Production of Minitubers from Potato Seedlings and Advanced Selections

This cooperation between the University of Maine and USDA-ARS was aimed at providing the infrastructure and manpower support for the propagation and advancement of tetraploid potato breeding materials for the USDFA-ARS-Beltsville Potato Breeding Program (K. Haynes, PI)

Electrophoretic variation of isozymes in plumules of rice (Oryza saliva L.) - a key to the identification of 76 alleles at 24 loci

A simple and efficient method has been developed for studying isozyme variation in rice. It involves starch gel electrophoresis of crude rice plumule extracts, followed by staining of 13 enzymes. It permits monitoring the variation at 24 polymorphic loci distributed on at least 8 chromosomes. Technical procedures are described, and the zymograms obtained from materials containing all known alleles are shown. A total of 76 alleles can be readily identified

Cell Size Checkpoint Control by the Retinoblastoma Tumor Suppressor Pathway

Size control is essential for all proliferating cells, and is thought to be regulated by checkpoints that couple cell size to cell cycle progression. The aberrant cell-size phenotypes caused by mutations in the retinoblastoma (RB) tumor suppressor pathway are consistent with a role in size checkpoint control, but indirect effects on size caused by altered cell cycle kinetics are difficult to rule out. The multiple fission cell cycle of the unicellular alga Chlamydomonas reinhardtii uncouples growth from division, allowing direct assessment of the relationship between size phenotypes and checkpoint function. Mutations in the C. reinhardtii RB homolog encoded by MAT3 cause supernumerous cell divisions and small cells, suggesting a role for MAT3 in size control. We identified suppressors of an mat3 null allele that had recessive mutations in DP1 or dominant mutations in E2F1, loci encoding homologs of a heterodimeric transcription factor that is targeted by RB-related proteins. Significantly, we determined that the dp1 and e2f1 phenotypes were caused by defects in size checkpoint control and were not due to a lengthened cell cycle. Despite their cell division defects, mat3, dp1, and e2f1 mutants showed almost no changes in periodic transcription of genes induced during S phase and mitosis, many of which are conserved targets of the RB pathway. Conversely, we found that regulation of cell size was unaffected when S phase and mitotic transcription were inhibited. Our data provide direct evidence that the RB pathway mediates cell size checkpoint control and suggest that such control is not directly coupled to the magnitude of periodic cell cycle transcription

Experimental study of honeycomb SiCSi under highly concentrated solar flux: Evolution of its thermo-radiative properties

The material that is used in solar receivers is subjected to intense cyclic thermal stresses and extreme temperatures, which are directly dependent on the intermittence of the solar resource. These factors accelerate the ageing mechanisms and reduce the durability of the receivers because of a reduction of their thermal performance. This study presents guidelines to study the thermo-radiative properties of an absorber material that is subjected to a highly concentrated solar flux. The material was a square honeycomb SiCSi structure that is typically used in volumetric air receivers. Accelerated ageing tests were performed by means of crashing thermal treatments, in which the modulus and period of the incident flux and the boundary conditions of the material were varied. The reflectivity and absorptivity of the material were experimentally characterized before and after the thermal treatments. The measurements were performed using two different reflectometers, one monochromatic and one in the solar band; the latter can measure at ambient temperature or high temperature that is representative of the operational conditions (400-700 degrees C). However, only the solar band reflectometer working at high temperature was able to detect the evolution of the thermo-radiative properties of the material, which highlights the important role of the temperature and the wavelength. Furthermore, the thermal treatments in which the samples were water-cooled and in which the solar flux was medial more quickly accelerated the ageing mechanism of the material and reduced its absorptivity.The authors acknowledge the financial support of the research programme of the Universidad Carlos III de Madrid, 2015, which made this study possible through a mobility grant. Moreover, this work was supported by the French "Investments for the future" programme, which is managed by the National Agency for Research under contract ANR-10-LABX-22-01 by Labex SOLSTICE and by the Spanish government under the project ENE2012-34255

Development of a new method to estimate the incident solar flux on central receivers from deteriorated heliostats

This work proposes a new empirical direct methodology to estimate both the solar flux distribution and intensity on the surface of central receivers. In solar power tower plants with deteriorated heliostats, the numerical simulations to estimate the incident solar flux are not precise. Hence the thermal behaviour of the receivers cannot be determined. In those cases, direct measurement or semi-empirical methodologies are required to characterize the radiant power on the receiver. The new methodology proposed, named "Superposition method", consists in the hourly characterization of the reflected solar beam of each individual heliostat by means of a pyrheliometer, a passive screen, a flux sensor, a camera and digital image analysis. According to the aiming strategy used during receiver operation, each individual solar flux distribution and intensity can be gathered to obtain the total incident radiant power on the solar receiver. This non-real-time method has the advantage of reproducing any solar flux distribution on the receiver at present and past time

Improvement of multilateration(MLAT) accuracy and convergence for airport surveillance

AbstractIn this paper, westudy, evaluate and develop the use of regularization methods to solve the location problem in multilateration systems using Mode-S signals. The Tikhonov method has been implemented as a first applicationto solve the classical system of hyperbolic equations in multilateration systems. Some simulations are obtained and the results are compared with those obtained by the well established Taylor linearization and with the Cramér-Rao Lower Bound analysis. Significant improvements are found for the applicationof Tikhonov method

Effect of an α-Tocopherol-Containing Antioxidant Parenteral Emulsion upon Gut Microbiota in Preterm Infants

Preterm babies are born with an immature intestine and are at higher risk for intestinal failure and needing for parenteral nutrition than full-term newborns. These babies show an altered intestinal microbiota, which may results of key importance for later health. However, there is a lack of information on effect of parenteral formulas upon the establishing infant microbiota. Moreover, the microbiota alterations present in preterm newborns have been related with an altered redox-potential which hinders the establishment of strict anaerobes. Thus, interventions aimed at reducing the oxidative stress in these infants, including those under parenteral nutrition, could also affect the intestinal microbiota composition. We assessed the effect upon the gut microbiota of the administration during 30 days of a lipid emulsion, containing ω3 polyunsaturated fatty acids and α-tocopherol, or a control emulsion containing soybean-bases lipids to parenterally-fed preterm newborns. In spite of its high antioxidant potential, the infants receiving the experimental fat emulsion showed a trend to increase of facultative anaerobes such as enterobacteria and specifically of Klebsiella. This study stresses the need of further work monitoring the impact of early-life parenteral nutrition on the establishment of the intestinal microbiota