3,155 research outputs found
Reply to “Comment on ‘Attenuation, source parameters and site effects in the Irpinia–Basilicata region (southern Apennines, Italy)’ by I.B. Morozov”
No full textWe thank Igor B. Morozov for his interest in our article and for his comment (Morozov 2011)
regarding the non-parametric attenuation curves for the Irpinia–Basilicata region obtained
by generalized spectral inversion (Cantore et al. 2011). Morozov's comment has its root in a
new model proposed by Morozov (2008, 2010) for the interpretation of seismic attenuation
data, where the author comes to the conclusion that the typically used geometrical
spreading terms are oversimplified and argues in favor of a new geometrical spreading ...Published91-934T. Fisica dei terremoti e scenari cosismiciJCR Journalrestricte
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Efficient Delaunay Tessellation through K-D Tree Decomposition:
Get PDFDelaunay tessellations are fundamental data structures in computational geometry. They are important in data analysis, where they can represent the geometry of a point set or approximate its density. The algorithms for computing these tessellations at scale perform poorly when the input data is unbalanced. We investigate the use of k-d trees to evenly distribute points among processes and compare two strategies for picking split points between domain regions. Because resulting point distributions no longer satisfy the assumptions of existing parallel Delaunay algorithms, we develop a new parallel algorithm that adapts to its input and prove its correctness. We evaluate the new algorithm using two late-stage cosmology datasets. The new running times are up to 50 times faster using k-d tree compared with regular grid decomposition. Moreover, in the unbalanced data sets, decomposing the domain into a k-d tree is up to five times faster than decomposing it into a regular grid
Structure of human mitochondrial RNA polymerase elongation complex
Get PDFHere we report the crystal structure of the human mitochondrial RNA polymerase (mtRNAP) transcription elongation complex, determined at 2.65-Å resolution. The structure reveals a 9-bp hybrid formed between the DNA template and the RNA transcript and one turn of DNA both upstream and downstream of the hybrid. Comparisons with the distantly related RNA polymerase (RNAP) from bacteriophage T7 indicates conserved mechanisms for substrate binding and nucleotide incorporation but also strong mechanistic differences. Whereas T7 RNAP refolds during the transition from initiation to elongation, mtRNAP adopts an intermediary conformation that is capable of elongation without refolding. The intercalating hairpin that melts DNA during T7 RNAP initiation separates RNA from DNA during mtRNAP elongation. Newly synthesized RNA exits toward the pentatricopeptide repeat (PPR) domain, a unique feature of mtRNAP with conserved RNA-recognition motifs
A novel intermediate in transcription initiation by human mitochondrial RNA polymerase
Get PDFThe mitochondrial genome is transcribed by a single-subunit T7 phage-like RNA polymerase (mtRNAP), structurally unrelated to cellular RNAPs. In higher eukaryotes, mtRNAP requires two transcription factors for efficient initiation—TFAM, a major nucleoid protein, and TFB2M, a transient component of mtRNAP catalytic site. The mechanisms behind assembly of the mitochondrial transcription machinery and its regulation are poorly understood. We isolated and identified a previously unknown human mitochondrial transcription intermediate— a pre-initiation complex that includes mtRNAP, TFAM and promoter DNA. Using protein– protein cross-linking, we demonstrate that human TFAM binds to the N-terminal domain of mtRNAP, which results in bending of the promoter DNA around mtRNAP. The subsequent recruitment of TFB2M induces promoter melting and formation of an open initiation complex. Our data indicate that the pre-initiation complex is likely to be an important target for transcription regulation and provide basis for further structural, biochemical and biophysical studies of mitochondrial transcription
Spline- and tensor-based signal reconstruction : from structure analysis to high-performance algorithms to multiplatform implementations and medical applications
Get PDFThe problem of signal reconstruction is of fundamental practical value for many applications associated with the field of signal and image processing. This work considers a particular setting where the problem is formulated using a spline-based variational approach. We mainly concentrate on the following four problem-related aspects: 1). analysis of the problem structure, 2). structure-driven derivation of high-performance solving algorithms, 3). high-performance
algorithm implementations and 4). translation of these results to medical applications.
