bluuebunny/crossref_metadata_2025_split huggingface dataset:
A MARKOV PROCESS OF GENE FREQUENCY CHANGE IN A GEOGRAPHICALLY STRUCTURED POPULATION
Authors: Maruyama Takeo 
Published: January 2021

ABSTRACT
A Markov process (chain) of gene frequency change is derived for a geographically-structured model of a population. The population consists of colonies which are connected by migration. Selection operates in each colony independently. It is shown that there exists a stochastic clock that transforms the originally complicated process of gene frequency change to a random walk which is independent of the geographical structure of the population. The time parameter is a local random time that is dependent on the sample path. In fact, if the alleles are selectively neutral, the time parameter is exactly equal to the sum of the average local genetic variation appearing in the population, and otherwise they are approximately equal. The Kolmogorov forward and backward equations of the process are obtained. As a limit of large population size, a diffusion process is derived. The transition probabilities of the Markov chain and of the diffusion process are obtained explicitly. Certain quantities of biological interest are shown to be independent of the population structure. The quantities are the fixation probability of a mutant, the sum of the average local genetic variation and the variation summed over the generations in which the gene frequency in the whole population assumes a specified value.
ON RECOMBINATION-DEFECTIVE MEIOTIC MUTANTS IN DROSOPHILA MELANOGASTER
Authors: Carpenter Adelaide T C , Sandler L 
Published: January 2021

ABSTRACT
The genetic effects of four recombination-defective meiotic mutants in D. melanogaster on recombination, segregation and the relationship between the two have been examined. The results suggest the following. (1) The anomalous meiotic segregation observed in females carrying recombination-defective meiotic mutants is a normal consequence of the reduction in exchange; each recombination-defective mutant can, therefore, be defined by a single lesion in the control of recombination. (2) Of the operations used to date to characterize this lesion, the most informative is whether the decrease in recombination is uniform along the chromosome arm or nonuniform; in particular, if the formation of recombinants is visualized as a two-step process consisting of the establishment of possible exchange points (exchange preconditions) followed by exchange itself, then mutants that uniformly decrease crossing over involve defects in the second step while mutants that result in a nonuniform decrease involve defects in the establishment of exchange preconditions. (3) Of the fourteen loci identified by recombination-defective meiotic mutants, only one (with two alleles) is involved in exchange itself; the others all reduce recombination most drastically in distal regions, suggesting that the establishment of exchange preconditions involves polar processes. (4) A very general description of the polar establishment of exchange preconditions is presented; this description has the property that if a precondition meiotic mutant affects interference, the coefficient of coincidence will be increased in proportion to the decrease in recombination which is what is observed for all recombination-defective meiotic mutants studied to date.
A COLD-SENSITIVE ZYGOTIC LETHAL CAUSING HIGH FREQUENCIES OF NONDISJUNCTION DURING MEIOSIS I IN DROSOPHILA MELANOGASTER FEMALES
Authors: Wright Theodore R F 
Published: January 2021

ABSTRACT
The X-linked, cold-sensitive zygotic lethal, l(1)TW-6cs, both in homozygous and heterozygous females, induces nondisjunction of all four chromosomes at Meiosis I at both 25° and 17°. Nondisjunction frequencies approaching 0.5 for the X and fourth chromosomes have been observed at 16°–18°. The disjunction of the X chromosomes in males is not affected. The mutant causes mitotic irregularities in zygotes at both 25° and 17°. Mortality of all zygotes produced by the crosses 6cs/6cs × 6cs/BsY and FM7/6cs × 6cs/BsY is respectively 86% and 67–74% at 25° and 99.8–99.9% and 94% at 17°. The mortality of 6cs hemizygotes derived from females carrying no doses of 6cs (C(1)DX,y f/y × 6cs/BsY) is 45–55% at 25° and 98% at 17°. The length of the temperature-sensitive period for 6cs homo- and hemizygotes is affected by the maternal dosage of 6cs; the shortest TSP is for zero and the longest is for two maternal doses. Mortality takes place primarily during embryogenesis with some larval and little pupal mortality. Analysis of sectioned embryos indicates that the large array of different patterns of damage observed could have arisen from abnormal cleavage divisions and the incomplete population of the blastoderm with nuclei.
SELECTION FOR BLOOD PRESSURE LEVELS IN MICE
Authors: Schlager Gunther 
Published: January 2021

