A Study of Astronomical Polarization, Polarimetric Observations and Polarimetry of Exoplanets

Astronomical polarization has become one useful tool to study a number of astronomical objects and related astrophysical mechanisms. The polarization of electromagnetic waves is caused by various astronomical phenomena. One such phenomenon is when the light emitting from a planet(s) hosting star is reflected by the orbiting planet(s). However, the degree of polarization due to such events is tiny and their observations require highly sensitive polarimeters. DiPol-2 is a one such high sensitivity polarimeter that can measure polarization degree of more than $10^{-5}$. The polarimeter is presently installed with T60 telescope at Haleakal\={a} observatory in Hawaii and is operated remotely by Physics and Astronomy department at University of Turku. We used DiPol-2 to observe a hot Jupiter exoplanet named $\upsilon$ And b in B, V and R passbands. These observations were made using the combination of T60 and DiPol-2. It was the first time that these instruments were used together to record polarimetric observations of an exoplanet. Stokes parameters describe the state of polarization and variations in these parameters can help to deduce orbital parameters and/or stellar, planetary characteristics. This process however requires that data visualization to be compared with numerous models that have been developed to interpret polarimetric observations. The polarimetric observations started in the second half of 2016 and continued till early 2019. We observed the target whenever observing time allocation and observation conditions allowed it. The observational data then went through a lengthy process of data transfer and data reduction. For data analysis, Lomb-Scargle algorithm was used to deduce orbital periods present in the data. Lomb-Scargle periodogram showed a number of peaks with different orbital periods. It was deduced that the presence of multiple orbital periods was due to magnetic activity on the stellar surface that contaminated polarimetric signals of the exoplanet. To further visualize the data, curve fitting was performed using Fourier series in order to deduce orbital peaks of $\upsilon$ And b and estimate the planetary albedo. We were able to estimate values for a few parameters but at this point it has not been possible to separate planetary signal from the stellar signal. This task would require a sophisticated model and that was beyond the scope of this study

High-precision broadband linear polarimetry of early-type binaries IV. Binary system of DH Cephei in the open cluster of NGC 7380

DH~Cephei is a well known massive O+O-type binary system on the northern sky, residing in the young open cluster NGC~7380. Our high-precision multi-band polarimetry has clearly revealed that variations of linear polarizations in this system are synchronous with the phase of the orbital period. We have used the observed variations of Stokes parameters $q$ and $u$ to derive the orbital inclination $i$, orientation $\Omega$, and the direction of rotation. In order to determine the contribution from interstellar polarization, we have carried out new observations of polarization of field stars with precisely measured parallaxes. The variations of Stokes parameters in all three $B$, $V$, and $R$ passbands clearly exhibit an unambiguous periodic signal at 1.055 d with the amplitude of variations $\sim$$0.2\%$ which corresponds to half of known orbital period of 2.11 d. This type of polarization variability is expected for a binary system with light scattering material distributed symmetrically with respect to the orbital plane. Even though most of the observed polarization ($\sim$2$\%$) is of interstellar origin, about one third of it is due to the intrinsic component. In addition to the regular polarization variability, there is a non-periodic component, strongest in the $B$ passband. We obtained in the $V$ passband our most reliable values for the orbital inclination $i = 46^{\circ}+11^{\circ}/-46^{\circ}$ and the orientation of the orbit on the sky $\Omega = 105^{\circ} \pm 55^{\circ}$, with 1$\sigma$ confidence intervals. The direction of the binary system rotation on the plane of the sky is clockwise

Optical polarization signatures of black hole X-ray binaries

Polarimetry provides an avenue for probing the geometry and physical mechanisms producing optical radiation in many astrophysical objects, including stellar binary systems. We present the results of multiwavelength (BVR) polarimetric studies of a sample of historical black hole X-ray binaries, observed during their outbursts or in the quiescent (or near-quiescent) state. We surveyed both long- and short-period systems, located at different Galactic latitudes. We performed careful analysis of the interstellar polarization in the direction on the sources to reliably estimate the intrinsic source polarization. Intrinsic polarization was found to be small (5 per cent) intrinsic quiescent-state polarization with a blue spectrum. The absence of intrinsic polarization at the optical wavelengths puts constraints on the potential contribution of non-stellar (jet, hot flow, accretion disc) components to the total spectra of black hole X-ray binaries

The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019

Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe

The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050: a systematic analysis for the Global Burden of Disease Study 2021