The second chapter of this work presents a tensor-based abstraction for formulation and efficient solving of problems arising in the field of multidimensional data processing. In contrast to traditional matrix abstraction the proposed approach allows to formulate tensor structured problems in an explicitly multidimensional way with preservation of the underlying structure of
computations that, in turn, facilitates the derivation of highly efficient solving algorithms. In addition to being a very helpful tool for our specific problem, the proposed tensor framework with its differentiating features is well suitable for implementing a tensor programming language that offers self-optimized computations of tensor expressions by semantic analysis of their terms.
The third chapter presents a practical example how the proposed tensor abstraction can be used for solving a problem of tensor B-spline-based variational reconstruction of large multidimensional images from irregularly sampled data. Based on our tensor framework we performed a detailed analysis of the problem formulation and derived highly efficient iterative solving algorithm, which offers high computational performance when implemented on computing platforms such as multi-core and GPGPU. We successfully applied the proposed approach to a real-life medical problem of ultrasound image reconstruction from a very large set of four-dimensional (3-D+time) non-uniform measurements.
The fourth chapter presents an alternative approach to the problem of variational signal reconstruction that is based on inverse recursive filtering. We revisited a B-spline-based formulation of this problem via a detailed analysis of the problem structure moving from the uniform towards non-uniform sampling settings. As a result we derived highly efficient algorithms for computing smoothing splines of any degree with an optimal choice of regularization parameter. We extended the presented approach to higher dimensions and showed how a rich variety of non-separable multidimensional smoothing spline operators and the corresponding solutions can be computed with high efficiency. We successfully applied the proposed inverse recursive filtering approach to the problem of medical Optical Coherence Tomography.
We conclude our work by presenting a high-level approach to software/hardware co-design of high-performance streaming data processing systems on FPGA. This approach allows to develop hybrid application specific system designs by combining the flexibility of multi-processor-based systems and high-performance of dedicated hardware components. A high-level programming model that is at the center of the approach along with an integrated development environment, implemented based on its principles, allow software and signal processing engineers who are not FPGA experts to design high-performance hardware architectures in a short time. We show some examples of how the developed framework can be efficiently used for implementation of our tensor- and spline-based algorithms
A model for transcription initiation in human mitochondria.
Get PDFRegulation of transcription of mtDNA is thought to be crucial for maintenance of redox potential and vitality of the cell but is poorly understood at the molecular level. In this study we mapped the binding sites of the core transcription initiation factors TFAM and TFB2M on human mitochondrial RNA polymerase, and interactions of the latter with promoter DNA. This allowed us to construct a detailed structural model, which displays a remarkable level of interaction between the components of the initiation complex (IC). The architecture of the mitochondrial IC suggests mechanisms of promoter binding and recognition that are distinct from the mechanisms found in RNAPs operating in all domains of life, and illuminates strategies of transcription regulation developed at the very early stages of evolution of gene expression
Application of the chi(2) principle and unbiased predictive risk estimator for determining the regularization parameter in 3-D focusing gravity inversion
Get PDFabstract: The χ[superscript 2] principle and the unbiased predictive risk estimator are used to determine optimal regularization parameters in the context of 3-D focusing gravity inversion with the minimum support stabilizer. At each iteration of the focusing inversion the minimum support stabilizer is determined and then the fidelity term is updated using the standard form transformation. Solution of the resulting Tikhonov functional is found efficiently using the singular value decomposition of the transformed model matrix, which also provides for efficient determination of the updated regularization parameter each step. Experimental 3-D simulations using synthetic data of a dipping dike and a cube anomaly demonstrate that both parameter estimation techniques outperform the Morozov discrepancy principle for determining the regularization parameter. Smaller relative errors of the reconstructed models are obtained with fewer iterations. Data acquired over the Gotvand dam site in the south-west of Iran are used to validate use of the methods for inversion of practical data and provide good estimates of anomalous structures within the subsurface.This is a pre-copy-editing, author-produced PDF of an article accepted for publication in GEOPHYSICAL JOURNAL INTERNATIONAL following peer review. The definitive publisher-authenticated version Vatankhah, Saeed, Ardestani, Vahid E., & Renaut, Rosemary A. (2015). Application of the chi(2) principle and unbiased predictive risk estimator for determining the regularization parameter in 3-D focusing gravity inversion. GEOPHYSICAL JOURNAL INTERNATIONAL, 200(1), 265-277. http://dx.doi.org/10.1093/gji/ggu397 is available online
