Nuclear Region Research Articles

Evaluation of the Impact of Population Management on the Genetic Parameters of Selected Spiral-Horned Antelopes.

The rapid loss of biodiversity and the associated reduction and fragmentation of habitats means that ex situ populations have become an important part of species conservation. These populations, which are often established from a small number of founders, require careful management to avoid the negative effects of genetic drift and inbreeding. Although the inclusion of molecular data is recommended, their availability for captive breeding management remains limited. The aim of this study was to evaluate the relationship between the levels of genetic diversity in six spiral-horned antelope taxa bred under human care and their respective management strategies, conservation status, demography, and geographic origin, using 10 nuclear DNA microsatellite loci and mitochondrial control region DNA sequences. Our findings include associations between genetic diversity and management intensity but also with the diversity and contribution of wild populations to captive founders, with some populations apparently composed of animals from divergent wild lineages elevating captive genetic diversity. When population sizes are large, the potential advantages of maximizing genetic diversity in widely outcrossed populations may need careful consideration with respect to the potential disruption of adaptive diversity. Genetic data serve as a robust tool for managing captive populations, yet their interpretation necessitates a comprehensive understanding of species biology and history.

Rambellisea gigliensis and Rambellisea halocynthiae, gen. et spp. nov. (Lulworthiaceae) from the Marine Tunicate Halocynthia papillosa.

In this study, 15 Lulworthiales strains isolated from the marine tunicate Halocynthia papillosa collected in the central Tyrrhenian Sea were characterized using a polyphasic approach (morpho-physiological, molecular, and phylogenetic analyses). Based on multi-locus phylogenetic inference and morphological characters, a new genus, Rambellisea, and two new species, R. halocynthiae and R. gigliensis (Lulworthiales), were proposed. Multi-locus phylogenetic analyses using the nuclear ribosomal regions of DNA (nrITS1-nr5.8S-nrITS2, nrLSU, and nrSSU) sequence data strongly supported the new taxa. Phylogenetic inference, estimated using Maximum Likelihood and Bayesian Inference, clearly indicates that Rambellisea gen. nov. forms a distinct clade within the order Lulworthiales. Moreover, the two new species were separated into distinct subclades, solidly supported by the analyses. This is the first report of Lulworthiales species isolated from animals.

Nuclear regions as seen with LOFAR international baselines

Context. Radio galaxies dominate the sky at radio wavelengths and represent an essential piece in the galaxy evolution puzzle. High-resolution studies focussed on statistical samples of radio galaxies are expected to shed light on the triggering mechanisms of the active galactic nucleus in their centre, alternating between the phases of activity and quiescence. Aims. For this work, we zoomed in on the sub-arcsec radio structures in the central regions of the 35 radio galaxies in the area covering 6.6 deg2 of the Lockman Hole region. The sources studied here were previously classified as active, remnant, and candidate restarted radio galaxies based on the LOw Frequency ARray (LOFAR) observations at 150 MHz. We examined the morphologies and studied the spectral properties of their central regions to explore their evolutionary stages and to revise the morphological and spectral criteria used to select the initial sample. Methods. We used the newly available LOFAR 150 MHz image obtained using international baselines, yielding a resolution of 0.38″ × 0.30″, making this the first systematic study of the nuclear regions at such a high resolution and low frequency. We used publicly available images from the Faint Images of the Radio Sky at Twenty-cm survey at 1.4 GHz and the Karl G. Jansky Very Large Array (VLA) Sky Survey at 3 GHz to achieve our goals. In addition, for one of the restarted candidates, we present new dedicated observations with the VLA at 3 GHz. Results. We characterised the central regions of the radio galaxies in our sample and found various morphologies, some even mimicking well-known double-double radio galaxies but on a smaller scale, that is, a few tens of kiloparsecs for the size of the restarted activity. We also see the beginnings of active jets or distinct detections unrelated to the large-scale structure. Furthermore, we found a variety of radio spectra characterising the sources in our sample, such as flat, steep, or peaked in the frequency range between 150 MHz and 3 GHz, indicative of the different life-cycle phases of the sources in our sample. Based on these analyses, we confirm five out of six previously considered restarted candidates and identify three more restarted candidates from the active sample. As the number of restarted candidates still exceeds that of remnant candidates, this is consistent with previous results suggesting that the restarted phase can occur after a relatively short remnant phase (i.e. a few tens of millions of years).