ABSTRACT
Response to two-way selection for systolic blood pressure was immediate and continuous for about eight generations. In the twelfth generation, the High males differed from the Low males by 38 mmHG; the females differed by 39 mmHg. There was little overlap between the two lines and they were statistically significant from each other and from the Random control line. There appeared to be no more additive genetic variance in the eleventh and twelfth generations. Causes for the cessation of response are explored. This is probably due to a combination of natural selection acting to reduce litter sizes in the Low line, a higher incidence of sudden deaths in the High line, and loss of favorable alleles as both selection lines went through a population bottleneck in the ninth generation.—In the eleventh generation, the selected lines were used to produce F1, F2, and backcross generations. A genetic analysis yielded significant additive and dominance components in the inheritance of systolic blood pressure.
LIKELIHOOD ANALYSIS OF RECOMBINATIONAL DISEQUILIBRIUM IN MULTIPLE-LOCUS GAMETIC FREQUENCIES
Authors: Smouse Peter E 
Published: January 2021

ABSTRACT
Likelihood methods are developed for the estimation and testing of multiple-locus gametic disequilibria, using log-linear models of parametric effects. The estimates of disquilibrium are related to Kimura's Z-measure, and may be extended to multiple alleles and multiple loci. Likelihood ratio test criteria are constructed, which are asymptotically distributed as χ2. The analysis is partitioned into various components corresponding to two-locus, residual three-locus, and higher order disequilibria. A four-locus example from Hordeum vulgare L. is utilized to illustrate the analysis. Most of the multiple-locus disequilibrium is accounted for by two-locus effects, and closely linked loci show considerably more disequilibrium than unlinked loci. It is shown that all possible pairwise comparisons are not statistically independent.
COVARIANCES BETWEEN ARBITRARY RELATIVES IN AUTOTETRAPLOIDS WITH PANMICTIC DISEQUILIBRIUM
Authors: Gallais A 
Published: January 2021

ABSTRACT
In random mating autopolyploid populations which have not reached equilibrium, two alleles may be interdependent as a result of the phenomenon of gametic recombination, i.e. the maintenance through successive gamete generations of an association of two alleles from the same gamete in a source reference generation. Any two alleles are dependent by this relationship if they derive by descent from the same ancestral gamete in the source population. Applied with the classical notion of identity by descent, the concept thus defined identifies new coefficients of dependence between arbitrary relatives. Coefficients of dependence are probabilities attached to the drawing of genes from two zygotes such that there are certain relationships amongst them. Applying the concept to autotetraploids, consideration of the states of dependence between the genes of a zygote or of a pair of zygotes leads to the definition of new parameters bearing on population means, variances and covariances, for arbitrary inbreeding. The absence of epistasis is supposed. Some applications of interest in artificial selection are briefly envisaged, with simplifying restrictions on genetic effects. The particular case of diallelism is also considered.
A new duck genome reveals conserved and convergently evolved chromosome architectures of birds and mammals
Authors: Li Jing , Zhang Jilin , Liu Jing , Zhou Yang , Cai Cheng , Xu Luohao , Dai Xuelei , Feng Shaohong , Guo Chunxue , Rao Jinpeng , Wei Kai , Jarvis Erich D , Jiang Yu , Zhou Zhengkui , Zhang Guojie , Zhou Qi 
Published: January 2021

Abstract

Background
Ducks have a typical avian karyotype that consists of macro- and microchromosomes, but a pair of much less differentiated ZW sex chromosomes compared to chickens. To elucidate the evolution of chromosome architectures between ducks and chickens, and between birds and mammals, we produced a nearly complete chromosomal assembly of a female Pekin duck by combining long-read sequencing and multiplatform scaffolding techniques.

Results
A major improvement of genome assembly and annotation quality resulted from the successful resolution of lineage-specific propagated repeats that fragmented the previous Illumina-based assembly. We found that the duck topologically associated domains (TAD) are demarcated by putative binding sites of the insulator protein CTCF, housekeeping genes, or transitions of active/inactive chromatin compartments, indicating conserved mechanisms of spatial chromosome folding with mammals. There are extensive overlaps of TAD boundaries between duck and chicken, and also between the TAD boundaries and chromosome inversion breakpoints. This suggests strong natural selection pressure on maintaining regulatory domain integrity, or vulnerability of TAD boundaries to DNA double-strand breaks. The duck W chromosome retains 2.5-fold more genes relative to chicken. Similar to the independently evolved human Y chromosome, the duck W evolved massive dispersed palindromic structures, and a pattern of sequence divergence with the Z chromosome that reflects stepwise suppression of homologous recombination.