Облачная версия метода сравнительного расчета прогнозирования свойств веществ и систем
Get PDFKobelnik, A. E.; Morozov, K. A.; Sudarikov, A. I.; Naryshkin, D. G. Cloud version of the comparative calculation method for predicting the properties of substances and system
О вычислительных конструкциях в функциональных пространствах
Get PDFNumerical study of various processes leads to the need for clarification (extensions) of the limits of applicability of computational constructs and modeling tools. In this article, we study the differentiability in the space of Lebesgue integrable functions and the consistency of this concept with fundamental computational constructions such as Taylor expansion and finite differences is considered. The function from is called -differentiable at the point from if there exists an algebraic polynomial of degree no higher than such that the integral over the segment from then for there is Formulas are found for calculating coefficients of such representing the limit of the ratio of integral modifications of finite differences to It turns out that if and is -differentiable at the point then is approximated by a Taylor polynomial up to and the expansion coefficients can be found in the above way. To study functions from on a set, a discrete "global" construction of a difference expression is used: based on the quotient and the sequence is built \big{{\bf\Lambda}_n^m[f]\big} of piecewise constant functions subordinate to partitions half-interval into equal parts. It is shown that for a -differentiable at the point function the sequence \big{{\bf\Lambda}_n^m[f]\big},\; m=1,\cdots, k, converge as at this point to the coefficients of the polynomial approximating the function at it. Using \big{{\bf\Lambda}_n^k[f]\big} the following theorem is established: {\it " from belongs to is uniformly -differentiable on ".} A special place is occupied by the study of constructions corresponding to the case We consider them in where is a cube in the space Given a function and a partition of a semi-closed cube on equal semi-closed cubes we construct a piecewise constant function , defined as the integral average on each cube This computational construction leads to the following theoretical facts: {\it 1) from belongs to L_p, 1 \le p < \infty, \Longleftrightarrow \big{\Theta_n[f] \big} converges in the boundedness of \big{\Theta_n[f]\big} \; \Longleftrightarrow f\!\in\!L_\infty; 2) sequences \big{\Theta_n[\cdot]\big} define on the equivalence classes the operator-projector in the space 3) for the function we get where is the space of bounded functions, and is the function extended on a set of measure zero and the equality } Thus, in the family of spaces one can replace with Численное исследование различных процессов приводит к необходимости уточнения (расширения) границ применимости вычислительных конструкций и инструментов моделирования. В настоящей статье изучается дифференцируемость в пространстве интегрируемых по Лебегу функций и рассматривается согласованность этого понятия с основополагающими вычислительными построениями такими, как разложение Тейлора и конечные разности. Функцию из назовём -дифференцируемой в точке из если существует алгебраический многочлен степени не выше такой, что интеграл по отрезку от до для есть Найдены формулы для вычисления коэффициентов такого представляющие собой предел отношения интегральных модификаций конечных разностей к Получается, что если и является -диффе\-ренци\-руемой в точке то приближается тейлоровским многочленом с точностью а коэффициенты разложения могут быть найдены указанным выше способом. Для исследования функций из на множестве применяется дискретная «глобальная» конструкция разностного выражения: на основе частного и строится последовательность \big{{\bf\Lambda}_n^m[f]\big} кусочно-постоянных функций, подчинённых разбиениям полуинтервала на равных частей. Показано, что для -диффе\-ренци\-руемой в точке функции последовательности \big{{\bf\Lambda}_n^m[f]\big},\; m=1,\cdots, k, сходятся при в этой точке к коэффициентам приближающего в ней функцию многочлена. С помощью \big{{\bf\Lambda}_n^k[f]\big} устанавливается теорема: {\it « из принадлежит равномерно -диффе\-рен\-цируе\-ма на ».} Отдельное место занимает изучение построений, соответствующих случаю Их рассматриваем в где -- куб в пространстве По заданной функции и разбиению полузамкнутого куба на равных полузамкнутых кубов построим кусочно-постоянную функцию , определяемую как интегральное среднее на каждом кубе Данная вычислительная конструкция приводит к следующим теоретическим фактам: {\it 1) из принадлежит L_p, 1 \le p < \infty, \Longleftrightarrow \big{\Theta_n[f]\big} сходится в ограниченность \big{\Theta_n[f]\big} \; \Longleftrightarrow f\!\in\!L_\infty; 2) последовательности \big{\Theta_n[\cdot]\big} определяют на классах эквивалентности оператор-проектор в пространстве 3) для функции получаем где -- это пространство ограниченных функций, а -- доопределённая на множестве меры ноль функция и выполняется равенство } Таким образом, в семействе пространств можно заменить на $B[Q_0].
