Block Inversion Research Articles

Block inversion on finite rich ℘ words

A unified study of inversions on ℘ words resulted from the importance of words and inversions in molecular biology. In this study, we generalize the idea of inversion by using a technique called block inversion on finite rich ℘ words. A comparison of block inversion on finite total words and on finite ℘ words is made. We conclude that the total number of ℘ words in the block inversion set of a finite rich ℘ word of length n is strictly less than 2n–1.

Secure image encryption algorithm using chaos-based block permutation and weighted bit planes chain diffusion

Aiming at the problem of insufficient security of image encryption technology, a secure image encryption algorithm using chaos-based block permutation and weighted bit planes chain diffusion is proposed, which is based on a variant structure of classical permutation-diffusion. During the permutation phase, the encryption operations of dividing an image into sub-block, block scrambling, block rotation and block inversion, negative-positive transformation, color component shuffling are performed sequentially with chaotic sequences of plaintext association. In the chain diffusion stage, different encryption strategies are adopted for the high and low 4-bit planes according to the weight of image information. Theoretical analyses and empirical results substantiate that the algorithm conforms to the cryptographic requirements of confusion, diffusion, and avalanche effects, while possessing excellent numerical statistical properties with a large cryptographic space. Therefore, the cryptanalysis-propelled security enhancement mechanism proposed in this paper effectively amplifies the aptitude of the algorithm to withstand cryptographic attacks.

The complete chloroplast genome sequences of eight Orostachys species: Comparative analysis and assessment of phylogenetic relationships.

We analyzed the complete chloroplast genomes of eight Orostachys species and compared the sequences to those of published chloroplast genomes of the congeneric and closely related genera, Meterostachys and Hylotelephium. The total chloroplast genome length of thirteen species, including the eight species analyzed in this study and the five species analyzed in previous studies, ranged from 149,860 (M. sikokianus) to 151,707 bp (H. verticillatum). The overall GC contents of the genomes were almost identical (37.6 to 37.8%). The thirteen chloroplast genomes each contained 113 unique genes comprising 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Among the annotated genes, sixteen genes contained one or two introns. Although the genome structures of all Orostachys and Hylotelephium species were identical, Meterostachys differed in structure due to a relatively large gene block (trnS-GCU-trnS-GGA) inversion. The nucleotide diversity among the subsect. Orostachys chloroplast genomes was extremely low in all regions, and among the subsect. Appendiculatae, genus Orostachys, and all thirteen chloroplast genomes showed high values of Pi (>0.03) in one, five, or three regions. The phylogenetic analysis showed that Orostachys formed polyphyly, and subsect. Orostachys and Appendiculatae were clustered with Hylotelephium and Meterostachys, respectively, supporting the conclusion that each subsection should be considered as an independent genus. Furthermore, the data supported the taxonomic position of O. margaritifolia and O. iwarenge f. magnus, which were treated as synonyms for O. iwarenge in a previous study, as independent taxa. Our results suggested that O. ramosa and O. japonica f. polycephala were individual variations of O. malacophylla and O. japonica, respectively. The exact taxonomic position of O. latielliptica and the phylogenetic relationship among the three species, O. chongsunensis, O. malacophylla and O. ramosa, should be a topic of future study.

On the Response Matrix–Constant Nodal method applied to [formula omitted] problems with arbitrary L’th-order anisotropic scattering

In this technical note, the spectral Response Matrix–Constant Nodal (RM–CN) method is applied to numerically solve multigroup X,Y-geometry problems in the discrete ordinates formulation with anisotropic scattering including upscattering events. To achieve this goal, the RM–CN equations are applied to L’th-order scattering anisotropy, and are solved with the partial one-node block inversion iterative scheme. The method has generated accurate numerical results to test problems. The results to two representative test problems are presented and discussed in this note.

Three-Dimensional Microwave Imaging: Fast and Accurate Computations with Block Resolution Algorithms.

This paper considers the microwave imaging reconstruction problem, based on additive penalization and gradient-based optimization. Each evaluation of the cost function and of its gradient requires the resolution of as many high-dimensional linear systems as the number of incident fields, which represents a large amount of computations. Since all such systems involve the same matrix, we propose a block inversion strategy, based on the block-biconjugate gradient stabilized (BiCGStab) algorithm, with efficient implementations specific to the microwave imaging context. Numerical experiments performed on synthetic data and on real measurements show that savings in computing time can reach a factor of two compared to the standard, sequential, BiCGStab implementation. Improvements brought by the block approach are even more important for the most difficult reconstruction problems, that is, with high-frequency illuminations and/or highly contrasted objects. The proposed reconstruction strategy is shown to achieve satisfactory estimates for objects of the Fresnel database, even on the most contrasted ones.

