Solar Physics with the Square Kilometre Array

The Square Kilometre Array (SKA) will be the largest radio telescope ever built, aiming to provide collecting area larger than 1 km$^2$. The SKA will have two independent instruments, SKA-LOW comprising of dipoles organized as aperture arrays in Australia and SKA-MID comprising of dishes in South Africa. Currently the phase-1 of SKA, referred to as SKA1, is in its late design stage and construction is expected to start in 2020. Both SKA1-LOW (frequency range of 50-350 MHz) and SKA1-MID Bands 1, 2, and 5 (frequency ranges of 350-1050, 950-1760, and 4600-15300 MHz, respectively) are important for solar observations. In this paper we present SKA's unique capabilities in terms of spatial, spectral, and temporal resolution, as well as sensitivity and show that they have the potential to provide major new insights in solar physics topics of capital importance including (i) the structure and evolution of the solar corona, (ii) coronal heating, (iii) solar flare dynamics including particle acceleration and transport, (iv) the dynamics and structure of coronal mass ejections, and (v) the solar aspects of space weather. Observations of the Sun jointly with the new generation of ground-based and space-borne instruments promise unprecedented discoveries.Comment: Accepted for publication in Advances in Space Researc

Effect of Nitrogen and Phosphorus Application on Productivity, Nutrient Uptake and Quality of Teosinte (\u3cem\u3eZea mexicana\u3c/em\u3e L.) Fodder

Teosinte (Zea mexicana L.) is popularly known as Makchari being a close relative of maize. It provides succulent, palatable and nutritive fodder during Kharif season for feeding the animals as green fodder or conserved fodder in the form of silage. Teosinte is an excellent multicut fodder which gives high yield of nutritious green lush fodder in 65-70 days with less inputs as compared to maize. Nitrogen is an essential component of proteins, nucleic acid, enzymes, coenzymes, chlorophyll and cell wall. Phosphorus plays a vital role in crop production as it is involved in CO2 fixation, sugar metabolism, energy storage and transfer. Nutrient deficiency along with imbalanced and non-judicious fertilizers use of the important limiting factor that may affect the yield and quality of teosinte forage. In India about 62% and 49% soils are deficient in nitrogen and phosphorus (Gibson, 2006). The application of nitrogen and phosphorus is considered to be the most important which improves the yield and quality of fodder. The present investigation was under taken to assess the effect of N and P application on productivity, nutrient uptake and quality of teosinte fodder

Study of prevalence of bacterial vaginosis in preterm and term labour patients

Background: Bacterial vaginosis (BV) is a clinical condition caused by replacement of the normal hydrogen peroxide producing Lactobacillus species with high concentrations of aerobic and anaerobic bacteria. Studies have shown that spontaneous abortion, preterm labour (PTL), premature birth, preterm premature rupture of membranes, amniotic fluid infection, and postpartum endometritis are increased because of infection with BV. In India, not many studies have been done to estimate the prevalence and association of BV with preterm labour, hence this study is being taken up to know the prevalence of BV in preterm and term labour patients and its relationship with preterm delivery, low birth weight of baby and puerperal sepsis.The objective of the present study was to observe the prevalence of bacterial vaginosis in women presenting with preterm and term labour, its impact on preterm and term delivery and to analyze the maternal and fetal complications associated with BV.Methods: An observational study involving 100 patients with preterm and term labour (50 patients in each group) was conducted at a BNMCCC, Government Medical College, Amritsar. Women fulfilling the Amsel’s criteria and/or a score of 7 or more on gram staining of vaginal smears (Nugent’s score) was considered to have bacterial vaginosis.Results: The proportion of patients, who fulfilled Amsel’s criteria and/or a Nugent’s score of 7 or more for the diagnosis of BV, was more in PTL group versus term labour group, and the difference was statistically significant. Prevalence of BV in preterm labour and term labour patients was 18(36%) versus 4(8%) respectively. In PTL group, 27.8% of low birth weight neonates were born to BV positive mothers versus 3.1% were born to BV negative mothers. Maternal postpartum complications observed were 33.3% with BV versus 6.25% without BV in PTL group.Conclusions: BV is major risk factor for PTL. Therefore, the testing and prompt treatment of BV may reduce the risk of PTL. This will also go a long way in the prevention of maternal morbidity and neonatal complications due to prematurity

