of modes are seen to be unstable in different regions of parameter space. The
corresponding bifurcations and bifurcated states are characterized by
performing direct numerical simulations. In addition, computations of the
adjoint linear stability operator eigenmodes are also performed and serve to
obtain a number of matrix elements characterizing the long-wavelength
deformations of scroll waves.Comment: 30 pages 16 figures, submitted to Phys. Rev.
Cognitive-behavioural therapy in medication-treated adults with attention-deficit/hyperactivity disorder and co-morbid psychopathology:a randomized controlled trial using multi-level analysis
Background. Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by high rates of co-morbid psychopathology. Randomized controlled trials of multimodal interventions, combining pharmacological and psychological treatments, have shown a robust treatment effect for ADHD symptoms but outcomes for co-morbid symptoms have been mixed. This may be accounted for by the type of intervention selected and/or by methodological problems including lack of follow-up and low power. The current study addressed these limitations in a parallel-group randomized controlled trial conducted in Iceland. Method. A total of 95 adult ADHD patients who were already being treated with medication (MED) were randomly assigned to receive treatment as usual (TAU/MED) or 15 sessions of cognitive-behavioural therapy (CBT/MED) using the R&R2ADHD intervention which employs both group and individual modalities. Primary measures of ADHD symptoms and severity of illness, and secondary measures of anxiety, depression and quality of life were given at baseline, end of treatment and 3-month follow-up. Primary outcomes were rated by clinicians blind to treatment condition assignment. Results. CBT/MED showed overall (combined outcome at end of treatment and 3-month follow-up) significantly greater reduction in primary outcomes for clinician-rated and self-rated ADHD symptoms. Treatment effect of primary outcomes was maintained at follow-up, which suggests robust and lasting findings. In contrast to the primary outcomes, the secondary outcomes showed significant improvement over time. Conclusions. The study provides evidence for the effectiveness of R&R2ADHD and demonstrates that there are differential effects over time for ADHD symptoms versus co-morbid problems, the latter taking longer to show positive effects
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