A spectral nodal method for the adjoint [formula omitted] neutral particle transport equations in [formula omitted]-geometry: Application to direct and inverse multigroup source-detector problems

In this work, we apply an adjoint technique to solve two-dimensional direct and inverse source-detector transport problems. In order to obtain the neutral-particle importance maps, we have developed the extended adjoint spectral Green’s function constant-nodal (SGF†-CN) method to numerically solve multigroup adjoint transport problems in the discrete ordinates formulation. Described here is the methodology to obtain the discretized SGF†-CN equations and the adjoint partial one-node block inversion scheme used to iteratively solve these equations. Then, the Levenberg–Marquardt method is applied to minimize a least-squares difference in order to identify the multigroup sources. To illustrate the accuracy of the present methodology, we present and discuss numerical results to two typical model problems.

The Stereocontrolled Biosynthesis of Mirror-Symmetric 2,4-Diaminobutyric Acid Homopolymers Is Critically Governed by Adenylation Activations.

Among the four bioactive cationic homo-poly(amino acids) discovered in nature, two are mirror-image isomers of poly(2,4-diaminobutyric acid) (poly-Dab) whose biosynthesis has long been unexplained. Their structural analogy plausibly suggested that they could share a common biosynthetic pathway utilizing ε-poly(l-lysine) synthetase-like enzymology but with an unprecedented process for enantiomeric inversion of polymer building blocks. To investigate this possibility, we comparatively explored the biosynthesis of poly-l-Dab and its mirror-image isomer poly-d-Dab in Streptomyces celluloflavus USE31 and Streptoalloteichus hindustanus NBRC15115, respectively, through genome mining, genetic inactivation, and heterologous expression combined with biochemical assays. While they shared the same biosynthetic pathway, the poly-d-Dab biosynthetic gene cluster additionally harbored the racemase gene. The critical finding that poly-d-Dab synthetase, in contrast to the synthetase generating the l-isomer, selectively activated d-Dab through adenylation conclusively demonstrated that free diffusible d-Dab preactivationally generated by the racemase is directly activated to be incorporated into the polymer. Our study thus represents the first demonstration of the stereoselective biosynthesis of a nonribosomal peptide governed by adenylation activity for a d-amino acid other than alanine. In silico sequence comparison between poly-Dab synthetases allowed us to identify amino acid residues potentially responsible for the discrimination of Dab enantiomers. Our results will provide significant insight not only for the future discovery of novel bioactive cationic poly(amino acids) but also for the creation of designer nonribosomal peptides with d-configuration.

The Adjoint Discrete Ordinates Solution Applied to Direct and Inverse Neutral Particle X, Y-Geometry Source-Detector Problems

Solving the adjoint transport equation allows obtaining maps of the neutral-particle importance to an objective function, e.g., a detector response. In source-detector problems, the adjoint interior source is defined as the macroscopic absorption cross section of the material the detector is made of. Determining the intensity of a source of particles in each energy group (causes) is possible by solving an inverse source-detector problem, given the source location and the detector response (effects). In this work, we present the application of an adjoint technique to solve energy multigroup X,Y-geometry direct and inverse transport problems. In order to obtain the importance maps, we have extended the adjoint spectral Green's function constant-nodal (SGF*-CN) method to numerically solve energy multigroup adjoint transport problems in the discrete ordinates formulation. Described here are the methodology to obtain the discretized SGF*-CNequations and the adjoint partial one-node block inversion scheme used to iteratively solve these equations. We present numerical results to two test problems to illustrate the accuracy of the present methodology.