Fatkullina imitata Grischenko & Gordon & Morozov 2018, n. sp.
No full text<i>Fatkullina imitata</i> n. sp. <p>(Figs 1 A–D, 2–6; Table 1)</p> <p> <i>Fatkullina</i> sp.: Grischenko 2015: 39 (table 1).</p> <p> <b>Material examined.</b> <i>Holotype</i>: ZIRAS 1 /50661, colony (18 × 17 mm) encrusting flattened pebble; KamchatNIRO Collection, R.V. <i>Agat</i>, 16 June 2008, Stn 2–S–2, continental slope of western Kamchatka Peninsula, Sea of Okhotsk, 58.03833° N, 155.72028° E, depth 290 m, on pebbles, coll. S.G. Korostylyov. <i>Paratype</i> 1: ZIRAS 2 / 50662, two colonies (23 × 21 mm, 15 × 12 mm) encrusting broken fragment of bivalve shell <i>Chlamys</i> sp.; same data as for holotype. <i>Paratype</i> 2: ZIRAS 3 /50663, 12 fragments of single colony detached from pebble; KamchatNIRO Collection, R.V. <i>Professor Kizevetter</i>, 3 July 2015, Stn 73, shelf of western Kamchatka Peninsula, Sea of Okhotsk, 58.13333° N, 156.01889° E, depth 145 m, on rock and shell, coll. T.B. Morozov. <i>Paratype</i> 3: ZIRAS 4 /50664, seven intact ancestrular colonies; same data as for paratype 2. <i>Paratype</i> 4: ZIRAS 5 /50665, ancestrular colony (4 × 3 mm) encrusting broken fragment of <i>Chlamys</i> sp; same data as for holotype. <i>Paratype</i> 5: ZIRAS 6 /50666, colony (8 × 7 mm) detached from pebble; KamchatNIRO Collection, R.V. <i>Agat</i>, 16 June 2008, Stn 1–K–2, continental slope of western Kamchatka Peninsula, Sea of Okhotsk, 58.01917° N, 155.71667° E, depth 285 m, on pebbles, coll. S.G. Korostylyov. <i>Paratype</i> 6: NHMUK 2017.7.11.7, extensive colony (35 × 29 mm) encrusting cirripede fragment (with adjacent tiny colony—ancestrula and single daughter zooid); same data as for holotype. <i>Paratype</i> 7: NHMUK 2017.7.11.8, colony encrusting fragment of <i>Chlamys</i> sp; KamchatNIRO Collection, R.V. <i>Professor Probatov</i>, 11 August 2013, Stn 82, shelf of western Kamchatka Peninsula, Sea of Okhotsk, 58.15000° N, 156.05000° E, depth 146 m, on gravel from silty sand, coll. T.B. Morozov. <i>Paratype</i> 8: NIWA 127751, colony (33 × 30 mm) encrusting fragment of <i>Chlamys</i> sp., with adjacent colony and tiny ancestrular colonies; same data as for paratype 7. <i>Additional material</i>: KamchatNIRO Collection, R.V. <i>Agat</i> (2008): Stn 2–S–2, one specimen; Stn 3–W–1, two specimens; Stn 3–W–2, six specimens; Stn 4–N–2, one specimen; Stn 5–E–1, one specimen; Stn 5–E–2, three specimens. R.V. <i>Professor Probatov</i> (2013): Stn 62, four specimens; Stn 63, one specimen; Stn 82, 13 specimens. R.V. <i>TINRO</i> (2014): Stn 63, one specimen; Stn 69, one specimen; Stn 82, eight specimens. R.V. <i>Professor Kizevetter</i> (2015): Stn 73, 96 specimens. R.V. <i>TINRO</i> (2016): Stn 74, 43 specimens.</p> <p> <b>Etymology.</b> Latin adjective <i>imitatus</i> (imitated, copied), alluding to the strong resemblance to the type species of the genus, <i>Fatkullina paradoxa</i>.</p> <p> <b>Description.</b> Colony encrusting, multiserial, unilaminar, more or less circular, with undulating margin, attaining <i>c</i>. 40 mm diameter. Colour (when dried) crimson (most typical), pink, dark red, deep purple to black (Fig. 1 A–D); preserved polypides pink. Zooids relatively large, greatly variable in form (Figs 2A, B, 3C, D) including broadly hexagonal, oval, quadrangular, rhombic, pyriform, polygonal or irregular in outline, arranged quincuncially or less orderly, separated by fine undulating sutures between vertical walls; sutures occasionally concealed by secondary calcification.