Relativistic Jet Motion in the Radio-quiet LINER Galaxy KISSR 872

We report superluminal jet motion with an apparent speed of β app = 1.65 ± 0.57 in the radio-quiet (RQ) low-ionization nuclear emission-line region (LINER) galaxy KISSR 872. This result comes from two-epoch phase-referenced very long baseline interferometry observations at 5 GHz. The detection of bulk relativistic motion in the jet of this extremely radio-faint active galactic nucleus (AGN), with a total 1.4 GHz flux density of 5 mJy in the 5.″4 resolution Very Large Array FIRST survey image and 1.5 mJy in the ∼5 mas resolution Very Long Baseline Array image, is the first of its kind in an RQ LINER galaxy. The presence of relativistic jets in lower accretion rate objects like KISSR 872, with an Eddington ratio of 0.04, reveals that even RQ AGN can harbor relativistic jets and provides evidence of their universality over a wide range of accretion powers.

Study of star formation in dual nuclei galaxies using UVIT observations

ABSTRACT We have used the Ultraviolet Imaging Telescope (UVIT) aboard AstroSat to study star formation in a sample of nine dual nuclei galaxies with separations ⪅ 11 kpc, which is an expected outcome of galaxy mergers. To minimize the contribution of active galactic nuclei (AGN) emission, we have used mid-IR colour cut-offs and masked the AGN-dominated nuclei. The UV continuum slope (β) is used to calculate the internal extinction (AV) which ranges from 0.53 to 4.04 in the FUV band and 0.44 to 3.10 in the NUV band for the sample. We have detected 1−20 star-forming clumps in our sample galaxies. The extinction-corrected total FUV star formation rate (SFR) ranges from ∼0.35 to ∼32 M⊙ yr−1. Our analyses of AV, specific SFR (sSFR) show that dual nuclei sources are associated with dusty, star-forming galaxies. The FUV − NUV colour maps show redder colour in the nuclear and disc regions while bluer colour is observed in the outskirts of most galaxies which can be due to embedded dust or different stellar populations. We have found some signatures of possible stellar/AGN feedback like a ring of star formation, a redder ring around blue nuclei, etc. However, further observations are required to confirm this.

Morphological and phylogenetic resolution of Conoideocrella luteorostrata (Hypocreales: Clavicipitaceae), a potential biocontrol fungus for Fiorinia externa in United States Christmas tree production areas

ABSTRACT The entomopathogenic fungus Conoideocrella luteorostrata has recently been implicated in natural epizootics among exotic elongate hemlock scale (EHS) insects in Christmas tree farms in the eastern United States. Since 1913, C. luteorostrata has been reported from various plant feeding Hemiptera in the southeastern United States, but comprehensive morphological and phylogenetic studies of U.S. populations are lacking. The recovery of multiple strains of C. luteorostrata from mycosed EHS in North Carolina provided an opportunity to conduct pathogenicity assays and morphological and phylogenetic studies to investigate genus- and species-level boundaries among the Clavicipitaceae. Pathogenicity assays confirmed that C. luteorostrata causes mortality of EHS crawlers, an essential first step in developing this fungus as a biocontrol. Morphological studies revealed that conidia aligned with previous measurements of the Paecilomyces-like asexual state of C. luteorostrata, with conidiophore morphology consistent with historical observations. Additionally, a Hirsutella-like synanamorph was observed in select C. luteorostrata strains. In both a four-locus, 54-taxon Clavicipitaceae-wide phylogenetic analysis including D1–D2 domains of the nuclear 28S rRNA region (28S), elongation factor 1 alpha (EF1-α), DNA-directed RNA polymerase II subunit 1 (RPB1), and DNA-directed RNA polymerase II subunit 2 (RPB2) and a two-locus, 38-taxon (28S and EF1-α) phylogenetic analysis, all three Conoideocrella species were resolved as strongly supported monophyletic lineages across all loci and both methods (maximum likelihood and Bayesian inference) of phylogenetic inference except for 28S for C. tenuis. Despite the strong support for individual Conoideocrella species, none of the analyses supported the monophyly of Conoideocrella with the inclusion of Dussiella. Due to the paucity of RPB1 and RPB2 sequence data, EF1-α provided superior delimitation of intraspecies groupings for Conoideocrella and should be used in future studies. Further development of C. luteorostrata as a biocontrol against EHS will require additional surveys across diverse Hemiptera and expanded pathogenicity testing to clarify host range and efficacy of this fungus.

