The algebro-geometric initial value problem for the Ablowitz-Ladik hierarchy

We discuss the algebro-geometric initial value problem for the Ablowitz-Ladik hierarchy with complex-valued initial data and prove unique solvability globally in time for a set of initial (Dirichlet divisor) data of full measure. To this effect we develop a new algorithm for constructing stationary complex-valued algebro-geometric solutions of the Ablowitz-Ladik hierarchy, which is of independent interest as it solves the inverse algebro-geometric spectral problem for general (non-unitary) Ablowitz-Ladik Lax operators, starting from a suitably chosen set of initial divisors of full measure. Combined with an appropriate first-order system of differential equations with respect to time (a substitute for the well-known Dubrovin-type equations), this yields the construction of global algebro-geometric solutions of the time-dependent Ablowitz-Ladik hierarchy. The treatment of general (non-unitary) Lax operators associated with general coefficients for the Ablowitz-Ladik hierarchy poses a variety of difficulties that, to the best of our knowledge, are successfully overcome here for the first time. Our approach is not confined to the Ablowitz-Ladik hierarchy but applies generally to (1+1)-dimensional completely integrable soliton equations of differential-difference type.Comment: 47 page

Observations of vertical velocity power spectra with the SOUSY VHF radar

A data set taken with the SOUSY VHF radar from October 28 to November 13, 1981 was used to calculate the power spectrum of the vertical velocities directly from the vertical beam measurements. The spectral slopes for the frequency spectra have been determined out to periods of several days and have been found to have values near -1 in the troposphere and shallower slopes in the lower stratosphere. The value of -1 is in agreement with the value found by Larsen et al. (1985) and Balsley and Carter (1982) in the range from a few minutes to 1 hr

Mechanisms of interpersonal sway synchrony and stability

Here we explain the neural and mechanical mechanisms responsible for synchronizing sway and improving postural control during physical contact with another standing person. Postural control processes were modelled using an inverted pendulum under continuous feedback control. Interpersonal interactions were simulated either by coupling the sensory feedback loops or by physically coupling the pendulums with a damped spring. These simulations precisely recreated the timing and magnitude of sway interactions observed empirically. Effects of firmly grasping another person's shoulder were explained entirely by the mechanical linkage. This contrasted with light touch and/or visual contact, which were explained by a sensory weighting phenomenon; each person's estimate of upright was based on a weighted combination of veridical sensory feedback combined with a small contribution from their partner. Under these circumstances, the model predicted reductions in sway even without the need to distinguish between self and partner motion. Our findings explain the seemingly paradoxical observation that touching a swaying person can improve postural control.This work was supported by two BBSRC grants (BB/100579X/1 and an Industry Interchange Award)

Multiple origins of the i heterokaryon gene in Rockefeller-Lindegren strains

The Fungal Genetics Stock Center has been able to revive four old lyophilized cultures of the mutants used by Garnjobst in her pioneering 1953 study of vegetative incompatibility in Neurospora crassa. One of them, inositolless (37401), tests as het-c,* het-d, het-E, as described by Garnjobst. This strain cannot be tested completely for het-I/i, but it is not het-I/i compatible with the FGSC riboflavinless het-cdE I tester strain. The other early cultures were the standard Rockefeller-Lindegren het-CDEI. A lineage chart of the het-e strains in the Wilson-Garnjobst heterokaryon testers shows that many of the inl testers are het-i, which probably accounts for the erratic performance observed in growth tubes with these testers. A list of het-I/i genotypes of 31 FGSC strains is included

Genetic diversity at the FMR1 locus in the Indonesian population

We report an analysis of allelic diversity at short tandem repeat polymorphisms within the fragile XA locus in 1069 male volunteers from twelve Indonesian sub-populations. An odd numbered allele of DXS548 was found at high frequency in all Indonesian populations. Greater allelic diversity was identified at the loci under study than has been previously reported for an Asian population. These differences distinguish the Indonesian population from all previously reported Asian, European and African populations. A high frequency of small premutation alleles, 4/120 (3.3%, 95% CI 0.9–8.3%), was identified in the Moluccan population of Hiri Island

