A dual isotopic approach using radioactive phosphorus and the isotopic composition of oxygen associated to phosphorus to understand plant reaction to a change in P nutrition

Abstract Background Changing the phosphorus (P) nutrition leads to changes in plant metabolism. The aim of this study was to investigate how these changes are reflected in the distribution of 33P and the isotopic composition of oxygen associated to P (δ18OP) in different plant parts of soybean (Glycine max cv. Toliman). Two P pools were extracted sequentially with 0.3 M trichloroacetic acid (TCA P) and 10 M nitric acid (HNO3; residual P). Results The δ18OP of TCA P in the old leaves of the − P plants (23.8‰) significantly decreased compared to the + P plants (27.4‰). The 33P data point to an enhanced mobilisation of P from residual P in the old leaves of the − P plants compared to the + P plants. Conclusions Omitting P for 10 days lead to a translocation of P from source to sink organs in soybeans. This was accompanied by a significant lowering of the δ18OP of TCA P in the source organs due to the enzymatic hydrolysis of organic P. Combining 33P and δ18OP can provide useful insights in plant responses to P omission at an early stage

ESC Supernova spectroscopy of non-ESC targets

We present the spectra of 36 Supernovae (SNe) of various types, obtained by the European Supernova Collaboration. Because of the spectral classification and the phase determination at their discovery the SNe did not warrant further study, and the spectra we present are the only available for the respective objects. In this paper we present and discuss this material using a new software for the automated classification of SNe spectra. As a validation of the software, we verify the classification and phase estimate reported for these objects in their discovery / classification circulars. For the comparison, the software uses the library of template spectra of Padova-Asiago Supernova Archive (ASA). For each spectrum of our sample we present a brief, individual discussion, highlighting the main characteristics and possible peculiarities. The comparison with ASA spectra confirms the previous classification of all objects and refines the age estimates. For our software we determine numerical limits of "safe" spectral classification and the uncertainties of the phase determination.Comment: 22 pages, accepted for publication in A&

Micro-Electro-Mechanical-Systems (MEMS) and Fluid Flows

The micromachining technology that emerged in the late 1980s can provide micron-sized sensors and actuators. These micro transducers are able to be integrated with signal conditioning and processing circuitry to form micro-electro-mechanical-systems (MEMS) that can perform real-time distributed control. This capability opens up a new territory for flow control research. On the other hand, surface effects dominate the fluid flowing through these miniature mechanical devices because of the large surface-to-volume ratio in micron-scale configurations. We need to reexamine the surface forces in the momentum equation. Owing to their smallness, gas flows experience large Knudsen numbers, and therefore boundary conditions need to be modified. Besides being an enabling technology, MEMS also provide many challenges for fundamental flow-science research

Genome\u2011wide diversity and runs of homozygosity in the \u201cBraque Fran\ue7ais, type Pyr\ue9n\ue9es\u201d dog breed

Objective: Braque Fran\uc3\ua7ais, type Pyr\uc3\ua9n\uc3\ua9es is a French hunting-dog breed whose origin is traced back to old pointing gun-dogs used to assist hunters in finding and retrieving game. This breed is popular in France, but seldom seen elsewhere. Despite the ancient background, the literature on its genetic characterization is surprisingly scarce. A recent study looked into the demography and inbreeding using pedigree records, but there is yet no report on the use of molecular markers in this breed. The aim of this work was to genotype a population of Braque Fran\uc3\ua7ais, type Pyr\uc3\ua9n\uc3\ua9es dogs with the high-density SNP array to study the genomic diversity of the breed. Results: The average observed (HO) and expected (HE) heterozygosity were 0.371 (\uc2\ub1 0.142) and 0.359 (\uc2\ub1 0.124). Effective population size (NE) was 27.5635 runs of homozygosity (ROH) were identified with average length of 2.16 MB. A ROH shared by 75% of the dogs was detected at the beginning of chromosome 22. Inbreeding coefficients from marker genotypes were in the range FIS= [- 0.127, 0.172]. Inbreeding estimated from ROH (FROH) had mean 0.112 (\uc2\ub1 0.023), with range [0.0526, 0.225]. These results show that the Braque Fran\uc3\ua7ais, type Pyr\uc3\ua9n\uc3\ua9es breed is a relatively inbred population, but with still sufficient genetic variability for conservation and genetic improvement

Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment

The Double Chooz Experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. A ratio of 0.944 $\pm$ 0.016 (stat) $\pm$ 0.040 (syst) observed to predicted events was obtained in 101 days of running at the Chooz Nuclear Power Plant in France, with two 4.25 GW$_{th}$ reactors. The results were obtained from a single 10 m$^3$ fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 measurement as an anchor point. The deficit can be interpreted as an indication of a non-zero value of the still unmeasured neutrino mixing parameter \sang. Analyzing both the rate of the prompt positrons and their energy spectrum we find \sang = 0.086 $\pm$ 0.041 (stat) $\pm$ 0.030 (syst), or, at 90% CL, 0.015 $<$ \sang $\ <$ 0.16.Comment: 7 pages, 4 figures, (new version after PRL referee's comments

Analysis of the Maize dicer-like1 Mutant, fuzzy tassel, Implicates MicroRNAs in Anther Maturation and Dehiscence

Sexual reproduction in plants requires development of haploid gametophytes from somatic tissues. Pollen is the male gametophyte and develops within the stamen; defects in the somatic tissues of the stamen and in the male gametophyte itself can result in male sterility. The maize fuzzy tassel (fzt) mutant has a mutation in dicer-like1 (dcl1), which encodes a key enzyme required for microRNA (miRNA) biogenesis. Many miRNAs are reduced in fzt, and fzt mutants exhibit a broad range of developmental defects, including male sterility. To gain further insight into the roles of miRNAs in maize stamen development, we conducted a detailed analysis of the male sterility defects in fzt mutants. Early development was normal in fzt mutant anthers, however fzt anthers arrested in late stages of anther maturation and did not dehisce. A minority of locules in fzt anthers also exhibited anther wall defects. At maturity, very little pollen in fzt anthers was viable or able to germinate. Normal pollen is tricellular at maturity; pollen from fzt anthers included a mixture of unicellular, bicellular, and tricellular pollen. Pollen from normal anthers is loaded with starch before dehiscence, however pollen from fzt anthers failed to accumulate starch. Our results indicate an absolute requirement for miRNAs in the final stages of anther and pollen maturation in maize. Anther wall defects also suggest that miRNAs have key roles earlier in anther development. We discuss candidate miRNAs and pathways that might underlie fzt anther defects, and also note that male sterility in fzt resembles water deficit-induced male sterility, highlighting a possible link between development and stress responses in plants.ECU Open Access Publishing Support Fun

Precision muon reconstruction in Double Chooz

We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of the liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going muon intersecting the center of the detector, the resolution is ~40mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz. © 2014 Elsevier B.V