Solar and Heliospheric Physics with the Square Kilometre Array

The fields of solar radiophysics and solar system radio physics, or radio heliophysics, will benefit immensely from an instrument with the capabilities projected for SKA. Potential applications include interplanetary scintillation (IPS), radio-burst tracking, and solar spectral radio imaging with a superior sensitivity. These will provide breakthrough new insights and results in topics of fundamental importance, such as the physics of impulsive energy releases, magnetohydrodynamic oscillations and turbulence, the dynamics of post-eruptive processes, energetic particle acceleration, the structure of the solar wind and the development and evolution of solar wind transients at distances up to and beyond the orbit of the Earth. The combination of the high spectral, time and spatial resolution and the unprecedented sensitivity of the SKA will radically advance our understanding of basic physical processes operating in solar and heliospheric plasmas and provide a solid foundation for the forecasting of space weather events.Comment: 15 pages, Proceedings of Advancing Astrophysics with the Square Kilometre Array (AASKA14). 9 -13 June, 2014. Giardini Naxos, Italy. Online at http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=215, id.16

First detections of 610 MHz radio emission from hot magnetic stars

We have carried out a study of radio emission from a small sample of magnetic O- and B-type stars using the Giant Metrewave Radio Telescope, with the goal of investigating their magnetospheres at low frequencies. These are the lowest frequency radio measurements ever obtained of hot magnetic stars. The observations were taken at random rotational phases in the 1390 and the 610 MHz bands. Out of the 8 stars, we detect five B-type stars in both the 1390 and the 610 MHz bands. The O-type stars were observed only in the 1390 MHz band, and no detections were obtained. We explain this result as a consequence of free-free absorption by the free-flowing stellar wind exterior to the closed magnetosphere. We also study the variability of individual stars. One star - HD 133880 - exhibits remarkably strong and rapid variability of its low frequency flux density. We discuss the possibility of this emission being coherent emission as reported for CU Vir by Trigilio et al. (2000).Comment: 9 pages, 4 figures, 4 tables, submitted to MNRA

Ubiquitin-dependent regulation of MEKK2/3-MEK5-ERK5 signaling module by XIAP and cIAP1

Mitogen-activated protein kinases (MAPKs) are highly conserved protein kinase modules, and they control fundamental cellular processes. While the activation of MAPKs has been well studied, little is known on the mechanisms driving their inactivation. Here we uncover a role for ubiquitination in the inactivation of a MAPK module. Extracellular-signal-regulated kinase 5 (ERK5) is a unique, conserved member of the MAPK family and is activated in response to various stimuli through a three-tier cascade constituting MEK5 and MEKK2/3. We reveal an unexpected role for Inhibitors of Apoptosis Proteins (IAPs) in the inactivation of ERK5 pathway in a bimodal manner involving direct interaction and ubiquitination. XIAP directly interacts with MEKK2/3 and competes with PB1 domain-mediated binding to MEK5. XIAP and cIAP1 conjugate predominantly K63-linked ubiquitin chains to MEKK2 and MEKK3 which directly impede MEK5-ERK5 interaction in a trimeric complex leading to ERK5 inactivation. Consistently, loss of XIAP or cIAP1 by various strategies leads to hyperactivation of ERK5 in normal and tumorigenic cells. Loss of XIAP promotes differentiation of human primary skeletal myoblasts to myocytes in a MEKK2/3-ERK5-dependent manner. Our results reveal a novel, obligatory role for IAPs and ubiquitination in the physical and functional disassembly of ERK5-MAPK module and human muscle cell differentiation

Limb Girdle Muscular Dystrophy due to Digenic Inheritance of DES and CAPN3 Mutations

We report the clinical and genetic analysis of a 63-year-old man with progressive weakness developing over more than 20 years. Prior to his initial visit, he underwent multiple neurological and rheumatological evaluations and was treated for possible inflammatory myopathy. He did not respond to any treatment that was prescribed and was referred to our center for another opinion. He underwent a neurological evaluation, electromyography, magnetic resonance imaging of his legs, and a muscle biopsy. All testing indicated a chronic myopathy without inflammatory features suggesting a genetic myopathy. Whole-exome sequencing testing more than 50 genes known to cause myopathy revealed variants in the COL6A3 (rs144651558), RYR1 (rs143445685), CAPN3 (rs138172448), and DES (rs144901249) genes. We hypothesized that the inheritance pattern could follow a digenic pattern of inheritance. Screening for these polymorphisms in an unaffected sister revealed the presence of all these same variants except for that in the CAPN3 gene. All variants were studied to determine their frequency and if they had been previously reported as mutations. They were also subjected to protein modeling programs, including SIFT, PolyPhen, and MutationTaster. This analysis indicated that the CAPN3 variant c.1663G>A (rs138172448), which results in a p.Val555Ile change, and the DES gene variant c.656C>T (rs144901249), which results in a p.Thr219Ile change, are both predicted to be damaging. These 2 variants were further investigated employing the STRING program that analyzes protein networks and pathways. This analysis provided further support for our hypothesis that these mutations in the CAPN3 and DES genes, through digenic inheritance, are the cause of the myopathy in this patient