The use of the 5S rDNA IGS region for DNA barcoding and molecular taxonomy of two Ukrainian species of the genus Tulipa L.

Taxonomic identification of closely related representatives of the genus Tulipa L. is complicated by the convergent similarity of morphological characters, interspecific hybridization, polyploidy and asexual reproduction. Among the tulips in the flora of Ukraine, the most problematic is the status of taxa of the complex species T. sylvestris L. Aim. To examine the organization and evolution of the nuclear 5S rDNA IGS region for four closely related Tulipa taxa and to evaluate the possibility of its use in the molecular taxonomy of this plant group. Methods. PCR amplification, cloning and sequencing of 5S rDNA repeat units, bioinformatic and phylogenetic analysis. Results. In this work, 5S rDNA repeats were sequenced for the species T. graniticola and T. ophiophylla, which are considered to be synonyms of T. sylvestris L. by many authors. We also assembled the main ribotypes from full-genome libraries of short Illumina reads for T. patens, and T. saxatilis, the species related to T. sylvestris. A comparative analysis of the structure of 5S rDNA sequences and a phylogenetic analysis based on the IGS region were carried out. Conclusions. A high level of 5S rDNA IGS variability has been demonstrated for representatives of the subgenus Eriostemones of the genus Tulipa. The use of 5S rDNA IGS for phylogenetic analysis enabled the clear delimitation of the closely related species T. saxatilis, T. patens, and the complex species T. sylvestris, as well as the delineation of the taxa with the controversial status, T. graniticola and T. ophiophylla. Therefore, the use of this region of the nuclear genome is a promising approach to the molecular taxonomy of the genus Tulipa.

Active galactic nuclei and gravitational redshifts

Gravitational redshift is a classical effect of General Relativity. It has been measured in stars, quasars, and clusters of galaxies. We identify the signature of gravitational redshift in the emission lines of active galaxies that is caused by supermassive black holes and compare this signature to what is found for inactive galaxies. Using the virial theorem, we estimated gravitational redshifts for quasars from the 14th data release (DR14) of the Sloan Digital Sky Survey (SDSS) and compared them with measured gravitational redshifts from the difference between the redshifts of emission lines of Sydney Australian Astronomical Observatory Multi-object Integral Field (SAMI) galaxies in the central and outer annuli of their integral field spectra. Firstly, from the full width at half maximum of $H_ beta$ lines of 57 Seyfert type I galaxies of the active galactic nucleus (AGN) Black Hole Mass Database, we derive a median gravitational redshift $z_g = 1.18 $. Expanding this analysis to 86755 quasars from DR14 of SDSS, we have a median value $z_g = 1.52 . Then, by comparing the redshifts of lines measured in the central and outer regions of low-ionization nuclear emission-line region galaxies in the SAMI survey, we obtain $z_g = (0.68 which increases to $z_g = (1.0 $ for the $H_ and $H_ lines . These numbers are compatible with central black holes of $ 10^9$ solar masses and broad line regions of $ 1$ pc. For non-AGN galaxies, the gravitational redshift is compatible with zero.