</p> <p>Frontal shield (Figs 3 C–F, 4A–C, 5F, G) lepralioid, thick, convex, most elevated and inflated in distal third of zooid around secondary orifice, moderately convex to evenly flattened centrally and proximally; with finely granular-tubercular surface, uniformly perforated with conspicuous round to elongate oval areolar-septular pores along zooidal margins and numerous smaller, circular frontal pseudopores (Figs 3E, F, 5B, F, G); areolae and pseudopores becoming funnel-shaped with development of secondary calcification, with granulation extending deep inside; some pores occluded. Interior surface of frontal shield (Fig. 5D, E, G) smooth, with numerous openings of pseudopores in center, and openings of tubular areolar pore channels around periphery. Some zooids, especially in elevated older parts of colony, with more-elongated area of calcification distal to orifice, with up to 3– 4 rows of pseudopores (Fig. 4 A–C). Distal margin of secondary orifice can bear a solid, elevated, conical or bulbous umbo (Fig. 4A, B, arrowheads), with orifice shifted proximally to a position about 1/4 to 1/3 zooid length from distal end. Two smaller, conical umbones can additionally flank sinus of secondary orifice, strongly reducing area of secondary orifice and conferring strictly triangular form.</p> <p> Primary orifice (Fig. 5 A–C, E) deeply sunken, wholly visible only at colony margin; transversely oval, with straight or weakly concave proximal margin and short, narrow U-shaped sinus; thin proximal margin lacking granulation. In fully completed zooids, primary orifice tilted proximally at angle of <i>c</i>. 20–40° to frontal plane. Secondary orifice (Figs 3E, 5B) formed by thickening of frontal shield around primary orifice; roughly triangular to drop-shaped in outline, with finely granular tubercular margin; at highest elevation of frontal shield. Distal margin gently convex, arching and overhanging 1/3 to 2/3 of distal part of primary orifice and partially concealing its lateral margins (Fig. 5B, C). Proximolateral margins sloping abruptly within, forming broad to narrowly triangular pseudosinus descending to smooth suboral rim of primary orifice. Lumen of secondary orifice (Figs 3E, F, 5C, E, G) deep, tubular to infundibular, tilted proximally at angle about 30–45° to frontal plane. Some zooids in central colony region secondarily kenozooidal (Fig. 4 D–F), with orifice constricted or closed, often with a cylindrical or mammiform projection over orifice. Operculum dark brown. Oral spines, avicularia and ooecia absent.</p> <p>Larval incubation presumably occurs in internal brood sac. Interzooidal communication via uniporous septula recessed between buttresses (Fig. 3A, B). Basal wall fully calcified (Fig. 5F, G). Zooidal morphogenesis with reversed polarity, i.e. orifice situated at proximal end of zooid relative to colony orientation and directed towards ancestrula. Kenozooids rarely single, distributed among autozooids, more frequently multiple, united into clusters.</p> <p>Ancestrula (Fig. 6 A–H) resembling autozooids in general appearance; roughly hexagonal, convex, with finely granular surface and a few marginal and frontal pores. Ancestrular orifice circular, with deep V-shaped sinus; cormidial, bounded proximally by distal part of frontal shield, distally and laterally by margins of vertical walls of distal and lateral periancestrular zooids; boundaries defined by fine sutures externally (Fig. 6B) and internally (Fig. 6F, arrowheads). Interior of ancestrular frontal shield (Fig. 6 D–F) with mixed (suboral umbonuloid and proximal lepralioid) components; suboral