Guided flows in coronal magnetic flux tubes

There is evidence for coronal plasma flows to break down into fragments and to be laminar. We investigate this effect by modeling flows confined along magnetic channels. We consider a full MHD model of a solar atmosphere box with a dipole magnetic field. We compare the propagation of a cylindrical flow perfectly aligned to the field to that of another one with a slight misalignment. We assume a flow speed of 200 km/s, and an ambient magnetic field of 30 G. We find that while the aligned flow maintains its cylindrical symmetry while it travels along the magnetic tube, the misaligned one is rapidly squashed on one side, becoming laminar and eventually fragmented because of the interaction and backreaction of the magnetic field. This model could explain an observation of erupted fragments that fall back as thin and elongated strands and end up onto the solar surface in a hedge-like configuration, made by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. The initial alignment of plasma flow plays an important role in determining the possible laminar structure and fragmentation of flows while they travel along magnetic channels.Comment: 11 pages, 8 figures, accepted for publication, movies available upon request to the first autho

Data_Sheet_1_Mitotic-Spindle Organizing Protein MztA Mediates Septation Signaling by Suppressing the Regulatory Subunit of Protein Phosphatase 2A-ParA in Aspergillus nidulans.PDF

<p>The proper timing and positioning of cytokinesis/septation is crucial for hyphal growth and conidiation in Aspergillus nidulans. The septation initiation network (SIN) components are a conserved spindle pole body (SPB) localized signaling cascade and the terminal kinase complex SidB-MobA, which must localize on the SPB in this pathway to trigger septation/cytokinesis. The regulatory subunit of phosphatase PP2A-ParA has been identified to be a negative regulator capable of inactivating the SIN. However, little is known about how ParA regulates the SIN pathway and whether ParA regulates the septum formation process through affecting the SPB-localized SIN proteins. In this study, through RNA-Seq and genetic approaches, we identified a new positive septation regulator, a putative mitotic-spindle organizing protein and a yeast Mzt1 homolog MztA, which acts antagonistically toward PP2A-ParA to coordinately regulate the SPB-localized SIN proteins SidB-MobA during septation. These findings imply that regulators, phosphatase PP2A-ParA and MztA counteract the septation function probably through balancing the polymerization and depolymerization of microtubules at the SPB.</p

Mass Spectrometry Identification of <i>N</i>‑Chlorinated Dipeptides in Drinking Water

We report the identification of <i>N</i>-chlorinated dipeptides as chlorination products in drinking water using complementary high-resolution quadrupole time-of-flight (QTOF) and quadrupole ion-trap mass spectrometry techniques. First, three model dipeptides, tyrosylglycine (Tyr-Gly), tyrosylalanine (Tyr-Ala), and phenylalanylglycine (Phe-Gly), reacted with sodium hypochlorite, and these reaction solutions were analyzed by QTOF. <i>N</i>-Cl-Tyr-Gly, <i>N</i>,<i>N</i>-di-Cl-Tyr-Gly, <i>N</i>-Cl-Phe-Gly, <i>N</i>,<i>N</i>-di-Cl-Phe-Gly, <i>N</i>-Cl-Tyr-Ala, and <i>N</i>,<i>N</i>-di-Cl-Tyr-Ala were identified as the major products based on accurate masses, ³⁵Cl/³⁷Cl isotopic patterns, and MS/MS spectra. These identified <i>N</i>-chlorinated dipeptides were synthesized and found to be stable in water over 10 days except <i>N</i>,<i>N</i>-di-Cl-Phe-Gly. To enable sensitive detection of <i>N</i>-chlorinated dipeptides in authentic water, we developed a high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method with multiple reaction monitoring (MRM) mode. <i>N</i>-Cl-Tyr-Gly, <i>N</i>,<i>N</i>-di-Cl-Tyr-Gly, <i>N</i>-Cl-Phe-Gly, <i>N</i>-Cl-Tyr-Ala, and <i>N</i>,<i>N</i>-di-Cl-Tyr-Ala along with their corresponding dipeptides were detected in authentic tap water samples. The dipeptides were clearly detected in the raw water, but the <i>N</i>-chlorinated dipeptides were at background levels. These results suggest that the <i>N</i>-chlorinated dipeptides are produced by chlorination. This study has identified <i>N</i>-chlorinated dipeptides as new disinfection byproducts in drinking water. The strategy developed in this study can be used to identify chlorination products of other peptides in drinking water

DataSheet1_Linking land use with riverine water quality: A multi-spatial scale analysis relating to various riparian strips.PDF

Exploring linkages between riverine water quality and land use is of great importance for catchment management and water quality conservation. Relationships between them are complex and site-specific. Therefore, land-use/landscape effects on water quality remain to be investigated. Multivariate statistics and empirical models are used to examine the influences of seasonality (wet and dry seasons), land use in various riparian strips, on water quality seasonality in the river networks of the Three Gorges Reservoir Area. Redundancy analysis (RDA) shows a comparable effect of land use on overall water quality (OWQ) during the two seasons. The variance of OWQ explained is generally higher in the 50 m riparian zone, whilst, the variance is higher along 200 m riparian in the wet season with land use composition presented as actual area. The explanatory variables of land use indices for the OWQ are quite distinct. Multiple linear regression (MLR) modeling indicates that models of water quality parameters (WQPs) depend on seasonality, riparian zone and representation of land use indices (calculated from percentage and actual area), this results in predictor variables of WQPs are highly variable. Land use within the 50 m riparian zone can predict WQPs well, and land use along the riparian zones predicts WQPs better in the dry season. We firstly compared the impacts of multi-riparian land use indices (presented as percentage and actual area) in combination with land use configuration on water quality. Our study provides critical information for efficiently land-use planning to protect water quality.</p

CoP and CoM AP displacement ranges.

<p>CoP and CoM AP displacement ranges.</p

Coordinate values for objective posture.

<p>Coordinate values for objective posture.</p

Human stance postural control.

<p>Red block: neural controller to actuate muscles during quiet standing. Green block: musculoskeletal model. Flesh-colored blocks: 120-ms neurological time delay. The delay is comprised of a 40-ms feedback delay, 40-ms transmission delay, and (at most) 40-ms activation dynamics delay. The activation dynamics delay corresponds to a 20-ms activation time delay during the muscle activation process and a 40-ms deactivation time delay during the muscle deactivation process.</p

Simulated muscle activations.

<p>The red dots are simulated activations, the black dots are mode values, and the gray shaded boxes indicate the experimental activation data ranges. The experimental mode values and activation data ranges were reported in [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163212#pone.0163212.ref071" target="_blank">71</a>].</p

Variable design results.

<p>Variable design results.</p

Musculoskeletal model.

<p>(a) Musculoskeletal model. HAT: head, arms, and torso. The OpenSim musculoskeletal model consists of seven DoFs and 70 muscular-tendon actuators. <i>q</i>₁–<i>q</i>₇ are the seven joint coordinates, each of which has one DoF for joint flexion and extension. (<i>q</i>₁–<i>q</i>₇: Lumbar, right hip, right knee, right ankle, left hip, left knee, and left ankle flexion-extension, respectively.) (b) CoM position and projection at base of support (BoS). The green-and-black ball is the CoM position, and the green ball is the vertical CoM projection at the BoS. (c) Foot-ground contact. The foot-ground contact is represented by four compliant spheres (heel, toe, and two metatarsals) on each foot, with Coulomb friction.</p