An optimum study on the laser scanning confocal microscopy techniques for BiFC assay using plant protoplast

BackgroundThe bimolecular fluorescence complementation (BiFC) assay is commonly used for investigating protein–protein interactions. While several BiFC detection systems have been developed, there is a limited amount of research focused on using laser scanning confocal microscope (LSCM) techniques to observe protoplasts. Protoplasts are more susceptible to damage and instability compared to their original cell state due to the preparation treatments they undergo, which makes it challenging for researchers to manipulate them during observation under LSCMs. Therefore, it is crucial to utilize microscope techniques properly and efficiently in BiFC assays.ResultsWhen the target fluorescence is weak, the autofluorescence of chloroplast particles in protoplasts can interfere with the detection of BiFC signals localized in the nuclear region. Spectrum analysis revealed that chloroplast autofluorescence can be excited by lasers of various types, with the highest fluorescence signal observed at around 660 nm. Furthermore, our investigation into the impact of different pipette tips on the integrity of protoplast samples indicated that the utilization of cut tips with larger openings can mitigate cell breakage. We presented a workflow of LSCM techniques for investigating protoplast BiFC and discussed the microscopic manipulation involved in sample preparation and image capturing.ConclusionWhen the BiFC signals are weak, they may be affected by chloroplast autofluorescence. However, when used properly, the autofluorescence of chloroplasts can serve as an excellent internal marker for effectively distinguishing other signals. In combination with other findings, this study can provide valuable reference for researchers conducting BiFC assays and related studies.

Millennial-scale variations in Arctic sea ice are recorded in sedimentary ancient DNA of the microalga Polarella glacialis

Sea ice is a critical component of the Earth’s Climate System and a unique habitat. Sea-ice changes prior to the satellite era are poorly documented, and proxy methods are needed to constrain its past variability. Here, we demonstrate the potential of sedimentary DNA from Polarella glacialis, a sea-ice microalga, for tracing past sea-ice conditions. We quantified P. glacialis DNA (targeting the nuclear ribosomal ITS1 region) in Arctic marine and fjord surface sediments and a sediment core from northern Baffin Bay spanning 12,000 years. Sea ice and sediment trap samples confirmed that cysts of P. glacialis are common in first-year sea ice and sinking particulate matter following sea-ice melt. Its detection is more efficient with our molecular approach than standard micropaleontological methods. Given that the species inhabits coastal and marine environments in the Arctic and Antarctic, P. glacialis DNA has the potential to become a useful tool for circum-polar sea-ice reconstructions.

Off-nuclear H2O maser and dense molecular gas in NGC 1068

ABSTRACT The results of high-resolution spectral-line observations of dense molecular gas are presented towards the nuclear region of the type 2 Seyfert galaxy NGC 1068. MERLIN observations of the 22 GHz H2O maser were made for imaging the known off-nuclear maser emission at radio jet component located about 0.3 arcsec north-east of the radio nucleus in the galaxy. High angular resolution ALMA observations have spatially resolved the molecular gas emissions of HCN and HCO+ in this region. The off-nuclear maser spots are found to nearly overlap with a ring-like molecular gas structure and are tracing an evolving shock-like structure, which appears to be energized by interaction between the radio jet and circumnuclear medium. The scenario of the dynamic jet–ISM interaction is further supported by a systematic shift of the centroid velocities of the off-nuclear maser features over a period of 35 yr. The enhanced integrated flux ratios of the HCN to HCO+ line emission features at component C suggest a kinetic temperature Tk ≳ 300 K and an H2 density of ≳ 106 cm−3, which are conditions where water masers may be formed. The diagnostics of the masering action in this jet–ISM interaction region is exemplary for galaxies hosting off-nuclear H2O maser emission.

