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

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

Obstetric outcome study of oligohydramnios beyond 34 completed weeks of gestation

Background: Perinatal morbidity and mortality are significantly increased when oligohydramnios is present. As the amniotic fluid volume decreases, the perinatal mortality rate increases. The incidence of major congenital anomalies with IUGR also increases as the amniotic fluid volume declines. There is a close association between declining placental function in the latter part of the third trimester and amniotic fluid volume1. Thus, post term patients are at a greater risk for development of oligohydramnios. Fetal anomalies that results in oligohydramnios classically involve the urinary tract. The most frequently mentioned renal anomalies include bilateral renal agenesis, multicystic dysplastic kidneys, bladder outlet obstruction and infantile polycystic kidneys.Methods: All antenatal patients seen in the Department of Obstetrics and Gynecology at Sri Siddhartha Medical College and Research Centre between January 2015 to January 2017, who were willing to participate in the trial study were enrolled. Ultrasound GE Voulson S8-PRO equipped with 3.5 MHz transducer was used to measure the amniotic fluid index. The AFI in each group was noted and the pregnancy outcome in each group was determined. At the time of delivery following data variables were collected and compiled.Results: There were 105 women, who were divided into three groups of 35 each. Those women with AFI<5 had more chances of emergency caesarian section, the causes were fetal distress with variable and late fetal heart decelerations. The incidence of meconium stained liquor and NICU admission were more.Conclusions: The women with AFI<5 had more chances of emergency caesarian section, the causes were fetal distress with variable and late fetal heart decelerations. Amniotic Fluid Index is a valuable screening test for detecting fetuses that may have poor perinatal outcome

Evaluation of role of laparoscopy in determining etiology of infertility

Background: Although population explosion is a major problem in India, infertility appears to be a problem in 5-15% of Indian population. All these patients require evaluation. Laparoscopy plays a valuable role in the diagnosis of infertility. After thorough clinical examination and specific investigations, diagnostic laparoscopy is performed to detect patency of tubes, morphological defects in uterus, ovaries and tuboperitoineal factors. This study was conducted to assess the role of diagnostic laparoscopy in the investigation of female infertility and to evaluate the various causes of infertility like endometriosis, PCOD tubal and peritoneal factors, uterine anomalies, tuberculosis etc. by using diagnostic laparoscopy.Methods: Study was carried out in 60 infertile patients attending outpatient department of hospitals attached to Sri Siddhartha Medical College Hospital, Tumkur.  Both primary and secondary infertility patients who were anxious to conceive and undergo diagnostic laparoscopy were evaluated. Those who were not willing and who were contraindicated for the procedure were excluded.Results: Diagnostic laparoscopy was performed in 72% of primary and 28% of secondary infertility patients. Majority of the patients of primary infertility were in age group 21-25 years and that of secondary were between 26-30 years. Majority of patients in both the groups had duration of 1-5 year of infertility. In our study tubal factors (50%) contributed to majority of the infertility causes. Complication rate was minimum and was comparable to other standard studies.Conclusions: Laparoscopic is the gold standard for diagnosing tubal and peritoneal disease, endometriosis and other pelvic pathology, because no other imaging technique gives the same degree of sensitivity or specificity. Hence diagnostic laparoscopy is an indispensable tool in the evaluation in the evaluation infertility

Smart Meter Privacy: A Utility-Privacy Framework

End-user privacy in smart meter measurements is a well-known challenge in the smart grid. The solutions offered thus far have been tied to specific technologies such as batteries or assumptions on data usage. Existing solutions have also not quantified the loss of benefit (utility) that results from any such privacy-preserving approach. Using tools from information theory, a new framework is presented that abstracts both the privacy and the utility requirements of smart meter data. This leads to a novel privacy-utility tradeoff problem with minimal assumptions that is tractable. Specifically for a stationary Gaussian Markov model of the electricity load, it is shown that the optimal utility-and-privacy preserving solution requires filtering out frequency components that are low in power, and this approach appears to encompass most of the proposed privacy approaches.Comment: Accepted for publication and presentation at the IEEE SmartGridComm. 201

IMAGE FUSION ALGORITHM FOR FUSION OF PANCHROMATIC AND MULTISPECTRAL IMAGES FOR HIGH SPATIAL INFORMATION WHILE PRESERVING SPECTRAL INFORMATION CONTENT

