Double-beta decay Q values of 130Te, 128Te, and 120Te

The double-beta decay Q values of 130Te, 128Te, and 120Te have been determined from parent-daughter mass differences measured with the Canadian Penning Trap mass spectrometer. The 132Xe-129Xe mass difference, which is precisely known, was also determined to confirm the accuracy of these results. The 130Te Q value was found to be 2527.01(32) keV which is 3.3 keV lower than the 2003 Atomic Mass Evaluation recommended value, but in agreement with the most precise previous measurement. The uncertainty has been reduced by a factor of 6 and is now significantly smaller than the resolution achieved or foreseen in experimental searches for neutrinoless double-beta decay. The 128Te and 120Te Q values were found to be 865.87(131) keV and 1714.81(125) keV, respectively. For 120Te, this reduction in uncertainty of nearly a factor of 8 opens up the possibility of using this isotope for sensitive searches for neutrinoless double-electron capture and electron capture with positron emission.Comment: 5 pages, 2 figures, submitted to Physical Review Letter

Mass measurements near the rr-process path using the Canadian Penning Trap mass spectrometer

The masses of 40 neutron-rich nuclides from Z = 51 to 64 were measured at an average precision of $\delta m/m= 10^{-7}$ using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. The measurements, of fission fragments from a $^{252}$Cf spontaneous fission source in a helium gas catcher, approach the predicted path of the astrophysical $r$ process. Where overlap exists, this data set is largely consistent with previous measurements from Penning traps, storage rings, and reaction energetics, but large systematic deviations are apparent in $\beta$-endpoint measurements. Differences in mass excess from the 2003 Atomic Mass Evaluation of up to 400 keV are seen, as well as systematic disagreement with various mass models.Comment: 15 pages, 16 figures. v2 updated, published in Physical Review

Biologische bestrijding van bladluis in paprika: Evaluatie van nieuwe sluipwespen en gaasvliegen

Referaat Biologische bestrijding van bladluis in paprika is zeer lastig en kostbaar, waardoor de bestrijding in de gangbare teelt nog sterk leunt op inzet van insecticiden. De wens is om minder afhankelijk te zijn van deze middelen, omdat ze een risico vormen voor vervuiling van het oppervlaktewater en overschrijding van residu-eisen van supermarktketens. In paprika zijn de perzikluis Myzus persicae (groene en rode varianten) en boterbloemluis Aulacorthum solani de meest schadelijke bladluissoorten. In dit onderzoek zijn nieuwe sluipwespen en gaasvliegen beoordeeld als bestrijders van deze bladluissoorten. De bestrijding van rode perzikluis kon aanzienlijk verbeterd worden met de sluipwesp Aphidius matricariae. Het lijkt erop dat deze wespen actiever zijn in dichte bladluiskolonies. Inmiddels is deze soort op de markt gebracht en wordt hij volop ingezet bij paprikatelers. Voor boterbloemluis is deze wesp niet geschikt. Aphidius ervi is en blijft een effectieve sluipwesp voor de bestrijding van boterbloemluis. Voor de bestrijding van zowel boterbloemluis en perzikluis lijkt Aphidius gifuensis interessant. De waarde van deze sluipwesp moet nog verder beoordeeld worden op praktijkschaal. Bij de gaasvliegen bleken verschillende soorten zeer effectief bladluis te bestrijden in kooien, vooral soorten waarvan de volwassenen ook bladluis eten. Echter, bij loslatingen in kassen blijken de gaasvliegen zich maar nauwelijks of helemaal niet te vestigen. Voor de bestrijding van bladluishaarden met gaasvlieglarven lijkt de soort Chrysoperla lucasina een goede keuze te zijn. Abstract Biological control of aphids is one of the major challenges in sweet pepper. Most conventional growers still use insecticides to control aphids, but the market demands less residues. Also the risks of surface water pollution will force growers to switch to alternative control measures. The most damaging aphid species in sweet pepper are the peach aphid Myzus persicae and the foxglove aphid Aulacorthum solani. The aim of this research was to evaluate new parasitoids and lacewings, in order to enhance the biological control system of aphids in sweet pepper. In greenhouse trials we showed that Aphidius matricariae was more effective in controlling the peach aphid than the commonly used species Aphidius colemani. Control of the foxglove aphid was still most effectively done by the common species Aphidius ervi. The parasitoid Aphidius gifuensis is a promising candidate for biological control of both foxglove aphids and green peach aphids in sweet pepper, especially when these aphids occur together, but this species needs further evaluation in practice. Several lacewing species were very successful in controlling both aphid species in cage experiments, but none of them was able to establish in a larger crop. The control of aphids by lacewing larvae was most effectively done by the species Chrysoperla lucasina