The role of introgressive hybridization in shaping the geographically isolated gene pools of wax palm populations (genus Ceroxylon)

The speciation continuum is the process by which genetic groups diverge until they reach reproductive isolation. It has become common in the literature to show that this process is gradual and flickering, with possibly many instances of secondary contact and introgression after divergence has started. The level of divergence might vary among genomic regions due to, among others, the different forces and roles of selection played by the shared regions. Through hybrid capture, we sequenced ca. 4,000 nuclear regions in populations of six species of wax palms, five of which form a monophyletic group (genus Ceroxylon, Arecaceae: Ceroxyloideae). We show that in this group, the different populations show varying degrees of introgressive hybridization, and two of them are backcrosses of the other three ‘pure’ species. This is particularly interesting because these three species are dioecious, have a shared main pollinator, and have slightly overlapping reproductive seasons but highly divergent morphologies. Our work supports shows wax palms diverge under positive and background selection in allopatry, and hybridize due to secondary contact and inefficient reproductive barriers, which sustain genetic diversity. Introgressed regions are generally not under positive selection. Peripheral populations are backcrosses of other species; thus, introgressive hybridization is likely modulated by demographic effects rather than selective pressures. In general, these species might function as an ‘evolutionary syngameon’ where expanding, peripheral, small, and isolated populations maintain diversity by crossing with available individuals of other wax palms. In the Andean context, species can benefit from gained variation from a second taxon or the enhancement of population sizes by recreating a common genetic pool.

Scalar Relativistic Effects with Multiwavelets: Implementation and Benchmark.

The importance of relativistic effects in quantum chemistry is widely recognized, not only for heavier elements but throughout the periodic table. At the same time, relativistic effects are strongest in the nuclear region, where the description of electrons through a linear combination of atomic orbitals becomes more challenging. Furthermore, the choice of basis sets for heavier elements is limited compared with lighter elements where precise basis sets are available. Thanks to the framework of multiresolution analysis, multiwavelets provide an appealing alternative to overcoming this challenge: they lead to robust error control and adaptive algorithms that automatically refine the basis set description until the desired precision is reached. This allows one to achieve a proper description of the nuclear region. In this work, we extended the multiwavelet-based code MRChem to the scalar zero-order regular approximation framework. We validated our implementation by comparing the total energies for a small set of elements and molecules. To confirm the validity of our implementation, we compared both against a radial numerical code for atoms and the plane-wave-based code EXCITING.

Dicranum shennongjiaense W.Z.Huang & R.L.Zhu (Dicranaceae, Bryophyta), a new species from Central China supported by morphological and molecular evidence

ABSTRACT Introduction Dicranum Hedw. is one of the most taxonomically challenging genera of mosses, having 93 accepted species worldwide. Although recent integrative taxonomic revisions have clarified the delimitation of most species within this genus, the circumscriptions of some Dicranum species remain unsolved. During our recent survey of Dicranum in China, an intriguing species with an unknown combination of morphological traits was discovered in the Shennongjia National Nature Reserve, Central China. We carried out a study to provide morphological and phylogenetic evidence with which to determine the taxonomic status of this Chinese species. Methods The phylogenetic evidence was obtained through the combined analysis of five loci (rps4–trnT, trnL–trnF, trnH–psbA, rps19–rpl2 and rpoB) and one nuclear region (nrITS1–5.8S–ITS2). Morphological characteristics were investigated by microscopic examination of specimens. Key results and conclusions A new moss species, Dicranum shennongjiaense W.Z.Huang & R.L.Zhu, is described and illustrated based on molecular and morphological evidence. This new species is characterised by its falcate leaves, rectangular and elongated laminal cells with strongly protruding upper angles on the dorsal side in the upper leaf portion, irregularly bistratose laminal cells above the midleaf, one layer of guide cells in the costa, and sharp serrations on the dorsal side of the costa in the upper leaf portion. Additionally, D. baicalense Tubanova, previously known only from Russia, is newly reported for China. A key for identification of the Chinese species of Dicranum sect. Dicranum is provided.

