3,576 research outputs found
Molecular and Genetic Regulation of Sensory Quality of Climacteric Fruit
The sensory quality of fruit has become a major criterion in making the
purchasing decision by consumers. Breeding programs have mainly been directed,
from the post-harvest stand point, towards improving shelf-life. Chance seedlings or
mutants with improved agronomic traits and/or extended shelf-life have been used
for introgressing the long shelf-life character and eventually improved sensory
quality traits in commercial genotypes of apple, melon or tomato. Because the plant
hormone ethylene plays a central role in both storability and ripening of climacteric
fruit, the generation by biotechnology of ethylene-inhibited fruit has offered a
powerful tool to better understand, at the molecular and genetic level, the interrelations
between storability and sensory quality. In the melon, inhibition of ethylene
synthesis results is a strong inhibition of the synthesis of aroma volatiles while the
accumulation of sugars is not affected or is even improved. The softening of the flesh
is strongly affected but not abolished. Mid or long shelf-life melons generated by
classical breeding present the same behavior. The generation of recombinant inbred
lines by crossing a typical climacteric melon (Cantaloupe Charentais of the
cantalupensis group) with a non climacteric melon (PI161375 of the agrestis
chinensis group) allowed to demonstrate that the climacteric character is conferred
by 2 duplicated loci only, which are of great importance for the regulation of
storability and sensory quality. Due to the importance of aroma volatiles in sensory
quality and to the strong negative correlation between aroma production and
ethylene synthesis, we have developed a research program aimed at isolating genes
involved in the synthesis of aroma volatiles. We will report on the recent advances in
the field with special emphasis on the characterization of genes responsible for the
synthesis of esters, a family of compounds crucial for the flavor of many fruit
SUE: A Special Purpose Computer for Spin Glass Models
The use of last generation Programmable Electronic Components makes possible
the construction of very powerful and competitive special purpose computers. We
have designed, constructed and tested a three-dimensional Spin Glass model
dedicated machine, which consists of 12 identical boards. Each single board can
simulate 8 different systems, updating all the systems at every clock cycle.
The update speed of the whole machine is 217ps/spin with 48 MHz clock
frequency. A device devoted to fast random number generation has been developed
and included in every board. The on-board reprogrammability permits us to
change easily the lattice size, or even the update algorithm or the action. We
present here a detailed description of the machine and the first runs using the
Heat Bath algorithm.Comment: Submitted to Computer Physics Communications, 19 pages, 5 figures,
references adde
Appellation of Origin Status and Economic Development: A Case Study of the Mezcal Industry
Mezcal is an alcoholic beverage produced only in selected regions of Mexico under appellation of origin status from the Word Intellectual Property Organization. While it has been produced in Mexico for many centuries, mezcal’s appellation of origin was only granted in 1995. Therefore efforts to produce and market it as a premium product have a relatively short history. This case study examines developments in the production and marketing of this unique product, and the activities of the marketing cooperative El Tecuán in Guerrero State in this process.mezcal, Mexico, appellation, marketing, cooperative, Community/Rural/Urban Development, Marketing,
Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate?
Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios
The Gould's Belt Very Large Array Survey II: The Serpens region
We present deep (Jy) radio continuum observations of the Serpens
molecular cloud, the Serpens south cluster, and the W40 region obtained using
the Very Large Array in its A configuration. We detect a total of 146 sources,
29 of which are young stellar objects (YSOs), 2 are BV stars and 5 more are
associated with phenomena related to YSOs. Based on their radio variability and
spectral index, we propose that about 16 of the remaining 110 unclassified
sources are also YSOs. For approximately 65% of the known YSOs detected here as
radio sources, the emission is most likely non-thermal, and related to stellar
coronal activity. As also recently observed in Ophiuchus, our sample of YSOs
with X-ray counterparts lies below the fiducial G\"udel & Benz relation.
Finally, we analyze the proper motions of 9 sources in the W40 region. This
allows us to better constrain the membership of the radio sources in the
region.Comment: Accepted in The Astrophysical Journa
Risk assessment and mapping of extreme floods in non-dyked communities along the Elbe and Mulde Rivers
International audienceAssessing and mapping damage risk of floods for large river basins is still in its infancy. Damage risk is understood to be the combination of flood hazard and the vulnerability of communities to a flood of a particular return period. Risk is calculated and mapped for two communities in which dykes are not located for flood protection: Meissen on the Elbe River and Döbeln in the Mulde catchment. Different methodologies for the computation of flood depth and inundation extent of varying flood return periods (hazard) are compared. Exposure and relative damage to the flooding (vulnerability) based on land-use coverages of different scale are also compared and discussed. A property asset coverage completes the data requirements for the construction of the risk maps. Recommendations for continued research on risk assessments of large river basins conclude the study
A rotating molecular jet from a Perseus protostar
We present CO(2-1) line and 1.4 mm continuum archival observations,
made with the Submillimeter Array, of the outflow HH 797 located in the IC 348
cluster in Perseus. The continuum emission is associated with a circumstellar
disk surrounding the class 0 object IC 348-MMS/SMM2, a very young solar analog.
The line emission, on the other hand, delineates a collimated outflow, and
reveals velocity asymmetries about the flow axis over the entire length of the
flow. The amplitude of velocity differences is of order 2 km s over
distances of about 1000 AU, and we interpret them as evidence for jet rotation
--although we also discuss alternative possibilities. A comparison with
theoretical models suggests that the magnetic field lines threading the
protostellar jet might be anchored to the disk of a radius of about 20 AU.Comment: Accepted for publication in Ap
The Gould's Belt Very Large Array Survey III. The Orion region
We present results from a high-sensitivity (60 Jy), large-scale (2.26
square degree) survey obtained with the Karl G. Jansky Very Large Array as part
of the Gould's Belt Survey program. We detected 374 and 354 sources at 4.5 and
7.5 GHz, respectively. Of these, 148 are associated with previously known Young
Stellar Objects (YSOs). Another 86 sources previously unclassified at either
optical or infrared wavelengths exhibit radio properties that are consistent
with those of young stars. The overall properties of our sources at radio
wavelengths such as their variability and radio to X-ray luminosity relation
are consistent with previous results from the Gould's Belt Survey. Our
detections provide target lists for followup VLBA radio observations to
determine their distances as YSOs are located in regions of high nebulosity and
extinction, making it difficult to measure optical parallaxes.Comment: Accepted for publication in ApJ; 51 pages, 15 figures, 5 table
The U(1)-Higgs Model: Critical Behaviour in the Confinig-Higgs region
We study numerically the critical properties of the U(1)-Higgs lattice model,
with fixed Higgs modulus, in the region of small gauge coupling where the Higgs
and Confining phases merge. We find evidence of a first order transition line
that ends in a second order point. By means of a rotation in parameter space we
introduce thermodynamic magnitudes and critical exponents in close resemblance
with simple models that show analogous critical behaviour. The measured data
allow us to fit the critical exponents finding values in agreement with the
mean field prediction. The location of the critical point and the slope of the
first order line are accurately given.Comment: 21 text pages. 12 postscript figures available on reques
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