In this paper image fusion algorithm for enhancing spatial quality of the multispectral image while maintaining the spectral quality of the multispectral image is proposed. The fusion algorithm is developed based on high frequency components injection to the multispectral image to improve the spatial quality of the fused image. High frequency component is generated using the Laplacian filter. Construct the saliency map and initial weight map. Finally optimum weight parameter is calculated for each band using the guided filter, using this optimum weight parameter panchromatic and multispectral images are fused to enhance the spatial quality of the multispectral image

Human Resource Management Practices and Organizational Performance in Public Sector Organizations: with reference to Development Officers in the Colombo District in Sri Lanka

Human resources management concerns how people are employed, utilized, and maintained effectively and efficiently in achieving organizational objectives.&nbsp; &nbsp;The performance of any organization largely depends on its human resources. Among the human resources management practices, recruitment, and selection of the right pool of employees, proper training and development, performance appraisal, and compensation directly affect achieving organizational objectives. However, these Human Resource (HR) practices in the public sector, especially in relation to the position of Development Officers (DOs) of Sri Lanka have not been practiced in an effective manner. Recruitment of Graduates as Development Officers has been a major reason for increasing the growth of public service in the country. Since the 1990s, the government of Sri Lanka has practiced bulk recruitment of graduates without having a clear and formal duty list, service minutes, recruitment procedures, training and development programs, promotion policy, and salary scale. The main purpose of this study is to discuss the existing Human Resource Management (HRM) practices, identify strengths and weaknesses of the existing HRM practices, and examine how these weaknesses affect the performance of the public sector organizations in relation to Development Officers in the public sector in Sri Lanka. The study used a qualitative research method with the inductive approach. Data were collected through in-depth interviews from all 13 Divisional Secretaries in the Colombo District and the data were analyzed narratively. The study revealed that the existing recruiting, training, and performance appraisal practices negatively affect the performance of the public sector due to some weaknesses in these practices.&nbsp; Finally, this study proposes policy recommendations for improving the effectiveness of these practices for enhancing the public sector performance in Sri Lanka. Keywords: Human resource management practices, Development officers, Public sector, Sri Lank

Enhancing Employability of Management Graduates of State Universities in Sri Lanka: An Examination of Job Market Requirements

Higher education helps in enhancing the human resources required for development. Universities and higher education institutes play a vital role in disseminating and creating knowledge through teaching and research, contributing to the development of any country. The quality and relevance of the output (graduates) of higher education institutes need to be enhanced to increase graduates’ employability. Graduate unemployment has become a significant problem in Sri Lanka. If graduates are unemployed, this will directly and negatively influence economic development. The main objectives of this study are to identify job market requirements of the industry and factors affecting the success of the graduates’ interviews. This study used qualitative research methods as a mono method. &nbsp;Data were collected using advertisements from two selected leading English and Sinhala weekend newspapers published from October 2019 to January 2020, and in-depth interviews were conducted with selected Human Resource managers. Newspaper analysis and job market requirement analysis were done using an inductive thematic analysis approach. Five core skills were identified as the job market requirements, namely, problem-solving skills, communication skills, numeracy skills, computer skills, and interpersonal skills. Leadership qualities, communication and presentation ability, teamwork, interpersonal relations, practical knowledge, positive attitudes, hardworking characteristics, well-preparedness at the interview, and a clear understanding of the graduate's career path mainly affect the graduate interview's success. The study proposes policy measures to improve the employability of management graduates of state universities in Sri Lanka. &nbsp;Keywords: Employability, Management Graduates, State Universities, job market requirements, Sri Lank

Electronic structure and optical properties of ZnX (X=O, S, Se, Te)

Electronic band structure and optical properties of zinc monochalcogenides with zinc-blende- and wurtzite-type structures were studied using the ab initio density functional method within the LDA, GGA, and LDA+U approaches. Calculations of the optical spectra have been performed for the energy range 0-20 eV, with and without including spin-orbit coupling. Reflectivity, absorption and extinction coefficients, and refractive index have been computed from the imaginary part of the dielectric function using the Kramers--Kronig transformations. A rigid shift of the calculated optical spectra is found to provide a good first approximation to reproduce experimental observations for almost all the zinc monochalcogenide phases considered. By inspection of the calculated and experimentally determined band-gap values for the zinc monochalcogenide series, the band gap of ZnO with zinc-blende structure has been estimated.Comment: 17 pages, 10 figure