An empirical formula of nuclear <i>β</i>-decay half-lives

Nuclear <i>β</i>-decay half-lives play an important role not only in nuclear physics, but also in astrophysics. The <i>β</i>-decay half-lives of many nuclei involved in the astrophysical rapid neutron-capture (r -process) still cannot be measured experimentally, so the theoretical predictions of nuclear <i>β</i>-decay half-lives are inevitable for r-process studies. Theoretical models for studying the nuclear <i>β</i>-decay half-lives include the empirical formula, the gross theory, the quasiparticle random phase approximation (QRPA), and the shell model. Compared with other theoretical models of <i>β</i>-decay half-lives, the empirical formula has high computational efficiency, and its prediction accuracy can be improved by introducing more and more physical information. In this work, an empirical formula without free parameters is proposed to calculate the nuclear <i>β</i>-decay half-lives based on the Fermi theory of <i>β</i> decay. By including the pairing effect, the shell effect, and the isospin dependence, the newly proposed empirical formula significantly improves the accuracy of predicting the nuclear <i>β</i>-decay half-life. For the nuclei with half-lives less than 1 second, the root-mean-square deviation of the common logarithms of the nuclear <i>β</i>-decay half-life predicted by the new empirical formula from the experimental data decreases to 0.220, which is improved by about 54% compared with that by the empirical formula without free parameters, even better than those by other existing empirical formulas and microscopic QRPA approaches. In the unknown region, the nuclear <i>β</i>-decay half-lives predicted by the new empirical formula are generally shorter than those predicted by the microscopic models in the light nuclear region, while those predicted by the new empirical formula in the heavy nuclear region are generally in agreement with those predicted by the microscopic models. The half-lives of neutron-rich nuclei on the nuclear chart are then predicted by the new empirical formula, providing nuclear <i>β</i>-decay half-life inputs for the r-process simulations.

Morphology, complete mitochondrial genome, and molecular phylogeny of Rhabdias macrocephalum n. sp. (Nematoda: Rhabdiasidae) from Diploderma splendidum (Reptilia: Agamidae).

Species of the genus Rhabdias Stiles & Hassall, 1905 are common parasitic nematodes occurring in the lungs of amphibians and reptiles worldwide. In the present study, Rhabdias macrocephalum n. sp. is described using integrated morphological methods (light and scanning electron microscopy) and molecular approaches (sequencing of the nuclear 28S and ITS regions, and mitochondrial cox1, cox2, and 12S genes) based on specimens collected from the green striped tree dragon Diploderma splendidum (Barbour & Dunn) (Reptilia: Agamidae) in China. The complete mitochondrial genome of R. macrocephalum n. sp. was sequenced and annotated: it is 14,819bp in length, including 12 protein coding genes (missing atp8), 22 tRNA genes, 2 rRNA genes and three non-coding regions. The gene arrangement of R. macrocephalum n. sp. is different from all of the currently available mitogenomes of nematodes and represents a novel type of mitochondrial gene arrangement reported in Nematoda. Molecular phylogenetic results based on the ITS+28S data support the monophyly of Entomelas, Pneumonema, Serpentirhabdias, and Rhabdias, and showed R. macrocephalum n. sp. forming a most basal lineage in Rhabdias.

T-Cell Posttransplant Lymphoproliferative Disorders After Allogeneic Hematopoietic Stem Cell Transplantation: Case Series and Systemic Review.

Posttransplant lymphoproliferative disorder (PTLD) is a rare lymphoid and/or plasmocytic proliferation that occurs after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aimed to identify the pathologic features and clinical outcomes of T-cell PTLD, an extremely rare subtype of PTLD, after allo-HSCT. In this study, six allo-HSCT recipients with T-cell PTLD from five transplant centers in China were enrolled. All the T-cell PTLD were donor-derived, and three patients were with monomorphic and three with polymorphic types, respectively. All patients received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based chemotherapy. Five patients achieved complete response (CR), and one experienced progressive disease (PD). The median time from HSCT to onset was 4 (range: 0.6-72) months, analyzed in combination with the other 16 patients with T-cell PTLD identified from previous reports. About 56.3% of the T-cell samples (9/16) were positive for in situ hybridization with an Epstein-Barr virus (EBV)-encoded small nuclear early region (EBER ISH). CHOP-based chemotherapy might be the optimal strategy for patients who showed no response to empiric therapy with a CR rate of 87.5%. In conclusion, our study observed that T-cell PTLD has distinct clinical manifestations and morphological features, which characterized by less relation to EBV, later occurrence, and poorer prognosis when compared with B-cell PTLD.

