108 research outputs found

    Law-governed natures of morphological processes in experimental animals bone tissue under the influence of different bone-affinitive medicines

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    У 50 крыс в возрасте 3-х дней, которые были распределены на 5 групп наблюдения, было проведено исследование влияния остеотропных препаратов – остеомага, цинктерала и гидроксиапатита на морфологию костной ткани челюстей при экспериментальном кариесе в течение 1 месяца. Установлено, что наиболее качественно процессы регенерации развиваются при введении в лунку остеомага и цинктерала, что проявляется полной регенерацией костных пластинок на всём протяжении повреждённой костной ткани.У 50 щурів у віці 3 днів, які були розподілені на 5 груп спостереження, було проведено дослідження впливу остеотропних препаратів - остеомагу, цинктералу та гідроксиапатиту на морфологію кісткової тканини щелеп при експериментальному карієсі протягом 1 місяця. Встановлено, що найбільш якісно процеси регенерації розвиваються при введенні у лунку остеомагу і цинктералу, що проявляється повною регенерацією кісткових пластинок на всьому протязі ушкодженої кісткової тканини.On 50 rats 3 days age, wich was differented into 5 observation groups, the inverstigation of influense of bone affinitive medicines-osteomag, zinkteral and hydroxyapatite on the jaws bone tissue in experimental decay conditions during 1 month was conducted. It was established, that in leading into the alveola osteomag and zinkteral, regeneration processes developes the most qualitatively, what is manifesting in bone laminas complete regeneration over the whole length of damaged bone tissue

    Reacquisition of the lower temporal bar in sexually dimorphic fossil lizards provides a rare case of convergent evolution

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    Temporal fenestration has long been considered a key character to understand relationships amongst reptiles. In particular, the absence of the lower temporal bar (LTB) is considered one of the defining features of squamates (lizards and snakes). In a re-assessment of the borioteiioid lizard Polyglyphanodon sternbergi (Cretaceous, North America), we detected a heretofore unrecognized ontogenetic series, sexual dimorphism (a rare instance for Mesozoic reptiles), and a complete LTB, a feature only recently recognized for another borioteiioid, Tianyusaurus zhengi (Cretaceous, China). A new phylogenetic analysis (with updates on a quarter of the scorings for P. sternbergi) indicates not only that the LTB was reacquired in squamates, but it happened independently at least twice. An analysis of the functional significance of the LTB using proxies indicates that, unlike for T. zhengi, this structure had no apparent functional advantage in P. sternbergi, and it is better explained as the result of structural constraint release. The observed canalization against a LTB in squamates was broken at some point in the evolution of borioteiioids, whereas never re-occuring in other squamate lineages. This case of convergent evolution involves a mix of both adaptationist and structuralist causes, which is unusual for both living and extinct vertebrates

    Peatland Initiation, Carbon Accumulation, and 2 ka Depth in the James Bay Lowland and Adjacent Regions

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    Copyright © 2014 University of Colorado at Boulder, Institute of Arctic and Alpine ResearchPeatlands surrounding Hudson and James Bays form the second largest peatland complex in the world and contain major stores of soil carbon (C). This study utilized a transect of eight ombrotrophic peat cores from remote regions of central and northern Ontario to quantify the magnitude and rate of C accumulation since peatland initiation and for the past 2000 calendar years before present (2 ka). These new data were supplemented by 17 millennially resolved chronologies from a literature review covering the Boreal Shield, Hudson Plains, and Taiga Shield bordering Hudson and James Bays. Peatlands initiated in central and northern Ontario by 7.8 ka following deglaciation and isostatic emergence of northern areas to above sea level. Total C accumulated since inception averaged 109.7 ± (std. dev.) 36.2 kg C m–2. Approximately 40% of total soil C has accumulated since 2 ka at an average apparent rate of 20.2 ± 6.9 g C m–2 yr–1. The 2 ka depths correlate significantly and positively with modern gridded climate estimates for mean annual precipitation, mean annual air temperature, growing degree-days > 0 °C, and photosynthetically active radiation integrated over days > 0 °C. There are significantly shallower depths in permafrost peatlands. Vertical peat accumulation was likely constrained by temperature, growing season length, and photosynthetically active radiation over the last 2 ka in the Hudson Bay Lowlands and surrounding regions.US National Science Foundatio

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016
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