Higher-level relationships within, and the root of Placentalia, remain contentious issues. Resolution of the placental tree is important to the choice of mammalian genome projects and model ...organisms, as well as for understanding the biogeography of the eutherian radiation. We present phylogenetic analyses of 63 species representing all extant eutherian mammal orders for a new molecular phylogenetic marker, a 1.3
kb portion of exon 26 of the apolipoprotein B (APOB) gene. In addition, we analyzed a multigene concatenation that included APOB sequences and a previously published data set (
Murphy et al., 2001b) of three mitochondrial and 19 nuclear genes, resulting in an alignment of over 17
kb for 42 placentals and two marsupials. Due to computational difficulties, previous maximum likelihood analyses of large, multigene concatenations for placental mammals have used quartet puzzling, less complex models of sequence evolution, or phylogenetic constraints to approximate a full maximum likelihood bootstrap. Here, we utilize a Unix load sharing facility to perform maximum likelihood bootstrap analyses for both the APOB and concatenated data sets with a GTR
+
Γ
+
I model of sequence evolution, tree-bisection and reconnection branch-swapping, and no phylogenetic constraints. Maximum likelihood and Bayesian analyses of both data sets provide support for the superordinal clades Boreoeutheria, Euarchontoglires, Laurasiatheria, Xenarthra, Afrotheria, and Ostentoria (pangolins
+
carnivores), as well as for the monophyly of the orders Eulipotyphla, Primates, and Rodentia, all of which have recently been questioned. Both data sets recovered an association of Hippopotamidae and Cetacea within Cetartiodactyla, as well as hedgehog and shrew within Eulipotyphla. APOB showed strong support for an association of tarsier and Anthropoidea within Primates. Parsimony, maximum likelihood and Bayesian analyses with both data sets placed Afrotheria at the base of the placental radiation. Statistical tests that employed APOB to examine a priori hypotheses for the root of the placental tree rejected rooting on myomorphs and hedgehog, but did not discriminate between rooting at the base of Afrotheria, at the base of Xenarthra, or between Atlantogenata (Xenarthra
+
Afrotheria) and Boreoeutheria. An orthologous deletion of 363
bp in the aligned APOB sequences proved phylogenetically informative for the grouping of the order Carnivora with the order Pholidota into the superordinal clade Ostentoria. A smaller deletion of 237–246
bp was diagnostic of the superordinal clade Afrotheria.
Astrophysical neutrinos are excellent probes of astroparticle physics and high-energy physics. With energies far beyond solar, supernovae, atmospheric, and accelerator neutrinos, high-energy and ...ultra-high-energy neutrinos probe fundamental physics from the TeV scale to the EeV scale and beyond. They are sensitive to physics both within and beyond the Standard Model through their production mechanisms and in their propagation over cosmological distances. They carry unique information about their extreme non-thermal sources by giving insight into regions that are opaque to electromagnetic radiation. This white paper describes the opportunities astrophysical neutrino observations offer for astrophysics and high-energy physics, today and in coming years.
Potato (Solanum tuberosum L.) is grown in over 100 countries throughout the world. As a staple food, potato is the fourth most important crop after rice, wheat, and maize, and has historically ...contributed to food and nutrition security in the world. Global interest in potato increased recently as world food prices soared, threatening the global food security and stability. Unlike major cereals, potato is not a globally traded commodity, and prices are usually determined by local production costs. Thus, potato is increasingly regarded as a vital food-security crop and as a substitute for costly cereal imports. With such importance, the 29 chapters in the edited book address the issues of sustainable potato production. This book begins with an introduction on sustainable potato production and global food security, and then presents eight case studies selected globally and covering different issues relevant to sustainable potato production in both developed and developing countries.
The High Altitude Water Cherenkov (HAWC) Observatory is a wide-field-of-view gamma-ray observatory that is optimized to detect gamma rays between 300 GeV and several hundred TeV. The HAWC ...Collaboration recently released their third source catalog (3HWC), which contains 65 sources. One of these sources, the ultra-high-energy gamma-ray source 3HWC J1908+063, may exhibit a hardening of the spectral index at the highest energies (above 56 TeV). At least two populations of particles are needed to satisfactorily explain the highest energy emission. This second component could be leptonic or hadronic in origin. If it is hadronic in origin, it would imply the presence of protons with energies up to ~1 PeV near the source. We have searched other 3HWC sources for the presence of this spectral hardening feature. If observed, this would imply that the sources could make good PeVatron candidates.
The Ultra-High-Energy Source MGRO J1908+06 Malone, Kelly; Abeysekara, Anushka Udara; Albert, Andrea ...
Pos : proceedings of science,
07/2021, Letnik:
395
Journal Article
Recenzirano
Odprti dostop
The TeV gamma-ray source MGRO J1908+06 is one of the highest-energy sources known, with observed emission by the High Altitude Water Cherenkov (HAWC) Observatory extending well past 100 TeV. The ...source exhibits both energy-dependent morphology and a spatially-dependent spectral index. The emission is likely to be dominantly leptonic, and associated with the radio-quiet PSR J1907+0602. However, one-population models do not describe the data well; a second particle population is needed to explain the shape of the spectral energy distribution at the highest energies. This component can be well-described by either leptonic or hadronic hypotheses. We discuss this feature and implications for detection by multi-wavelength and multi-messenger experiments.
A search for decays of the B
c meson was performed using data collected from 1990–1995 with the OPAL detector on or near the Z
0 peak at LEP. The decay channels B
c
+→J/
ψπ
+, B
c
+→J/
ψa
1
+ and B
c
...+→J/
ψℓ
+
ν were investigated, where ℓ denotes an electron or a muon. Two candidates are observed in the mode B
c
+→J/
ψπ
+, with an estimated background of (0.63±0.20) events. The weighted mean of the masses of the two candidates is (6.32±0.06) GeV/
c
2, which is consistent with the predicted mass of the B
c meson. One candidate event is observed in the mode B
c
+→J/
ψℓ
+
ν, with an estimated background of (0.82±0.19) events. No candidate events are observed in the B
c
+→J/
ψa
1
+ decay mode, with an estimated background of (1.10±0.22) events. Upper bounds at the 90% confidence level are set on the production rates for these processes.
Soybean (Glycine max) is a self-pollinating species that has relatively low nucleotide polymorphism rates compared with other crop species. Despite the low rate of nucleotide polymorphisms, a wide ...range of heritable phenotypic variation exists. There is even evidence for heritable phenotypic variation among individuals within some cultivars. Williams 82, the soybean cultivar used to produce the reference genome sequence, was derived from backcrossing a Phytophthora root rot resistance locus from the donor parent Kingwa into the recurrent parent Williams. To explore the genetic basis of intracultivar variation, we investigated the nucleotide, structural, and gene content variation of different Williams 82 individuals. Williams 82 individuals exhibited variation in the number and size of introgressed Kingwa loci. In these regions of genomic heterogeneity, the reference Williams 82 genome sequence consists of a mosaic of Williams and Kingwa haplotypes. Genomic structural variation between Williams and Kingwa was maintained between the Williams 82 individuals within the regions of heterogeneity. Additionally, the regions of heterogeneity exhibited gene content differences between Williams 82 individuals. These findings show that genetic heterogeneity in Williams 82 primarily originated from the differential segregation of polymorphic chromosomal regions following the backcross and single-seed descent generations of the breeding process. We conclude that soybean haplotypes can possess a high rate of structural and gene content variation, and the impact of intracultivar genetic heterogeneity may be significant. This detailed characterization will be useful for interpreting soybean genomic data sets and highlights important considerations for research communities that are developing or utilizing a reference genome sequence.
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