10 research outputs found

    Chromosome number and secondary chromosomal associations in wild populations of Geranium pratense L. from the cold deserts of Lahaul-Spiti (India)

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    In this work we studied the meiotic chromosome number and details of secondary chromosomal associations recorded for the first time in Geranium pratense L. from the alpine environments in the cold deserts of Lahaul­Spiti (India). All the presently studied individuals of the species existed at 4x level (x = 14). The present chromosome count of n = 28 in the species adds a new cytotype to the already existing diploid chromosome count of 2n = 28 from the Eastern Himalayas and outside of India. Out of the six accessions scored presently four showed normal meiotic course. However, two accessions investigated from Mud, 3800 m and Koksar, 3140 m depicted abnormal meiotic course due to the presence of multivalents and univalents, and secondary associations of bivalents/chromosomes. The secondary chromosomal associations in the species existed among bivalents/chromosomes were noticed in the PMCs at prophase­I (diakinesis) and persisted till the separation of sister chromatids at M­II. The variation in the number of bivalents/chromosomes involved in the secondary associations at M­I (2–8) and A­I/M­II (2–12) has also been recorded. The occurrence of such secondary associations of bivalents/ chromosomes in G. pratense which existed at 4x level indicated the secondary polyploid nature of the species.Впервые изучены мейотическое число хромосом и особенности вторичных хромосомных ассоциаций растений Geranium pratense L., растущих на альпийских высотах холодных пустынь Lahaul-Spiti (Индия). Все изученные особи были 4х (x = 14). Хромосомный набор n = 28 у этого вида добавляет новый цитотип к уже существующему диплоидному хромосомному набору 2n = 28 из Восточных Гималаев и за пределами Индии. Из шести изученных образцов у четырех установлен нормальный ход мейоза. В то же время два образца из районов Mud, 3800 м, и Koksar, 3140 м демонстрировали аномальное течение мейоза из-за наличия мульти- и унивалентов и вторичные ассоциации биваленты/хромосомы. Вторичные хромосомные ассоциации были замечены в профазе І (диакинез) и существовали до разделения сестринских хроматид на стадии M-II. Отмечена также изменчивость числа бивалентов/хромосом, вовлеченных во вторичные ассоциации на стадиях M­I (2–8) и A­I/M­II (2–12). Наличие у G. pratense таких вторичных ассоциаций, которые существуют на уровне 4x, указывает на вторичную полиплоидную природу этого вида.Вперше вивчено мейотичне число хромосом і особливості вторинних хромосомних асоціацій рослин Geranium pratense L., що ростуть на аль-пійських висотах холодних пустель Lahaul-Spiti (Індія. Всі досліджені особини були 4х (х = 14). Хромосомний набірn = 28 у цього виду додає новий цитотип до вже існуючого диплоїдного хромосомного набору n = 28 зі Східних Гімалаїв та за межами Індії. З шести вивчених зразків у чотирьох був нормальний хід мейозу. У той же час два зразки з районів Mud, 3800 м, і Koksar, 3140 м демонстрували аномальний перебіг мейозу через наявність мульти- та унівалентів і вторинні асоціації біваленти/хромосоми. Вторинні хромосомні асоціації спостерігались в профазі І (діакінез) і існували до поділу сестринських хроматид на стадії M-II. Зазначено також мінливість числа бівалентів/хромосом, залучених у вторинні асоціації на стадіях M­I (2–8) і A­I/M­II (2–12). Наявність у G. pratense таких вторинних асоціацій, які існують на рівні 4x, вказує на вторинну поліплоїдну природу цього виду

    Glass in a Direct Electric Field

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    Environmental Control on Biotic Development in Siberia (Verkhoyansk Region) and Neighbouring Areas During Permian-Triassic Large Igneous Province Activity

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    We propose an updated ammonoid zonation for the Permian-Triassic boundary succession (the lower Nekuchan Formation) in the Verkhoyansk region of Siberia: (1) Otoceras concavum zone (uppermost Changhsingian); (2) Otoceras boreale zone (lowermost Induan); (3) Tompophiceras morpheous zone (lower Induan); and (4) Wordieoceras decipiens zone (lower Induan). The Tompophiceras pascoei zone, previously defined between the Otoceras boreale and Tompophiceras morpheous zones, is removed in our scheme. Instead of this the Tompophiceras pascoei epibole zone is proposed for the lower part of the Tompophiceras morpheous zone. New and previously published nitrogen isotope records are interpreted as responses to climatic fluctuations in the middle to higher palaeolatitudes of Northeastern Asia and these suggest a relatively cool climatic regime for the Boreal Superrealm; however the trend towards warming across the Permian-Triassic boundary transition is also seen. The evolutionary development and geographical differentiation of otoceratid ammonoids and associated groups are considered. It is likely that the Boreal Superrealm was their main refugium, where otocerid, dzhulfitid and some other ammonoids survived the major biotic crisis at the end of the Permian. The similarity of ontogenetic development of suture lines of Otoceras woodwardi Griesbach and O. boreale Spath gives some grounds for suggesting a monophyletic origin of the genus Otoceras, having bipolar distribution

    Polarized Targets

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    A Survey of Karyological Phenomena in the Juncaceae with Emphasis on Chromosome Number Variation and Evolution

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    PHOS Technical Design Report

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    Risk factors for unfavourable postoperative outcome in patients with Crohn's disease undergoing right hemicolectomy or ileocaecal resection. An international audit by ESCP and S-ECCO

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    Aim: Patient- and disease-related factors, as well as operation technique, all have the potential to impact on postoperative outcome in Crohn's disease. The available evidence is based on small series and often displays conflicting results. The aim was to investigate the effect of preoperative and intra-operative risk factors on 30-day postoperative outcome in patients undergoing surgery for Crohn's disease. Method: This was an international prospective snapshot audit including consecutive patients undergoing right hemicolectomy or ileocaecal resection. The study analysed a subset of patients who underwent surgery for Crohn's disease. The primary outcome measure was the overall Clavien\u2013Dindo postoperative complication rate. The key secondary outcomes were anastomotic leak, reoperation, surgical site infection and length of stay in hospital. Multivariable binary logistic regression analyses were used to produce odds ratios and 95% confidence intervals. Results: In all, 375 resections in 375 patients were included. The median age was 37 and 57.1% were women. In multivariate analyses, postoperative complications were associated with preoperative parenteral nutrition (OR 2.36, 95% CI 1.10\u20134.97), urgent/expedited surgical intervention (OR 2.00, 95% CI 1.13\u20133.55) and unplanned intra-operative adverse events (OR 2.30, 95% CI 1.20\u20134.45). The postoperative length of stay in hospital was prolonged in patients who received preoperative parenteral nutrition (OR 31, 95% CI 1.08\u20131.61) and those who had urgent/expedited operations (OR 1.21, 95% CI 1.07\u20131.37). Conclusion: Preoperative parenteral nutritional support, urgent/expedited operation and unplanned intra-operative adverse events were associated with unfavourable postoperative outcome. Enhanced preoperative optimization and improved planning of operation pathways and timings may improve outcomes for patients
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