X-ray activity cycle on the active ultra-fast rotator AB Dor A? Implication of correlated coronal and photometric variability

Although chromospheric activity cycles have been studied in a larger number of late-type stars for quite some time, very little is known about coronal activity-cycles in other stars and their similarities or dissimilarities with the solar activity cycle. While it is usually assumed that cyclic activity is present only in stars of low to moderate activity, we investigate whether the ultra-fast rotator AB Dor, a K dwarf exhibiting signs of substantial magnetic activity in essentially all wavelength bands, exhibits a X-ray activity cycle in analogy to its photospheric activity cycle of about 17 years and possible correlations between these bands. We analysed the combined optical photometric data of AB Dor A, which span ~35 years. Additionally, we used ROSAT and XMM-Newton X-ray observations of AB Dor A to study the long-term evolution of magnetic activity in this active K dwarf over nearly three decades and searched for X-ray activity cycles and related photometric brightness changes. AB Dor A exhibits photometric brightness variations ranging between 6.75 < Vmag < 7.15 while the X-ray luminosities range between 29.8 < log LX [erg/s] < 30.2 in the 0.3-2.5 keV. As a very active star, AB Dor A shows frequent X-ray flaring, but, in the long XMM-Newton observations a kind of basal state is attained very often. This basal state probably varies with the photospheric activity-cycle of AB Dor A which has a period of ~17 years, but, the X-ray variability amounts at most to a factor of ~2, which is, much lower than the typical cycle amplitudes found on the Sun.Comment: 10 page

Structure and variability in the corona of the ultrafast rotator LO Peg

Low-mass ultrafast rotators show the typical signatures of magnetic activity and are known to produce flares, probably as a result of magnetic reconnection. As a consequence, the coronae of these stars exhibit very large X-ray luminosities and high plasma temperatures, as well as a pronounced inverse FIP effect. To probe the relationship between the coronal properties with a spectral type of ultra-fast rotators with rotation period P < 1d, we analyse the K3 rapid-rotator LO Peg observed with XMM-Newton and compare it with other low-mass rapid rotators of spectral types G9-M1. We investigate the temporal evolution of coronal properties like the temperatures, emission measures, abundances, densities and the morphology of the involved coronal structures. We find two distinguishable levels of activity in the XMM-Newton observation of LO~Peg, which shows significant X-ray variability both in phase and amplitude, implying the presence of an evolving active region on the surface. The X-ray flux varies by 28%, possibly due to rotational modulation. During our observation, a large X-ray flare with a peak X-ray luminosity of 2E30 erg/s and an energy of 7.3E33 erg was observed. At the flare onset we obtain clear signatures for the occurrence of the Neupert effect. The flare plasma also shows an enhancement of iron by a factor of 2 during the rise and peak phase of the flare. Our modeling analysis suggests that the scale size of the flaring X-ray plasma is smaller than 0.5 R_star. Further, the flare loop length appears to be smaller than the pressure scale height of the flaring plasma. Our studies show that the X-ray properties of the LO~Peg are very similar to those of other low-mass ultrafast rotators, i.e., the X-ray luminosity is very close to saturation, its coronal abundances follow a trend of increasing abundance with increasing first ionisation potential, the so-called inverse FIP effect.Comment: 11 pages, 15 figures and 4 tables. Accepted for publication by Astronomy and Astrophysic

Strong interrelationship between anomalous electric-field induced lattice strain along non-polar direction and domain reorientation in pseudorhombohedral piezoelectric ceramic BiScO3-PbTiO3

The lattice strain and domain switching behaviour was investigated as a function of cyclic field and grain orientation for a pseudorhombohedral composition of the high Curie point piezoelectric system xBiScO3 - (1-x)PbTiO3 (x = 0.40) by in-situ electric field diffraction technique with high energy synchrotron x-rays. Along the field direction, the system exhibts five time large strain along 100 as compared to the 111 direction. A one-to-one correspondence between the 200 lattice strain and the 111 domain switching suggests a strong correlation between the two phenomena.Comment: 11 pages, 7 figure