Estimation of neutron sources driving prescribed power generations in subcritical systems using one-speed two-dimensional discrete ordinates formulations

It is well known that any subcritical system can be driven by time-independent interior sources of neutrons. Thus, we present a methodology to determine the intensities of uniform and isotropic sources of neutrons that must be added inside a subcritical system generating a prescribed steady-state distribution of power. To accomplish this, we use the time-independent, monoenergetic, X,Y-geometry neutron transport equation for the forward transport problem and the equation which is adjoint to it for the adjoint transport problem. The well-known reciprocity relation is used to correlate these two problems, yielding an explicit relation between interior sources and the power generated by the fuel regions. The discrete ordinates (SN) formulation is applied to the forward and adjoint transport problems with the level-symmetric angular quadratures for X,Y-geometry calculations. The adjoint SN problems are solved by a new coarse-mesh method named adjoint response matrix-constant nodal (RM†-CN) method which is used with the adjoint partial one-node block inversion iterative scheme to generate numerical values for the adjoint node-edge average angular fluxes. The RM†-CN method is a companion method of the response matrix-constant nodal method used to solve forward SN transport problems. Numerical results are given to verify the offered methodology.

GRACE score in assessing the risk of hospital outcomes in patients with pulmonary embolism

Aim. To compare the PESI and GRACE scores in assessing the risk of hospital outcomes in patients with pulmonary embolism.Material and methods. The study included 383 patients with pulmonary embolism (PE), hospitalized during the period of April 4, 2003 on September 18, 2014; 190 (49,6%) are men, the average age is 57,4 years±14,4 years. We considered the patient’s anamnesis, complaints, results of biochemical and instrumental tests, as well as the treatment carried out to the patients.Results. According to the risk stratification of PESI score, 86 (22,5%) patients had a very low risk of death, 88 (22,9%) had a low risk, 94 (24,5%) had an intermediate risk, 60 (15,%) — high risk and 55 (14,4%) patients have a very high risk. The combination of three ECG signs (SI-QIII, right bundle branch block and T-wave inversion in V1-V3) was significantly more common in patients with a very high PE risk — 14,5% (p=0,025). The most reliable sign of the most echographic (echoCG) criteria was dilatation of right ventricle (RV) (p=0,009) in a group of patients with a very high PE risk. According to the GRACE scale, 112 (29,2%) patients were assigned to the low risk group, and 271 (70,8%) patients — to the high risk group. ECG signs were observed more frequently in the high risk group: SI-QIII, T-wave inversion in III, V1-V3 leads, right bundle branch block (p<0,05). Pulmonary hypertension and RV dilatation according to echoCG prevailed in the high risk group (98,4% and 85,1%, respectively), p<0,05. The minimum value of points on the GRACE score for the deceased patients was 118 points. The GRACE scale showed high predictive ability with a sensitivity of 96% and a specificity of 63% (AUC=0,811, CI 95% 0,0738-0,884). However, the PESI score had a slightly greater predictive value with a sensitivity of 100% and a specificity of 53% (AUC=0,879 compared with AUC=0,811 for the GRACE scale). Analysis of the PESI and GRACE scores showed a moderate correlation between them (r=0,668).Conclusion. The GRACE score showed a high predictive value for adverse outcomes in PE patients with a sensitivity of 96% and a specificity of 63%. The minimum score on the GRACE score for deceased patients was 118 points.

A composite spatial grid spectral Green's function method for one speed discrete ordinates eigenvalue problems in two-dimensional Cartesian geometry

Spectral Green's function nodal methods (SGF) are well established as a class of coarse mesh methods. For this reason, they are widely used in the solution of neutron transport problems in discrete ordinates formulation (SN). When compared with fine mesh methods, SGF are considered efficient, as solutions are as accurate as, using a smaller number of spatial nodes, reducing floating point operations. However, the development of spectral-nodal methods for XY Cartesian geometries, has been limited due to (a) difficulties in implementing efficient computational algorithms and, (b) high algebraic and computational costs. This is because these methods need to use NBI-type (One-Node Block Inversion) sweep schemes. The composite spatial grid methods were developed to overcome these challenges. In this work, we describe a composite spatial grid spectral-nodal method to solve one-speed discrete ordinate eigenvalue problems in XY Cartesian geometry with isotropic scattering. The discretization is developed into two stages and two 1D problems coupled by transverse leakage terms in each domain region are obtained. In order to converge toward the numerical solution, we used an alternating-direction iterative technique and a modified source iteration sweep scheme. Also, we used the conventional power method to estimate the problem's dominant eigenvalue. Numerical results for benchmark problems are presented to illustrate the accuracy and performance of the developed method. This approach offers more accurate and efficient results for integral quantities if compared with others SGF methods.