Conclusions
Our results provide novel insights into the conserved and convergently evolved chromosome features of birds and mammals, and also importantly add to the genomic resources for poultry studies.
Differentiation of glioblastoma stem cells promoted by miR-128 or miR-302a overexpression enhances senescence-associated cytotoxicity of axitinib
Authors: Cardoso Ana M , Morais Catarina M , Pena Frederico , Marante Tânia , Cunha Pedro P , Jurado Amália S , Pedroso de Lima Maria C 
Published: January 2021

Abstract
Despite the intense global efforts towards an effective treatment of glioblastoma (GB), current therapeutic options are unsatisfactory with a median survival time of 12–15 months after diagnosis, which has not improved significantly over more than a decade. The high tumoral heterogeneity confers resistance to therapies, which has hindered a successful clinical outcome, GB remaining among the deadliest cancers. A hallmark of GB is its high recurrence rate, which has been attributed to the presence of a small subpopulation of tumor cells called GB stem-like cells (GSC). In the present work, the efficacy of a multimodal strategy combining microRNA (miRNA) modulation with new generation multitargeted tyrosine kinase inhibitors (imatinib and axitinib) was investigated aiming at tackling this subpopulation of GB cells. MiR-128 and miR-302a were selected as attractive therapeutic candidates on the basis of previous findings reporting that reestablishment of their decreased expression levels in GSC resulted in cell differentiation, which could represent a possible strategy to sensitize GSC to chemotherapy. Our results show that overexpression of miR-128 or miR-302a induced GSC differentiation, which enhanced senescence mediated by axitinib treatment, thus further impairing GSC proliferation. We also provided evidence for the capacity of GSC to efficiently internalize functionalized stable nucleic acid lipid particles, previously developed and successfully applied in our laboratory to target GB. Taken together, our findings will be important in the future design of a GB-targeted multimodal miRNA-based gene therapy, combining overexpression of miR-128 or miR-302a with axitinib treatment, endowed with the ability to overcome drug resistance.
Biological Activity of trans-2-Hexenal Against the Storage Insect Pest Tribolium castaneum (Coleoptera: Tenebrionidae) and Mycotoxigenic Storage Fungi
Authors: Cui Kaidi , He Leiming , Cui Guangrui , Zhang Tao , Chen Yue , Zhang Tao , Mu Wei , Liu Feng 
Published: January 2021

Abstract
Grain commodities in postharvest storage often deteriorate because of fungal and insect attacks. With the green consumption requirements of consumers, ecofriendly and safe pesticides are needed for grain storage. The current study investigated the efficacy of the plant volatile compound trans-2-hexenal against the storage insect pest Tribolium castaneum (Herbst) and three commonly occurring storage fungi, viz., Fusarium graminearum, Aspergillus flavus, and Aspergillus niger, to recommend its application as a botanical fumigant for grain commodities. trans-2-Hexenal weakly repels T. castaneum but has favorable insecticidal activity against multiple developmental stages of T. castaneum, ranging in sensitivity as follows: eggs (LC50 = 14.3 µl/l) &gt; adults (31.6 µl/l) &gt; young larvae (42.1 µl/l) &gt; mature larvae (64.5 µl/l) &gt; pupae (70.5 µl/l). Moreover, trans-2-hexenal caused a high malformation rate and high mortality in adults developed from fumigated pupae. In a 7-d grain, trans-2-hexenal at 0.8 µl/ml provided an appreciable efficacy (81.3%), and concentrations ≥ 0.1 µl/ml completely inhibited the offspring of T. castaneum. trans-2-Hexenal was nonphytotoxic to the seed germination and seedling growth of wheat seeds. Furthermore, trans-2-hexenal completely inhibited the growth of A. flavus, F. graminearum, and A. niger at 5, 10, and 10 µl/l, respectively. The favorable biological activity of trans-2-hexenal against T. castaneum and three frequently occurring mycotoxigenic storage fungi indicated the potential of trans-2-hexenal for simultaneously controlling pests and pathogens, which could reduce its application frequency in grains and decrease pesticide resistance risks.
OIP5-AS1 specifies p53-driven POX transcription regulated by TRPC6 in glioma
Authors: Shao Wei , Hao Zhen-Yu , Chen Yi-Fei , Du Jun , He Qian , Ren Liang-Liang , Gao Yan , Song Nan , Song Yan , He Hua , Wang Yi-Zheng 
Published: January 2021

