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A mechanism for energy transfer from the solar wind to the Martian ionosphere through open magnetic flux rope is proposed based on the observations by Mars Atmosphere and Volatile EvolutioN (MAVEN). The satellite was located in the dayside magnetosheath at an altitude of about 700 km above the northern hemisphere. Collisions between the hot solar wind protons and the cold heavy ions/neutrals in the subsolar region can cool the protons and heat the heavy ions. As a result, the magnetosheath protons are siphoned into the ionosphere due to the thermal pressure gradient of protons and the heated heavy ions escape along the open magnetic field lines. Although direct collisions in the lower-altitude region were not detected, this physical process is demonstrated by MAVEN measurements of enhanced proton density, decreased proton temperature and oppositely directed motions of hot and cool protons within the flux rope, which are very different from the observational features of the flux transfer events near the Earth's magnetopause. This mechanism could universally exist in many contexts where a collisionless plasma region is connected to a collisional plasma region. By reconstructing the magnetic geometry and the cross-section of the flux rope using the Grad-Shafranov technique, the ion loss rates are quantitatively estimated to be on the order of 1023 s-1, which is much higher than previously estimated. [ABSTRACT FROM AUTHOR]

Magnetic reconnection is prevalent in the solar wind and is usually associated with interplanetary coronal mass ejections. We examined a Petschek-like reconnection exhaust (RE) in the front boundary of a magnetic cloud observed by the WIND spacecraft on 1998 June 2 and presented the first observation of a slow shock pair bounding the Petschek-like outflow jet in the interplanetary space. The whole structure contained an Alfvénic accelerated outflow and a pair of reverse slow shocks. The Alfvénic accelerated outflow was identified by Walén analysis. Rankine–Hugoniot relations were applied to confirm the slow shocks bounding the RE. Both shocks strictly satisfied the characteristics of slow shocks: (1) the intermediate Alfvén Mach numbers were both below unit in the up/downstream region; (2) the slow Mach number was above unit in the upstream side but below unit in the downstream side. Plasma was compressed and heated across the trailing slow shock, especially in the shock jump layer that has a temperature 2.4 times that of the upstream. [ABSTRACT FROM AUTHOR]

XWAS is a new software suite for the analysis of the X chromosome in association studies and similar genetic studies. The X chromosome plays an important role in human disease and traits of many species, especially those with sexually dimorphic characteristics. Special attention needs to be given to its analysis due to the unique inheritance pattern, which leads to analytical complications that have resulted in the majority of genome-wide association studies (GWAS) either not considering X or mishandling it with toolsets that had been designed for non-sex chromosomes. We hence developed XWAS to fill the need for tools that are specially designed for analysis of X. Following extensive, stringent, and X-specific quality control, XWAS offers an array of statistical tests of association, including: 1) the standard test between a SNP (single nucleotide polymorphism) and disease risk, including after first stratifying individuals by sex, 2) a test for a differential effect of a SNP on disease between males and females, 3) motivated by X-inactivation, a test for higher variance of a trait in heterozygous females as compared with homozygous females, and 4) for all tests, a version that allows for combining evidence from all SNPs across a gene. We applied the toolset analysis pipeline to 16 GWAS datasets of immune-related disorders and 7 risk factors of coronary artery disease, and discovered several new X-linked genetic associations. XWAS will provide the tools and incentive for others to incorporate the X chromosome into GWAS and similar studies in any species with an XX/XY system, hence enabling discoveries of novel loci implicated in many diseases and in their sexual dimorphism. [ABSTRACT FROM AUTHOR]