Application of an adjoint technique to one–speed [formula omitted]–geometry source–detector transport problems in the discrete ordinates formulation using a spectral nodal method

Described here is an application of an adjoint technique for solving source–detector discrete ordinates (SN) transport problems by using a spectral nodal method. For one–speed X,Y–geometry adjoint SN transport problems, considering linearly anisotropic scattering in non–multiplying media, the coarse–mesh adjoint spectral Green's function–constant nodal (SGF†–CN) method is presented. The discretized SGF†–CN equations are solved by using the adjoint partial one–node block inversion (NBI) iterative scheme. The partial adjoint NBI scheme performs SN transport sweeps from the four corners of the rectangular domain. One uses the most recent estimates for the adjoint node–edge average fluxes in the outgoing directions, to solve the resulting adjoint SN problem in that node for all the incoming adjoint node–edge average fluxes, which constitute the outgoing adjoint node–edge average fluxes for the adjacent nodes in the direction of the transport sweep. Numerical results are given to illustrate the method's accuracy in coarse–mesh adjoint SN calculations and some advantages of using the adjoint technique in source–detector problems.

On the Locality of Transient Electromagnetic Soundings with a Single-Loop Configuration

The possibilities of reconstructing two-dimensional (2D) cross sections based on the data of the profile soundings by the transient electromagnetic method (TEM) with a single ungrounded loop are illustrated on three-dimensional (3D) models. The process of reconstruction includes three main steps: transformation of the responses in the depth dependence of resistivity ρ(h) measured along the profile, with their subsequent stitching into the 2D pseudo section; point-by-point one-dimensional (1D) inversion of the responses with the starting model constructed based on the transformations; and correction of the 2D cross section with the use of 2.5-dimensional (2.5D) block inversion. It is shown that single-loop TEM soundings allow studying the geological media within a local domain the lateral dimensions of which are commensurate with the depth of the investigation. The structure of the medium beyond this domain insignificantly affects the sounding results. This locality enables the TEM to reconstruct the geoelectrical structure of the medium from the 2D cross sections with the minimal distortions caused by the lack of information beyond the profile of the transient response measurements.

Quasi-2D block inversion of large-scale surface nuclear magnetic resonance profile data using a laterally constrained model

The water content of underground structures can be imaged using surface nuclear magnetic resonance (NMR) in one dimension, two dimensions, or recently, three dimensions. The maximum efficiency can be obtained with a coincident loop configuration in a large-scale area, although the resolution is limited. We have developed a quasi-2D block inversion to characterize a horizontal continuous underground aquifer using a laterally constrained model to improve the resolution of thin aquifers and deep aquifers. Through the simulation of flat surface and irregular surface models, a horizontally layered aquifer with continuously variable water content and [Formula: see text] can be imaged through quasi-2D block inversion, which is more optimized than the traditional 1D block or 1D or 2D smooth inversion methods. Finally, using a series of profile data obtained from surface NMR field measurements in Mongolia, we determine that quasi-2D block inversion based on a laterally constrained model can significantly improve the discontinuity and heterogeneity caused by splicing images in a 1D block inversion and can provide a reliable result of the distribution of continuous aquifers for hydrogeology surveys over a large-scale area.