part unequally divided by four radial sutures (Fig. 6F, arrowheads), two of them flanking the sinus, apparently corresponding externally (in part, at least) to sutures seen frontally between other components of ancestrular complex. Ring scar discrete (Fig. 6F), forming very regular boundary between exteriorwall microstructure (planar-spherulitic fabric) of umbonuloid part and extra-umbonuloid calcification. Umbo extensive, occupying about 58% of length of frontal shield. Proximal lepralioid part of shield with smooth interior surface containing scattered tiny, uniformly circular, pseudopores (Fig. 6E). Ancestrula unrecognizable in older region of large colonies owing to secondary calcification that conceals orifices and crosses zooidal boundaries.</p> <p>Ancestrula buds triplet of somewhat spirally arranged periancestrular zooids, integrated into ancestrular complex. First daughter zooid of complex differentiating distally (Fig. 6A, D), perpendicular to ancestrula, slightly curved along long axis, giving T-shaped appearance to initial stage of ancestrular complex (seen in a dozen such newly established colonies), and two periancestrular zooids then differentiating laterally on each side. Orifices of distolateral zooids can be orientated antiparallel to ancestrula (Fig. 6B, C, right zooid; Fig. 6G, left zooid) or same direction as ancestrula (Fig. 6G, right zooid). Weakly spiral budding pattern continued through zone of astogenetic change and visible throughout four to ten or more generations of zooids distant from ancestrula.</p> <p> <b>Remarks.</b> In having zooids with reversed polarity and occasionally possessing deep-purple to black colony colour, <i>Fatkullina imitata</i> <b>n. sp.</b> strongly resembles the type species of the genus, <i>F. paradoxa</i>, and can be confused with it. The two species differ, however, in the following characters:</p> <p> 1 Frontal shield convexity—maximally convex centrally to proximally, with a comparatively depressed orificial area in <i>F. paradoxa</i>; typically most elevated and inflated distally in circumorificial area, and moderately convex proximally in <i>F. imitata</i> <b>n. sp.</b></p> <p> 2 Umbo(nes)—a prominent solid umbo or 2–3 smaller, scattered mamilliform umbones in the suboral/ subcentral part of the frontal shield in many zooids of <i>F. paradoxa</i>; a conical to bulbous umbo occasionally developing distal to the orifice in some zooids of <i>F. imitata</i> <b>n. sp.</b>, particularly in elevated older parts of colony. Further, 2–3 smaller umbones can occasionally replace the single prominent umbo randomly over the whole frontal shield in <i>F. paradoxa</i>, whereas a pair of smaller umbones may flank the sinus proximolaterally in <i>F. imitata</i> <b>n. sp.</b></p> <p> 3 Shape of the primary orifice—more or less circular in outline (mean length and width 0.20 × 0.21 mm in type material) with a deep, widely V-shaped sinus in <i>F. paradoxa</i>; transversely oval (mean length and width 0.12 × 0.19 mm) with a straight proximal margin and narrowed, shallow U-shaped sinus in <i>F. imitata</i> <b>n. sp.</b></p> <p> 4 Depth of the primary orifice—little sunken, facing frontally and wholly visible in all zooids at all stages of astogeny in <i>F. paradoxa</i>; deeply sunken, tilted proximally at about 20–40° to frontal plane, and partly concealed by the overhanging distal margin of the secondary orifice for 1/3 to 1/2 of its length, hence wholly visible only in developing zooids near the colony margin in <i>F. imitata</i> <b>n. sp.