Μελέτη και ανάπτυξη πλατφόρμας επεξεργαστή ανοικτού λογισμικού για την υλοποίηση μετεωρολογιακού δικτύου

This study aimed to gain insight into the microbial quality, safety and bacterial community composition of black soldier fly larvae (Hermetia illucens) reared at different facilities on a variety of organic waste streams. For seven rearing cycles, both on laboratory-scale and in large-scale facilities at several locations, the microbiota of the larvae was studied. Also samples of the substrate used and the residue (= leftover substrate after rearing, existing of non-consumed substrate, exuviae and faeces) were investigated. Depending on the sample, it was subjected to plate counting, Illumina Miseq sequencing and/or detection of specific food pathogens. The results revealed that the substrates applied at the various locations differed substantially in microbial numbers as well as in the bacterial community composition. Furthermore, little similarity was observed between the microbiota of the substrate and that of the larvae reared on that substrate. Despite substantial differences between the microbiota of larvae reared at several locations, 48 species-level operational taxonomic units (OTUs) were shared by all larvae, among which most belonged to the phyla Firmicutes and Proteobacteria. Although the substrate is assumed to be an important source of bacteria, our results suggest that a variety of supposedly interacting factors-both abiotic and biotic-are likely to affect the microbiota in the larvae. In some larvae and/or residue samples, potential foodborne pathogens such as Salmonella and Bacillus cereus were detected, emphasising that decontamination technologies are required when the larvae are used in feed, just as for other feed ingredients, or eventually in food

Studies of neutron-rich nuclei using the CPT mass spectrometer at CARIBU

The nucleosynthetic path of the astrophysical r-process and the resulting elemental abundances depend on neutron-separation energies which can be determined from the masses of the nuclei along the r-process reaction path. Due to the current lack of experimental data, mass models are often used. The mass values provided by the mass models are often too imprecise or disagree with each other. Therefore, direct high-precision mass measurements of neutron-rich nuclei are necessary to provide input parameters to the calculations and help refine the mass models. The Californium Rare Isotope Breeder Upgrade (CARIBU) facility of Argonne National Laboratory will provide experiments with beams of short-lived neutron-rich nuclei. The Canadian Penning Trap (CPT) mass spectrometer has been relocated to the CARIBU low-energy beam line to extend measurements of the neutron-rich nuclei into the mostly unexplored region along the r-process path. This will allow precise mass measurements (∼ 10 keV/c2) of more than a hundred very neutron-rich isotopes that have not previously been measured

Dynein activating adaptor BICD2 controls radial migration of upper-layer cortical neurons in vivo

For the proper organization of the six-layered mammalian neocortex it is required that neurons migrate radially from their place of birth towards their designated destination. The molecular machinery underlying this neuronal migration is still poorly understood. The dynein-adaptor protein BICD2 is associated with a spectrum of human neurologi

Tensor interaction limit derived from the α-β-ν̄ correlation in trapped Li8 ions

A measurement of the α-β-ν̄ angular correlation in the Gamow-Teller decay Li8→Be*8+ν̄+β, Be*8→ α+α has been performed using ions confined in a linear Paul trap surrounded by silicon detectors. The energy difference spectrum of the α particles emitted along and opposite the direction of the β particle is consistent with the standard model prediction and places a limit of 3.1% (95.5% confidence level) on any tensor contribution to the decay. From this result, the amplitude of any tensor component CT relative to that of the dominant axial-vector component CA of the electroweak interaction is limited to |CT/CA|\u3c0.18 (95.5% confidence level). This experimental approach is facilitated by several favorable features of the Li8 β decay and has different systematic effects than the previous β-ν̄ correlation results for a pure Gamow-Teller transition obtained from studying He6 β decay. © 2013 American Physical Society

β-delayed neutron spectroscopy using trapped radioactive ions

A novel technique for β-delayed neutron spectroscopy has been demonstrated using trapped ions. The neutron-energy spectrum is reconstructed by measuring the time of flight of the nuclear recoil following neutron emission, thereby avoiding all the challenges associated with neutron detection, such as backgrounds from scattered neutrons and γ rays and complicated detector-response functions. I+137 ions delivered from a Cf252 source were confined in a linear Paul trap surrounded by radiation detectors, and the β-delayed neutron-energy spectrum and branching ratio were determined by detecting the β- and recoil ions in coincidence. Systematic effects were explored by determining the branching ratio three ways. Improvements to achieve higher detection efficiency, better energy resolution, and a lower neutron-energy threshold are proposed. © 2013 American Physical Society