Catalytic Philanthropy In India

Catalytic Philanthropy is still in its infancy in India. Despite this, there are a surprising number of exemplary cases where Indian philanthropists are creating large-scale social change far beyond the resources invested. This report highlights these practices as well as the key issues that need to be addressed to accelerate its evolution

A STUDY ON INSTRUCTIONAL SUPERVISION BY PRINCIPALS IN TYPE 1C AND TYPE 2 SCHOOLS IN SRI LANKA

The main purpose of this study was to examine how principals’ engage in instructional supervision in Type 1C and Type 2 school in Sri Lanka. Three research questions were used to guide the study to a rational conclusion. Mixed Method was adopted in the study in order to triangulate data. Both questionnaire and semi structured interview schedules &nbsp;were used to obtain relevant data from 150 teachers, 10 principals and 10 sectional heads in 10 selected Type 1C and Type 2 &nbsp;schools using the simple random sampling techniques. Tables, percentages and graphs were used to analyze quantitative data and the qualitative data was analyzed by using thematic analysis and answer the research questions. The findings revealed that all the principals in the type 1C and Type 2 schools have positive perception about the role of instructional supervision and have formed an instructional supervisory team including the principal. However, the study revealed that the majority of principals in the type 1C and Type 2 schools do not engage in role of instructional supervision due to the major challenge of having engage in general administration roles than the instructional roles. The study further revealed that the existing internal supervisory team engage in instructional supervision role rarely and do not conduct post observational discussions which facilitate teachers to identify their strength and the areas that need further improvement. It is, therefore, recommended that, the principals need to carry out an adequate instructional supervision of teachers so as to improve their teaching skills and professional development. &nbsp

X-ray emission from the super-Earth host GJ 1214

Stellar activity can produce large amounts of high-energy radiation, which is absorbed by the planetary atmosphere leading to irradiation-driven mass-loss. We present the detection and an investigation of high-energy emission in a transiting super-Earth host system, GJ 1214, based on an XMM-Newton observation. We derive an X-ray luminosity LX=7.4E25 erg/s and a corresponding activity level of log(LX/Lbol)~ -5.3. Further, we determine a coronal temperature of about -3.5 MK, which is typical for coronal emission of moderately active low-mass stars. We estimate that GJ 1214 b evaporates at a rate of 1.3E10 g/s and has lost a total of ~2-5.6 MEarth.Comment: 5 pages, 3 figures, published in APJ

Maximally Recoverable Codes with Hierarchical Locality

Maximally recoverable codes are a class of codes which recover from all potentially recoverable erasure patterns given the locality constraints of the code. In earlier works, these codes have been studied in the context of codes with locality. The notion of locality has been extended to hierarchical locality, which allows for locality to gradually increase in levels with the increase in the number of erasures. We consider the locality constraints imposed by codes with two-level hierarchical locality and define maximally recoverable codes with data-local and local hierarchical locality. We derive certain properties related to their punctured codes and minimum distance. We give a procedure to construct hierarchical data-local MRCs from hierarchical local MRCs. We provide a construction of hierarchical local MRCs for all parameters. For the case of one global parity, we provide a different construction of hierarchical local MRC over a lower field size.Comment: 6 pages, accepted to National Conference of Communications (NCC) 201

Agricultural Marketing and Inclusive Growth in India What does the Survey Data Suggest? The Case of Two Villages in Medak District of Telangana State

This paper is an attempt to study the role of agricultural marketing in impacting the small and large farmers in rural Telangana in terms of their participation in selling activities, obtaining  remunerative prices, and the problems relating transport of their produce and finally the impact on their economic well being. Our empirical analysis based on primary as well as secondary data suggests that in spite of limited knowledge about the usefulness and functioning of regulated agricultural marketing practices the small and marginal farmers of the study area have been benefited due to better prices and other market related facilities. The study uses the logit model to discern the impact of various socio economic  variables on the decision of sample farmers to participate in the regulated market practices which help the small and marginal farmers in improving their economic well being and thus pave the way for them to be included in the growth process. However, there is a need to do a lot to derive more and tangible benefits through regulated markets in rural Telangana. Keywords: Agricultural marketing, inclusive growth, awareness, price differential, logit mode