2008年岩手・宮城内陸地震の震源域を対象とした計測震度トモグラフィ解析による減衰構造不均質分布の推定

In the 2008 Iwate-Miyagi Nairiku Earthquake occurred at volcanic area, large amplitude strong ground motions were recorded at observatories near fault region. Because subsurface structure is very complicated in the volcanic area, it is pointed out that considering heterogeneous attenuation structure is important to investigate characteristics of earthquake ground motions. In this study, we conducted tomographic analysis using seismic intensity data of aftershock records for the purpose of estimating heterogeneous attenuation structure. We also tried to reproduce seismic intensity of aftershocks which occurred near and on the asperity of the main shock. By comparing estimated and observed seismic intensity, we indicated how the heterogeneous attenuation structure influenced amplitudes of earthquake ground motions. The tomographic analysis using seismic intensity was conducted in three phases of procedures. First, we obtained an attenuation relationship of seismic intensity using strong motion records of inter-plate and intra-plate earthquakes, and evaluated a site factor of each station. Next, we obtained the attenuation relationship for crustal earthquakes using records of aftershocks assuming the same site factor. We then calculated residuals of each observed and estimated seismic intensity data. Finally, supposing residuals to be attributed to the heterogeneous attenuation structure, a block inversion was conducted dividing the focal area of the main shock to strip form with horizontal sizes of approximately 3km. An attenuation level of each block was expressed as increase/decrease ratio of seismic intensity (we called “G” value). In this block inversion weighting by the ray length which passes through the block, 326 records of Aratozawa Dam, Kurikoma Dam and KiK-net stations IWTH25, IWTH26, MYGH02, IWTH28 and AKTH04 which located near and on the fault plane of main shock were used. To confirm a resolution of G value estimated at each block, we conducted a numerical experiment using checkerboard. Although large errors were found where the number of ray was sparse, errors were less than 10% in most domains on the fault plane of the main shock. We conducted the same inversion using observed records, and found that estimated heterogeneous attenuation structure was very complicated. As indicated in the previous studies, high attenuation zone was distributed around Mt. Kurikoma. Around IWTH25 which located just above side of the main shock hypocenter, low attenuation zone was distributed. Around Aratozawa Dam and Kurikoma Dam, attenuation structure was very complicated too. We tried to reproduce seismic intensity at IWTH25, Aratozawa Dam and Kurikoma Dam for 3 aftershocks which occurred near and on the asperity of the main shock. When uniform attenuation structure was used, the observed seismic intensity of IWTH25 and Aratozawa Dam were larger than estimated. Observed seismic intensities at Kurikoma Dam were slightly smaller than estimated. In the case of considering heterogeneous attenuation, reproducibility of observed records was greatly improved. In case that azimuths of hypocenters are different, amplitudes of the earthquake ground motions are different even if magnitude and hypocentral distance are the same. We concluded that the propagation path greatly influences amplitudes of earthquake ground motions. It is thought that this complicated attenuation structure was one of factors that large amplitude strong ground motions were recorded at particularly IWTH25 and Aratozawa Dam in the main shock.

A hybrid spectral nodal method for multigroup X,Y-geometry discrete ordinates eigenvalue problems

A hybrid spectral nodal method is developed for the solution of multigroup discrete ordinates (SN) eigenvalue problems with isotropic scattering in X,Y geometry. In this method, the spectral diamond - spectral Green's function (SD-SGF) hybrid scheme, originally developed for numerically solving multigroup SN eigenvalue problem in slab geometry with no spatial truncation error, is generalized to solve the energy multigroup transverse-integrated SN nodal equations with constant approximation for the group transverse leakage terms. The resulting SD-SGF-constant nodal (SD-SGF-CN) method is more accurate than conventional nodal methods for criticality calculations because it treats both the scattering and fission source terms exactly; the only approximation involves the transverse leakage terms. This is in contrast to the classic multigroup SN nodal methods, wherein the group transverse leakage terms, the scattering source and the fission source are all approximated, hence decoupling angular directions and energy groups in the transverse integrated SN nodal equations. We solve the SD-SGF-CN equations using the partial one-node block inversion (NBI) iterative scheme (inner iterations) for each estimate of the dominant eigenvalue in the conventional power method (outer iterations). We show numerical results to illustrate the accuracy of the present multigroup SD-SGF-CN method for coarse-mesh calculations.

Genome sequencing and analysis of a granulovirus isolated from the Asiatic rice leafroller, Cnaphalocrocis medinalis.

The complete genome of Cnaphalocrocis medinalis granulovirus (CnmeGV) from a serious migratory rice pest, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), was sequenced using the Roche 454 Genome Sequencer FLX system (GS FLX) with shotgun strategy and assembled by Roche GS De Novo assembler software. Its circular double-stranded genome is 111,246 bp in size with a high A+T content of 64.8% and codes for 118 putative open reading frames (ORFs). It contains 37 conserved baculovirus core ORFs, 13 unique ORFs, 26 ORFs that were found in all Lepidoptera baculoviruses and 42 common ORFs. The analysis of nucleotide sequence repeats revealed that the CnmeGV genome differs from the rest of sequenced GVs by a 23 kb and a 17kb gene block inversions, and does not contain any typical homologous region (hr) except for a region of non-hr-like sequence. Chitinase and cathepsin genes, which are reported to have major roles in the liquefaction of the hosts, were not found in the CnmeGV genome, which explains why CnmeGV infected insects do not show the phenotype of typical liquefaction. Phylogenetic analysis, based on the 37 core baculovirus genes, indicates that CnmeGV is closely related to Adoxophyes orana granulovirus. The genome analysis would contribute to the functional research of CnmeGV, and would benefit to the utilization of CnmeGV as pest control reagent for rice production.