Abstract
Transcription factors (TFs) control an array of expressed genes. However, the specifics of how a gene is expressed in time and space as controlled by a TF remain largely unknown. Here, in TRPC6-regulated proline oxidase 1 (POX) transcription in human glioma, we report that OIP5-AS1, a long noncoding RNA, determines the specificity of p53-driven POX expression. The OIP5-AS1/p53 complex via its 24 nucleotides binds to the POX promoter and is necessary for POX expression but not for p21 transcription. An O-site in the POX promoter to which OIP5-AS1 binds was identified that is required for OIP5-AS1/p53 binding and POX transcription. Blocking OIP5-AS1 binding to the O-site inhibits POX transcription and promotes glioma development. Thus, the OIP5-AS1/O-site module decides p53-controlled POX expression as regulated by TRPC6 and affects glioma development.
A celestial matryoshka: dynamical and spectroscopic analysis of the Albireo system
Authors: Drimmel Ronald , Sozzetti Alessandro , Schröder Klaus-Peter , Bastian Ulrich , Pinamonti Matteo , Jack Dennis , Hernández Huerta Missael A 
Published: January 2021

ABSTRACT
We present a spectroscopic characterization and a new orbital solution for the binary system  β Cyg Aa/Ac (MCA 55), the primary component ( β Cyg A) of the well-known wide double star Albireo. By matching evolutionary tracks to the physical parameters of all three Albireo stars ( β Cyg Aa, Ac, and B) as obtained from a spectroscopic analysis of TIGRE and IUE spectra, we confirm that they are likely coeval. Our final orbit solution is based on radial-velocity measurements taken over a baseline exceeding 120 yr, combined with relative astrometry from speckle interferometric observations and the absolute astrometry from the Hipparcos and Gaia missions. Our final orbit solution has a period of 121.65$^{+3.34}_{-2.90}$ yr with an eccentricity of 0.20$^{+0.01}_{-0.02}$. Thanks to the inclusion of the absolute astrometry, we find a mass ratio of $q = 1.25^{+0.19}_{-0.17}$, and a total mass of $9.47_{-3.24}^{+5.88}$ M⊙, indicating that the secondary (Ac) is the more massive of the pair. These results strongly suggest the presence of a fourth, unseen, member of the Albireo system. Given the current photometric data, it is likely that  β Cyg A is itself a hierarchical triple. We also derive the systemic proper motion, line-of-sight velocity, and an orbital parallax of the  β Cyg A system, allowing us to quantitatively assess the hypothesis that Albireo A and B form a physically bound and genealogically connected system. Finally, we find four potential members of a common proper motion group with Albireo, though none anywhere as close by as the Albireo components A to B.
Radiative mixing layers: insights from turbulent combustion
Authors: Tan Brent , Oh S Peng , Gronke Max 
Published: January 2021