</b></p> <p> 5 Relative proportions of the orifice—orifice width and sinus length are very similar and overlapping in <i>F. paradoxa</i> and <i>F. imitata</i> <b>n. sp.</b>, respectively 0.19–0.24 mm (0.21 ± 0.02 mm) vs 0.16–0.23 mm (0.19 ± 0.02 mm), and 0.03–0.05 mm (0.04 ± 0.01 mm) vs 0.02–0.05 mm (0.03 ± 0.01 mm), whereas orifice length in <i>F. paradoxa</i> exceeds that in <i>F. imitata</i> <b>n. sp.</b> (0.18–0.25 mm (0.20 ± 0.02 mm) vs 0.10–0.15 mm (0.12 ± 0.02 mm)) and the ranges do not overlap.</p> <p> 6 Ratio of primary orifice length to zooid length—half as great in <i>F. imitata</i> <b>n. sp.</b> (about 14%) compared to <i>F. paradoxa</i> (about 29%).</p> <p> 7 Secondary orifice—the primary and secondary orifices are nearly identical in form and roughly circular in <i>F. paradoxa</i>; the primary orifice is transversely oval and the secondary orifice triangular to drop-shaped in outlines in <i>F. imitata</i> <b>n. sp.</b></p> <p> 8 The cormidial nature of the primary orifice—cormidial in several generations of periancestrular zooids in <i>F. paradoxa</i>; cormidial only in zooids of the ancestrular complex in <i>F. imitata</i> <b>n. sp.</b></p> <p> 9 Colour of dried colonies (colour not seen in living colonies)—black in <i>F. paradoxa</i>; mostly dark red/crimson in <i>F. imitata</i> <b>n. sp.</b> (sometimes pink, rarely deep purple to black).</p> <p> <b>Ecology.</b> The new species was documented in areas of mixed hard and soft bottoms, including pebbles and rocks with shell, gravel and sand/silt admixtures. Of the 197 colonies examined, 79.69% were found on pebbles, 10.15% and 1.02% respectively on shell fragments of the bivalves <i>Chlamys</i> sp. and <i>Monia macrochisma</i>, 8.12% on barnacles, 0.51% on tubes of serpulid polychaetes and 0.51% on sponges. Co-occurring invertebrates mostly included the echinoderms <i>Strongylocentrotus pallidus</i> and <i>Ophiura leptoctenia</i>, the sedentary polychaetes <i>Scoloplos armiger</i> and <i>Galathowenia oculata</i>, the gammaridean amphipod <i>Melita dentata</i> and the bivalve <i>Yoldia myalis</i>, as well as hydroids, barnacles, sponges and about 70–90 other bryozoan species, the most abundant being <i>Hippothoa arctica</i> (Kluge, 1906), <i>H</i>. <i>expansa</i> Dawson, 1859, <i>Escharella ventricosa</i> (Hassall, 1842), <i>Ragionula rosacea</i> (Busk, 1856) and <i>Stomacrustula tuberculata</i> (Androsova, 1958). The number of <i>F</i>. <i>imitata</i> colonies/m 2 by collection year was 4–28 (2008), 4–40 (2013), 4–32 (2014), 384 (2015) and 172 (2016). Colonies of <i>F</i>. <i>imitata</i> occasionally cover a considerable area of any particular substratum, appearing as the ‘background’ species at certain sites where shingly bottoms prevail.</p> <p> <b>Distribution.</b> <i>Fatkullina imitata</i> <b>n. sp.</b> is currently known from 16 stations in the depth range 100–361 m, in an area bounded by the coordinates 56.98389– 58.18528° N and 154.93389– 156.05000° E. It can thus be categorized as a high-Boreal, Pacific, Asian, sublittoral to upper bathyal species, endemic to the western Kamchatka shelf and slope, Sea of Okhotsk.</p>Published as part of <i>Grischenko, Andrei V., Gordon, Dennis P. & Morozov, Taras B., 2018, Fatkullina imitata n. sp., second species of a unique cheilostome bryozoan genus with reversed-polarity zooidal budding, and new family Fatkullinidae in Zootaxa 4508 (1)</i>, DOI: 10.11646/zootaxa.4508.1.4, <a href="http://zenodo.org/record/2606858">http://zenodo.org/record/2606858</a>
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