A fine-grained block ILU scheme on regular structures for GPGPUs

Iterative methods based on block incomplete LU (BILU) factorization are considered highly effective for solving large-scale block-sparse linear systems resulting from coupled PDE systems with n equations. However, efforts on porting implicit PDE solvers to massively parallel shared-memory heterogeneous architectures, such as general-purpose graphics processing units (GPGPUs), have largely avoided BILU, leaving their enormous performance potential unfulfilled in many applications where the use of implicit schemes and BILU-type preconditioners/solvers is highly preferred. Indeed, strong inherent data dependency and high memory bandwidth demanded by block matrix operations render naive adoptions of existing sequential BILU algorithms extremely inefficient on GPGPUs. In this study, we present a fine-grained BILU (FGBILU) scheme which is particularly effective on GPGPUs. A straightforward one-sweep wavefront ordering is employed to resolve data dependency. Granularity is substantially refined as block matrix operations are carried out in a true element-wise approach. Particularly, the inversion of diagonal blocks, a well-known bottleneck, is accomplished by a parallel in-place Gauss–Jordan elimination. As a result, FGBILU is able to offer low-overhead concurrent computation at O(n2N2) scale on a 3D PDE domain with a linear scale of N. FGBILU has been implemented with both OpenACC and CUDA and tested as a block-sparse linear solver on a structured 3D grid. While FGBILU remains mathematically identical to sequential global BILU, numerical experiments confirm its exceptional performance on an Nvidia GPGPU.

On the geoelectric structure of the Sphinx Area in Egypt

ABSTRACTA three‐dimensional model of the electrical resistivity of rocks to a depth of 150 m in the Sphinx and the Pyramid of Khephren (Giza, Egypt) area was built using the results of transient electromagnetic soundings. The technology of the soundings, the data processing, and the design of the media’s model as a result of three‐dimensional block inversion are described. The boundary of the Paleogene limestones that form the plateau of the pyramids and the underlying structure of the folded Cretaceous are defined based on geological interpretation.The created plateau model indicated the thickness of the slightly inclined Mokattam limestones varied from 25 m to 150 m within a 1000 × 300 m2 area. Such intense changes in the limestone subface’s altitudes were controlled by the folded structure of the underlying Cretaceous carbonates. Cretaceous carbonates show low electrical resistivity, which is typical for fractured rocks saturated with saline water. Dense Mokattam limestone blocks are broken by water‐saturated zones with sub‐vertical faults in the southwest–northeast direction. The electrical resistivity in the carbonate surface layer, which lies at the base of the pyramids and Sphinx, is heterogeneous with a composition that depends on the clay content and presence of halite.

Higher-level phylogeny of the Hymenoptera inferred from mitochondrial genomes

Higher-level hymenopteran relationships remain unresolved in both morphological and molecular analyses. In this study, we present the most comprehensive analyses of hymenopteran relationships based on 48 mitochondrial (mt) genomes. One complete and two nearly complete mt genomes representing three hymenopteran superfamilies were newly sequenced. We assessed the influence of inclusion/exclusion of 3rd codon positions, alignment approaches, partition schemes and phylogenetic approaches on topology and nodal support within the Hymenoptera. The results showed that the topologies were sensitive to the variation of dataset and analytical approach. However, some robust and highly supported relationships were recovered: the Ichneumonomorpha was monophyletic; the Trigonalyoidea+Megalyroidea and the Diaprioidea+Chalcidoidea were consistently recovered; the Cynipoidea was generally recovered as the sister group to the Diaprioidea+Chalcidoidea. In addition, the monophyletic Aculeata and Proctotrupomorpha were recovered in some analyses. Several gene rearrangements were detected in each of the three newly sequenced mt genomes. Specifically, the Ibalia leucospoides mt genome harbors a large inversion of a gene block from trnE to trnS2. Inverted, duplicated A+T rich regions were detected in the Ibalia leucospoides mt genome, which probably played an important role during the formation of the large gene block inversion via recombination.