ABSTRACTRadiative mixing layers arise wherever multiphase gas, shear, and radiative cooling are present. Simulations show that in steady state, thermal advection from the hot phase balances radiative cooling. However, many features are puzzling. For instance, hot gas entrainment appears to be numerically converged despite the scale-free, fractal structure of such fronts being unresolved. Additionally, the hot gas heat flux has a characteristic velocity vin ≈ cs, cold(tcool/tsc, cold)−1/4 whose strength and scaling are not intuitive. We revisit these issues in 1D and 3D hydrodynamic simulations. We find that over-cooling only happens if numerical diffusion dominates thermal transport; convergence is still possible even when the Field length is unresolved. A deeper physical understanding of radiative fronts can be obtained by exploiting parallels between mixing layers and turbulent combustion, which has well-developed theory and abundant experimental data. A key parameter is the Damköhler number Da = τturb/tcool, the ratio of the outer eddy turnover time to the cooling time. Once Da &gt; 1, the front fragments into a multiphase medium. Just as for scalar mixing, the eddy turnover time sets the mixing rate, independent of small scale diffusion. For this reason, thermal conduction often has limited impact. We show that vin and the effective emissivity can be understood in detail by adapting combustion theory scalings. Mean density and temperature profiles can also be reproduced remarkably well by mixing length theory. These results have implications for the structure and survival of cold gas in many settings, and resolution requirements for large scale galaxy simulations.
PHANGS–HST: star cluster spectral energy distribution fitting with cigale
Authors: Turner Jordan A , Dale Daniel A , Lee Janice C , Boquien Médéric , Chandar Rupali , Deger Sinan , Larson Kirsten L , Mok Angus , Thilker David A , Ubeda Leonardo , Whitmore Bradley C , Belfiore Francesco , Bigiel Frank , Blanc Guillermo A , Emsellem Eric , Grasha Kathryn , Groves Brent , Klessen Ralf S , Kreckel Kathryn , Kruijssen J M Diederik , Leroy Adam K , Rosolowsky Erik , Sanchez-Blazquez Patricia , Schinnerer Eva , Schruba Andreas , Van Dyk Schuyler D , Williams Thomas G 
Published: January 2021

ABSTRACT
The sensitivity and angular resolution of photometric surveys executed by the Hubble Space Telescope (HST) enable studies of individual star clusters in galaxies out to a few tens of megaparsecs. The fitting of spectral energy distributions (SEDs) of star clusters is essential for measuring their physical properties and studying their evolution. We report on the use of the publicly available Code Investigating GALaxy Emission (cigale) SED fitting package to derive ages, stellar masses, and reddenings for star clusters identified in the Physics at High Angular resolution in Nearby GalaxieS–HST (PHANGS–HST) survey. Using samples of star clusters in the galaxy NGC 3351, we present results of benchmark analyses performed to validate the code and a comparison to SED fitting results from the Legacy Extragalactic Ultraviolet Survey. We consider procedures for the PHANGS–HST SED fitting pipeline, e.g. the choice of single stellar population models, the treatment of nebular emission and dust, and the use of fluxes versus magnitudes for the SED fitting. We report on the properties of clusters in NGC 3351 and find, on average, the clusters residing in the inner star-forming ring of NGC 3351 are young (&lt;10 Myr) and massive (105 M⊙) while clusters in the stellar bulge are significantly older. Cluster mass function fits yield β values around −2, consistent with prior results with a tendency to be shallower at the youngest ages. Finally, we explore a Bayesian analysis with additional physically motivated priors for the distribution of ages and masses and analyse the resulting cluster distributions.
Atmospheric circulation of brown dwarfs and directly imaged exoplanets driven by cloud radiative feedback: effects of rotation
Authors: Tan Xianyu , Showman Adam P 
Published: January 2021

ABSTRACT
Observations of brown dwarfs (BDs), free-floating planetary-mass objects, and directly imaged extrasolar giant planets (EGPs) exhibit rich evidence of large-scale weather. Cloud radiative feedback has been proposed as a potential mechanism driving the vigorous atmospheric circulation on BDs and directly imaged EGPs, and yet it has not been demonstrated in three-dimensional dynamical models at relevant conditions. Here, we present a series of atmospheric circulation models that self-consistently couple dynamics with idealized cloud formation and its radiative effects. We demonstrate that vigorous atmospheric circulation can be triggered and self-maintained by cloud radiative feedback. Typical isobaric temperature variation could reach over 100 K and horizontally averaged wind speed could be several hundreds of $\, {\rm m\, s^{-1}}$. The circulation is dominated by cloud-forming and clear-sky vortices that evolve over time-scales from several to tens of hours. The typical horizontal length-scale of dominant vortices is closed to the Rossby deformation radius, showing a linear dependence on the inverse of rotation rate. Stronger rotation tends to weaken vertical transport of vapour and clouds, leading to overall thinner clouds. Domain-mean outgoing radiative flux exhibits variability over time-scales of tens of hours due to the statistical evolution of storms. Different bottom boundary conditions in the models could lead to qualitatively different circulation near the observable layer. The circulation driven by cloud radiative feedback represents a robust mechanism generating significant surface inhomogeneity as well as irregular flux time variability. Our results have important implications for near-infrared (IR) colours of dusty BDs and EGPs, including the scatter in the near-IR colour–magnitude diagram and the viewing-geometry-dependent near-IR colours.