Influence of previous crops and nematicide treatments on root lesion nematode populations and crop yields

Nous avons étudié au champ l'influence du précédent cultural, de la séquence culturelle et de traitements à l'aldicarbe sur les populations de nematodes des nodosités et sur les rendements de diverses cultures à l'île-du Prince-Édouard. La culture précédente a eu le plus grand impact sur le nombre de nematodes. Les séquences des cultures ont parfois eu une influence sur les populations de nematodes des nodosités (principalement Pratylenchus penetrans) et sur les rendements. Dans les champs commerciaux d'orge (Hordeum vulgare), les nematodes des nodosités étaient plus nombreux lorsque l'orge suivait une culture combinée de trèfle rouge (Trifolium pratense) et de fléole (Phleum pratense) et les nematodes du rabougrissement (Tylenchorynchus spp., principalement T. dubiuset Merlinius spp.) étaient plus nombreux quand l'orge était semée pendant deux années consécutives. La masse de la matière sèche combinée du feuillage et du grain était plus importante lorsque l'orge était semée auprès des pommes de terre (Solanum tuberosum) et cette masse était plus faible avec deux cultures successives d’orge ou avec un mélange de trèfle rouge et de fléole. En conditions expérimentales au champ, les populations de nématodes des nodosités étaient plus élevées dans les racines d’orge lorsque celle-ci était cultivée après des pommes de terre et les rendements en grain étaient plus faibles lorsque l’orge était cultivée pendant deux années consécutives. Les changements dans les populations de nématodes chez la pomme de terre n’étaient pas associés aux séquences débutant avec le blé (Triticum aestivum) ou l’orge que dans les séquences débutant avec les pommes de terre ou le soya (Glycine max). L’aldicarbe a réduit le nombre de nématodes des nodosités en plus d’accroître les rendements en pommes de terre et en soya.A field study assessing the influence of the previous crop, the crop sequence, and aldicarb treatments on root lesion nematode populations and crop yields was carried out in Prince-Edward-Island, Canada. The most recent crop had the greatest impact on nematode numbers. The crop sequences had an influence in some cases on root lesion nematode populations (primarily Pratylenchus penetrans) and on crop yields. In commercial barley (Hordeum vulgare) fields, root lesion nematodes in roots were greatest when barley followed a red clover (Trifolium pratense) timothy (Phleum pratense) ley, and stunt nematodes (Tylenchorhynchus spp., primarily T. dubius, and Merlinius spp.) were more common when barley followed barley. The combined dry weight of foliage and grain was larger when barley was planted after potato (Solanumtuberosum) and smaller when barley followed barley or a red clover-timothy mixture. Under experimental field conditions, root lesion nematode populations were largest in barley roots when barley followed potato and grain yields were smallest when barley followed barley. Changes in nematode populations in potato were not associated with crop sequences. Potato tuber yields were higher in the sequences that began with wheat (Triticum aestivum) or barley than in the sequences that began with potato or soybean (Glycine max). Aldicarb reduced the numbers of root lesion nematodes in roots with concomitant yield increases in potato and soybean

Chiral three-nucleon forces and bound excited states in neutron-rich oxygen isotopes

We study the spectra of neutron-rich oxygen isotopes based on chiral two- and three-nucleon interactions. First, we benchmark our many-body approach by comparing ground-state energies to coupled-cluster results for the same two-nucleon interaction, with overall good agreement. We then calculate bound excited states in 21,22,23O, focusing on the role of three-nucleon forces, in the standard sd shell and an extended sdf7/2p3/2 valence space. Chiral three-nucleon forces provide important one- and two-body contributions between valence neutrons. We find that both these contributions and an extended valence space are necessary to reproduce key signatures of novel shell evolution, such as the N = 14 magic number and the low-lying states in 21O and 23O, which are too compressed with two-nucleon interactions only. For the extended space calculations, this presents first work based on nuclear forces without adjustments. Future work is needed and open questions are discussed.Comment: 6 pages, 4 figures, published versio

Treatment-limiting renal tubulopathy in patients treated with tenofovir disoproxil fumarate.

OBJECTIVES: Tenofovir disoproxil fumarate (TDF) is widely used in the treatment or prevention of HIV and hepatitis B infection. TDF may cause renal tubulopathy in a small proportion of recipients. We aimed to study the risk factors for developing severe renal tubulopathy. METHODS: We conducted an observational cohort study with retrospective identification of cases of treatment-limiting tubulopathy during TDF exposure. We used multivariate Poisson regression analysis to identify risk factors for tubulopathy, and mixed effects models to analyse adjusted estimated glomerular filtration rate (eGFR) slopes. RESULTS: Between October 2002 and June 2013, 60 (0.4%) of 15,983 patients who had received TDF developed tubulopathy after a median exposure of 44.1 (IQR 20.4, 64.4) months. Tubulopathy cases were predominantly male (92%), of white ethnicity (93%), and exposed to antiretroviral regimens that contained boosted protease inhibitors (PI, 90%). In multivariate analysis, age, ethnicity, CD4 cell count and use of didanosine or PI were significantly associated with tubulopathy. Tubulopathy cases experienced significantly greater eGFR decline while receiving TDF than the comparator group (-6.60 [-7.70, -5.50] vs. -0.34 [-0.43, -0.26] mL/min/1.73 m2/year, p < 0.0001). CONCLUSIONS: Older age, white ethnicity, immunodeficiency and co-administration of ddI and PI were risk factors for tubulopathy in patients who received TDF-containing antiretroviral therapy. The presence of rapid eGFR decline identified TDF recipients at increased risk of tubulopathy

Association of a functional variant downstream of TNFAIP3 with systemic lupus erythematosus

Systemic lupus erythematosus (SLE, MIM152700) is an autoimmune disease characterized by self-reactive antibodies resulting in systemic inflammation and organ failure. TNFAIP3, encoding the ubiquitin-modifying enzyme A20, is an established susceptibility locus for SLE. By fine mapping and genomic re-sequencing in ethnically diverse populations, we fully characterized the TNFAIP3 risk haplotype and identified a TT and gt;A polymorphic dinucleotide (deletion T followed by a T to A transversion) associated with SLE in subjects of European (P = 1.58 × 10-8, odds ratio = 1.70) and Korean (P = 8.33 × 10-10, odds ratio = 2.54) ancestry. This variant, located in a region of high conservation and regulatory potential, bound a nuclear protein complex composed of NF-?B subunits with reduced avidity. Further, compared with the non-risk haplotype, the haplotype carrying this variant resulted in reduced TNFAIP3 mRNA and A20 protein expression. These results establish this TT and gt;A variant as the most likely functional polymorphism responsible for the association between TNFAIP3 and SLE. © 2011 Nature America, Inc. All rights reserved

Delineation of valleys and valley floors

Methods to automatically derive landforms have typically focused on pixel-based, bottom-up approaches and most commonly on the derivation of topographic eminences. In this paper we describe an object-based, top-down algorithm to identify valley floors. The algorithm is based on a region growing approach, seeded by thalwegs with pixels added to the region according to a threshold gradient value. Since such landforms are fiat we compare the results of our algorithm for a particular valley with a number of textual sources describing that valley. In a further comparison, we computed a pixel-based six-fold morphometric classification for regions we classified as either being, or not being, valley floor. The regions classified as valley floor are dominated by pla nar slopes and channels, though the algorithm is robust enough to allow local convexities to be classified as within the valley floor. Future work will explore the delineation of valley sides, and thus complete valleys