WISDOM Project - XVI. The link between circumnuclear molecular gas reservoirs and active galactic nucleus fuelling

ABSTRACT We use high-resolution data from the millimetre-Wave Interferometric Survey of Dark Object Masses (WISDOM) project to investigate the connection between circumnuclear gas reservoirs and nuclear activity in a sample of nearby galaxies. Our sample spans a wide range of nuclear activity types including radio galaxies, Seyfert galaxies, low-luminosity active galactic nuclei (AGN) and inactive galaxies. We use measurements of nuclear millimetre continuum emission along with other archival tracers of AGN accretion/activity to investigate previous claims that at, circumnuclear scales (<100 pc), these should correlate with the mass of the cold molecular gas. We find that the molecular gas mass does not correlate with any tracer of nuclear activity. This suggests the level of nuclear activity cannot solely be regulated by the amount of cold gas around the supermassive black hole (SMBH). This indicates that AGN fuelling, that drives gas from the large-scale galaxy to the nuclear regions, is not a ubiquitous process and may vary between AGN type, with time-scale variations likely to be very important. By studying the structure of the central molecular gas reservoirs, we find our galaxies have a range of nuclear molecular gas concentrations. This could indicate that some of our galaxies may have had their circumnuclear regions impacted by AGN feedback, even though they currently have low nuclear activity. Alternatively, the nuclear molecular gas concentrations in our galaxies could instead be set by secular processes.

White Blood Cell Type Detection Using K-means Clustering and Multicolor Spaces

The white blood cell (WBC) plays an instrumental role in protecting the human body from different infectious diseases and unknown biological invaders. Their count and cellular morphology drastically change when the body suffers from any such disease or abnormal conditions. This paper demonstrates the detection of five types of WBC present in human blood smear images. Several authors proposed WBC detection using only one color space. But this paper addresses WBC-type detection using four popular color spaces – RGB (red, green, and blue), HSV (hue, saturation, and intensity), YCbCr (luminance, chroma blue, and chroma red), and L*a*b* (luminosity, chromaticity layer “a*”, and chromaticity layer “b*”). The proposed methodology involves color thresholding, K-means clustering, nuclear region analysis, and the implementation of a feedforward neural network. The unsupervised machine learning algorithm, K-means clustering is used to segment nuclei from the blood smear images. The detection of WBC-type using four color spaces is compared in terms of accuracy, sensitivity, specificity, and positive predictive value. It is observed that HSV-based WBC-type detection methodology outperforms methodologies based on RGB, YCbCr, and L*a*b* color spaces. The same methodology mentioned above is then compared with the works proposed by other authors.

Population Structure and Genetic Diversity Analyses Provide New Insight into the Endemic Species Aster spathulifolius Maxim. and Its Evolutionary History.

Aster spathulifolius, an ecologically significant plant species native to the coastal regions of Korea and Japan, remains understudied in terms of its genetic structure and evolutionary history. In this study, we employed four chloroplast markers and the nuclear ITS region from 15 populations of A. spathulifolius from both Korea and Japan, including their islands, to unravel the spatial genetic structure, differentiation, gene flow, phylogenetic, and biogeographical relationships. Analysis based on multiple methods identified a low level of genetic diversity, genetic differentiation and gene flow among A. spathulifolius populations. Network analysis and principal coordinates analysis showed that 15 populations could be divided into two groups: mainland and island. Furthermore, UPGMA, neighbor-net, maximum-likelihood and Bayesian inference-based phylogenetic tree confirmed that these populations formed two distinct clades. Therefore, the island populations might be treated as A. spathulifolius populations rather than A. oharai populations. Divergence time analysis estimated the divergence of A. spathulifolius lineages approximately 23.09 million years ago, while ancestral area reconstruction analysis suggested Korea as the potential origin, conflicting with alternative scenarios. These findings contribute to a comprehensive understanding of the evolutionary history, genetic structure, and adaptive strategies of A. spathulifolius in coastal environments. Our study challenges previous assumptions and underscores the necessity for further population studies to elucidate the intricate dynamics of this distinctive plant species.