Buckling of a growing tissue and the emergence of two-dimensional patterns

The process of biological growth and the associated generation of residual stress has previously been considered as a driving mechanism for tissue buckling and pattern selection in numerous areas of biology. Here, we develop a two-dimensional thin plate theory to simulate the growth of cultured intestinal epithelial cells on a deformable substrate, with the goal of elucidating how a tissue engineer might best recreate the regular array of invaginations (crypts of Lieberkühn) found in the wall of the mammalian intestine. We extend the standard von Kármán equations to incorporate inhomogeneity in the plate’s mechanical properties and surface stresses applied to the substrate by cell proliferation. We determine numerically the configurations of a homogeneous plate under uniform cell growth, and show how tethering to an underlying elastic foundation can be used to promote higher-order buckled configurations. We then examine the independent effects of localised softening of the substrate and spatial patterning of cellular growth, demonstrating that (within a two-dimensional framework, and contrary to the predictions of one-dimensional models) growth patterning constitutes a more viable mechanism for control of crypt distribution than does material inhomogeneity

Likelihood inference for exponential-trawl processes

Integer-valued trawl processes are a class of serially correlated, stationary and infinitely divisible processes that Ole E. Barndorff-Nielsen has been working on in recent years. In this Chapter, we provide the first analysis of likelihood inference for trawl processes by focusing on the so-called exponential-trawl process, which is also a continuous time hidden Markov process with countable state space. The core ideas include prediction decomposition, filtering and smoothing, complete-data analysis and EM algorithm. These can be easily scaled up to adapt to more general trawl processes but with increasing computation efforts.Comment: 29 pages, 6 figures, forthcoming in: "A Fascinating Journey through Probability, Statistics and Applications: In Honour of Ole E. Barndorff-Nielsen's 80th Birthday", Springer, New Yor

Archaeological evaluation : Oldfield Road, Salford

Salford Archaeology was commissioned by Muse Developments to undertake an archaeological evaluation of land on Oldfield Rd (centred on NGR: SJ82573 98439), currently being developed as part of Salford’s regeneration scheme. This report consists of the results of three evaluation trenches excavated in December 2016. An archaeological assessment completed earlier in the year demonstrated the study area had potential for late 18th - 19th buildings, including housing, a public house and the western end of an industrial complex: Islington Mill. No earlier archaeological remains were anticipated given the later development of the site, particularly in the southern part of the site, which was recently occupied by a hostel and leisure complex with deep footings. The accidental loss of a large portion of the cellared housing in the northern part of the site through groundwork restricted potential to a narrow strip, in the middle of the study area. The trenches in the study area confirmed the western limit of the southern wall of late 18th - 19th century mill, which was located to the east of the study area. The trench closest to Oldfield Rd, revealed a series of walls of a cellared building with a partially surviving flagstone floor. This was likely part of the public house, the Jollies. The trench located in the middle part of the site revealed a single brick pad and linear gulley feature, cut into the natural clay. Together these archaeological remains confirm 19th century domestic and industrial activity. The natural clay was observed at approximately 1.5m below the existing ground levels at the south-east side of the site and at 1.9m depth towards the north-west. No earlier archaeological remains were encountered. The results obtained from the evaluation trenches have indicated that no remains of archaeological significance survive within the study area and that no further archaeological work is required

Remarkable stability of an instability-prone lentiviral vector plasmid in Escherichia coli Stbl3

