The Origin, Early Evolution and Predictability of Solar Eruptions

Coronal mass ejections (CMEs) were discovered in the early 1970s when space-borne coronagraphs revealed that eruptions of plasma are ejected from the Sun. Today, it is known that the Sun produces eruptive flares, filament eruptions, coronal mass ejections and failed eruptions; all thought to be due to a release of energy stored in the coronal magnetic field during its drastic reconfiguration. This review discusses the observations and physical mechanisms behind this eruptive activity, with a view to making an assessment of the current capability of forecasting these events for space weather risk and impact mitigation. Whilst a wealth of observations exist, and detailed models have been developed, there still exists a need to draw these approaches together. In particular more realistic models are encouraged in order to asses the full range of complexity of the solar atmosphere and the criteria for which an eruption is formed. From the observational side, a more detailed understanding of the role of photospheric flows and reconnection is needed in order to identify the evolutionary path that ultimately means a magnetic structure will erupt

Genomic and phenotypic insights from an atlas of genetic effects on DNA methylation

DNA methylation quantitative trait locus (mQTL) analyses on 32,851 participants identify genetic variants associated with DNA methylation at 420,509 sites in blood, resulting in a database of >270,000 independent mQTLs.Characterizing genetic influences on DNA methylation (DNAm) provides an opportunity to understand mechanisms underpinning gene regulation and disease. In the present study, we describe results of DNAm quantitative trait locus (mQTL) analyses on 32,851 participants, identifying genetic variants associated with DNAm at 420,509 DNAm sites in blood. We present a database of >270,000 independent mQTLs, of which 8.5% comprise long-range (trans) associations. Identified mQTL associations explain 15-17% of the additive genetic variance of DNAm. We show that the genetic architecture of DNAm levels is highly polygenic. Using shared genetic control between distal DNAm sites, we constructed networks, identifying 405 discrete genomic communities enriched for genomic annotations and complex traits. Shared genetic variants are associated with both DNAm levels and complex diseases, but only in a minority of cases do these associations reflect causal relationships from DNAm to trait or vice versa, indicating a more complex genotype-phenotype map than previously anticipated.Molecular Epidemiolog

Comparative Molecular Analysis of Gastrointestinal Adenocarcinomas

We analyzed 921 adenocarcinomas of the esophagus, stomach, colon, and rectum to examine shared and distinguishing molecular characteristics of gastrointestinal tract adenocarcinomas (GIACs). Hypermutated tumors were distinct regardless of cancer type and comprised those enriched for insertions/deletions, representing microsatellite instability cases with epigenetic silencing of MLH1 in the context of CpG island methylator phenotype, plus tumors with elevated single-nucleotide variants associated with mutations in POLE. Tumors with chromosomal instability were diverse, with gastroesophageal adenocarcinomas harboring fragmented genomes associated with genomic doubling and distinct mutational signatures. We identified a group of tumors in the colon and rectum lacking hypermutation and aneuploidy termed genome stable and enriched in DNA hypermethylation and mutations in KRAS, SOX9, and PCBP1. Liu et al. analyze 921 gastrointestinal (GI) tract adenocarcinomas and find that hypermutated tumors are enriched for insertions/deletions, upper GI tumors with chromosomal instability harbor fragmented genomes, and a group of genome-stable colorectal tumors are enriched in mutations in SOX9 and PCBP1

MONTE CARLO SIMULATION OF ICE Ih : COMPARISON OF BULK MELTING AT CONSTANT PRESSURE AND STRUCTURE OF ICE LAYERS ON AN ICE NUCLEATING SUBSTRATE

Recently effective pair potentials (1) and Metropolis Monte Carlo methods have been used to study the melting of a periodic rigid molecule model ice system at constant volume (2, 3) near 290 K. We have extended these studies to examination of the system at constant pressure and present the results for approximately 1 atm pressure. In this approach the constant number, pressure and temperature (NPT) ensemble is approximated by treating the volume as an additional variable in the Metropolis Monte Carlo procedure (4-7). The unit cell for these calculations contains 192 rigid central force (1) water molecules and the initial configurations are taken from the constant number, volume and temperature (NVT) equilibrated system (3) at 260 K. This initial ice Ih unit cell has approximately zero dipole and quadrupole moments and was shown to remain in the ice Ih structure over a range of temperature from 20 K to about 290 K in constant NVT ensemble studies. The pressure is found to be extremely sensitive to the intermolecular interactions and to the instantaneous density of molecules in the unit cell. The unit cell properties (dipole moment, ice structure factors, specific heat, and pair correlation functions) will be presented. A comparison will be made with simulations of two water layers on a model ice nucleating substrate (8) at 200 K and 265 K near zero pressure. At 200 K the structure of the top layer of this system shows considerable disorder and liquid - like properties, while the water layer adjacent to the substrate has a solid ice - like hexagonal ring structure. There appears to be no preference for water dipole orientation in the exposed layer of water molecules. The liquid-like properties of the exposed layers in this system at 200 K and the melting of the bulk near 290 K are consistent with recent observations that surface layers have noticably reduced solid-liquid transition temperatures (9). When these absorbed water layers are subjected to a large external electric field or constant presure (~ 200 atm) there appears to no significant change in the exposed layer structure and liquid-like states. Unit cell properties for the layer systems will be discussed. The motivation for these studies has been to examine the effect of pressure, temperature and other external perturbations (such as substrate structure and substrate defects) on atmospheric ice nucleation