UHF and VHF radar observations of thunderstorms

A study of thunderstorms was made in the Summer of 1985 with the 430-MHz and 50-MHz radars at the Arecibo Observatory in Puerto Rico. Both radars use the 300-meter dish, which gives a beam width of less than 2 degrees even at these long wavelengths. Though the radars are steerable, only vertical beams were used in this experiment. The height resolution was 300 and 150 meters for the UHF and VHF, respectively. Lightning echoes, as well as returns from precipitation and clear-air turbulence were detected with both wavelengths. Large increases in the returned power were found to be coincident with increasing downward vertical velocities at UHF, whereas at VHF the total power returned was relatively constant during the life of a storm. This was attributed to the fact that the VHF is more sensitive to scattering from the turbulence-induced inhomogeneities in the refractive index and less sensitive to scatter from precipitation particles. On occasion, the shape of the Doppler spectra was observed to change with the occurrence of a lightning discharge in the pulse volume. Though the total power and mean reflectivity weighted Doppler velocity changed little during these events, the power is Doppler frequency bins near that corresponding to the updraft did increase substantially within a fraction of a second after a discharge was detected in the beam. This suggests some interaction between precipitation and lightning

Transparent soil for imaging the rhizosphere

Understanding of soil processes is essential for addressing the global issues of food security, disease transmission and climate change. However, techniques for observing soil biology are lacking. We present a heterogeneous, porous, transparent substrate for in situ 3D imaging of living plants and root-associated microorganisms using particles of the transparent polymer, Nafion, and a solution with matching optical properties. Minerals and fluorescent dyes were adsorbed onto the Nafion particles for nutrient supply and imaging of pore size and geometry. Plant growth in transparent soil was similar to that in soil. We imaged colonization of lettuce roots by the human bacterial pathogen Escherichia coli O157:H7 showing micro-colony development. Micro-colonies may contribute to bacterial survival in soil. Transparent soil has applications in root biology, crop genetics and soil microbiology

Peatlands and the carbon cycle: from local processes to global implications - a synthesis

Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15-30% of the world's soil carbon ( C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change. The main drivers controlling most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange ( NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors. Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales

Comparison of Grain Sources (Barley, White Corn, and Yellow Corn) for Swine Diets and Their Effects on Meat Quality and Production Traits

Efficient pork production is a necessity for an economically viable swine industry. Number two yellow corn is considered the primary energy source for swine diets in the Midwest. Despite the low protein content, corn is considered one of the most economical feed stuffs available to the swine production system. Barley is a high fiber that has approximately 89% of the energy content of corn. While barley contains a higher protein and amino acid level than corn, animal performance is expected to be depressed due to the high fiber content. Because barley lacks the carotene content that yellow corn possesses, it has been hypothesized that barley-fed pigs will yield higher meat and fat quality that is desired by export markets. White corn was used in this trial to determine its contribution to meat quality and growth traits. An experiment was conducted to evaluate the effect of energy source on performance and carcass traits of pigs. Diet treatments (primary energy source) were: 1) yellow corn, 2) white corn, 3) 1/3 yellow corn, 2/3 white corn, 4) 2/3 yellow corn, 1/3 white corn, 5) barley. Pigs completing the trial were from two sires lines, Duroc (n=500) and Hamp x Duroc (n=499), that were mated to PIC 1055 females. Pigs were randomly allocated to pens based on genetic type and gender using a 2 x 2 x 5 factorial arrangement with two genetic types, two sexes (barrows and gilts) and five treatments. Animals fed these diets differing in energy source did not express a difference in average daily gain, average daily feed intake, feed-to-gain ratio, backfat depth or percent fat free lean. However, barley-fed pigs did have a smaller (p \u3c .05) loin muscle area than pigs fed corn-based diets. Diet did not have an effect on sensory panel traits for tenderness or chewiness and limited differences were observed for juiciness, flavor, and off-flavor. Percentage loin purge, and cooking loss did not differ among diets fed to the pigs with minimal difference noted for color values. Pigs fed barley diets did have lower iodine value content within the subcutaneous fat indicating that the fat is of firmer quality. Results of this trial suggest that barley does not have an advantage in meat quality traits when compared to traditional corn-based diets. Barley does however have a significant impact on the hardness of pork fat, but does not have a significant effect on subjective color values