Large-scale production of plasmid DNA to prepare therapeutic gene vectors or DNA-based vaccines requires a suitable bacterial host, which can stably maintain the plasmid DNA during industrial cultivation. Plasmid loss during bacterial cell divisions and structural changes in the plasmid DNA can dramatically reduce the yield of the desired recombinant plasmid DNA. While generating an HIV-based gene vector containing a bicistronic expression cassette 5′-Olig2cDNA-IRES-dsRed2-3′, we encountered plasmid DNA instability, which occurred in homologous recombination deficient recA1 Escherichia coli strain Stbl2 specifically during large-scale bacterial cultivation. Unexpectedly, the new recombinant plasmid was structurally changed or completely lost in 0.5 L liquid cultures but not in the preceding 5 mL cultures. Neither the employment of an array of alternative recA1 E. coli plasmid hosts, nor the lowering of the culture incubation temperature prevented the instability. However, after the introduction of this instability-prone plasmid into the recA13E. coli strain Stbl3, the transformed bacteria grew without being overrun by plasmid-free cells, reduction in the plasmid DNA yield or structural changes in plasmid DNA. Thus, E. coli strain Stbl3 conferred structural and maintenance stability to the otherwise instability-prone lentivirus-based recombinant plasmid, suggesting that this strain can be used for the faithful maintenance of similar stability-compromised plasmids in large-scale bacterial cultivations. In contrast to Stbl2, which is derived wholly from the wild type isolate E. coli K12, E. coli Stbl3 is a hybrid strain of mixed E. coli K12 and E. coli B parentage. Therefore, we speculate that genetic determinants for the benevolent properties of E. coli Stbl3 for safe plasmid propagation originate from its E. coli B ancestor

PERPECAHAN PARTAI ACEH DALAM MENGHADAPI PILKADA TAHUN 2017 (STUDI PENCALONAN ZAINI ABDULLAH SEBAGAI GUBERNUR MELALUI JALUR INDEPENDEN)

RAHMAD RAMADHANOETOMO, 2017 ABSTRAK PERPECAHAN PARTAI ACEH DALAM MENGHADAPI PILKADA TAHUN 2017(Studi Pencalonan Zaini Abdullah SebagaiGubernur Melalui Jalur Independen)Fakultas Ilmu Sosial dan Ilmu PolitikUniversitas Syiah Kuala(ix.64), pp., bibl., app.(Radhi Darmansyah, M.Sc) Konflik di internal Partai Aceh terlihat jelas dengan keikutsertaan Zaini Abdullah dalam kontestasi Pilkada Aceh tahun 2017 melalui jalur independen.Kemudian Zaini Abdullah mengundurkan diri dari Partai Aceh, sebab sesuaidengan Ketentuan dan Peraturan Perundang-Undangan, anggota Partai Politikdiharuskan mundur dari keanggotaan Partai selambat-lambatnya tiga bulansebelum mendaftar dari jalur perseorangan. Adapun tujuan dari penelitian ini adalah untuk mengetahui penyebabterjadinya perpecahan Partai Aceh dalam menghadapi Pilkada tahun 2017 danmengetahui tentang Zaini Abdullah yang memilih mencalonkan diri melaui jalurindependen. Penelitian ini menggunakan metode Kualitatif dengan pendekatanDeskriptif yang mana akan menghasilkan data berupa ucapan, tulisan, dan prilakuorang-orang yang diamati. Hasil Penelitian Ini menunjukkan aktor konflik dalam konflik internalPartai Aceh merupakan pihak-pihak elit politik yang mengambil tindakanmasing-masing dengan tujuan masing-masing. Jika dilihat dari pandangan PartaiAceh yang menjadi aktor konflik adalah Zaini Abdullah yang memilihmencalonkan diri secara independen. Akan tetapi jika melihat dari tim pemenanganAZAN maka yang menjadi aktor konflik adalah pihak-pihak yang tidakbertanggung jawab dan menginginkan kekuasaan dalam Partai Aceh. Faktorpenyebab terjadinya konflik dalam Partai Aceh adalah karena ada keinginanberbeda dari setiap elit politik yang tidak bisa disatukan. Dampak konflik internalPartai Aceh yang muncul adalah struktur Partai Aceh mengalami kekosongan,perubahan penilaian masyarakat, AD-ART Partai terganggu dan Partai Aceh tidakbisa mempertahankan loyalitas elit politik maupun kader.Kata Kunci : Perpecahan, Partai Aceh, Pencalonan Gubernur, Jalur Independen