This online publication has been corrected. The corrected version first appeared at thelancet.com on September 28, 2023BACKGROUND : Diabetes is one of the leading causes of death and disability worldwide, and affects people regardless of country, age group, or sex. Using the most recent evidentiary and analytical framework from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), we produced location-specific, age-specific, and sex-specific estimates of diabetes prevalence and burden from 1990 to 2021, the proportion of type 1 and type 2 diabetes in 2021, the proportion of the type 2 diabetes burden attributable to selected risk factors, and projections of diabetes prevalence through 2050. METHODS : Estimates of diabetes prevalence and burden were computed in 204 countries and territories, across 25 age groups, for males and females separately and combined; these estimates comprised lost years of healthy life, measured in disability-adjusted life-years (DALYs; defined as the sum of years of life lost [YLLs] and years lived with disability [YLDs]). We used the Cause of Death Ensemble model (CODEm) approach to estimate deaths due to diabetes, incorporating 25 666 location-years of data from vital registration and verbal autopsy reports in separate total (including both type 1 and type 2 diabetes) and type-specific models. Other forms of diabetes, including gestational and monogenic diabetes, were not explicitly modelled. Total and type 1 diabetes prevalence was estimated by use of a Bayesian meta-regression modelling tool, DisMod-MR 2.1, to analyse 1527 location-years of data from the scientific literature, survey microdata, and insurance claims; type 2 diabetes estimates were computed by subtracting type 1 diabetes from total estimates. Mortality and prevalence estimates, along with standard life expectancy and disability weights, were used to calculate YLLs, YLDs, and DALYs. When appropriate, we extrapolated estimates to a hypothetical population with a standardised age structure to allow comparison in populations with different age structures. We used the comparative risk assessment framework to estimate the risk-attributable type 2 diabetes burden for 16 risk factors falling under risk categories including environmental and occupational factors, tobacco use, high alcohol use, high body-mass index (BMI), dietary factors, and low physical activity. Using a regression framework, we forecast type 1 and type 2 diabetes prevalence through 2050 with Socio-demographic Index (SDI) and high BMI as predictors, respectively. FINDINGS : In 2021, there were 529 million (95% uncertainty interval [UI] 500–564) people living with diabetes worldwide, and the global age-standardised total diabetes prevalence was 6·1% (5·8–6·5). At the super-region level, the highest age-standardised rates were observed in north Africa and the Middle East (9·3% [8·7–9·9]) and, at the regional level, in Oceania (12·3% [11·5–13·0]). Nationally, Qatar had the world’s highest age-specific prevalence of diabetes, at 76·1% (73·1–79·5) in individuals aged 75–79 years. Total diabetes prevalence—especially among older adults—primarily reflects type 2 diabetes, which in 2021 accounted for 96·0% (95·1–96·8) of diabetes cases and 95·4% (94·9–95·9) of diabetes DALYs worldwide. In 2021, 52·2% (25·5–71·8) of global type 2 diabetes DALYs were attributable to high BMI. The contribution of high BMI to type 2 diabetes DALYs rose by 24·3% (18·5–30·4) worldwide between 1990 and 2021. By 2050, more than 1·31 billion (1·22–1·39) people are projected to have diabetes, with expected age-standardised total diabetes prevalence rates greater than 10% in two super-regions: 16·8% (16·1–17·6) in north Africa and the Middle East and 11·3% (10·8–11·9) in Latin America and Caribbean. By 2050, 89 (43·6%) of 204 countries and territories will have an age-standardised rate greater than 10%. INTERPRETATION : Diabetes remains a substantial public health issue. Type 2 diabetes, which makes up the bulk of diabetes cases, is largely preventable and, in some cases, potentially reversible if identified and managed early in the disease course. However, all evidence indicates that diabetes prevalence is increasing worldwide, primarily due to a rise in obesity caused by multiple factors. Preventing and controlling type 2 diabetes remains an ongoing challenge. It is essential to better understand disparities in risk factor profiles and diabetes burden across populations, to inform strategies to successfully control diabetes risk factors within the context of multiple and complex drivers.Bill & Melinda Gates Foundation.http://www.thelancet.comam2024School of Health Systems and Public Health (SHSPH)SDG-03:Good heatlh and well-bein

An Introduction to iPhone Hardware, Operating System, Applications and Development of iPhone Applications

The aim of this thesis work is to discuss the newly popular mobile phone device named iPhone made by Apple Inc, iPhone operating system and iPhone Applications. Apple iPhone has recently become extremely popular and just within two years of its launch it has captured millions of customers around the world. Thousands of developers have been developing all kinds of mobile phone applications for iPhone and a new era of mobile phone applications development has started. Augmented reality applications on iPhone have really changed the ways that a mobile phone device can be used. This thesis work will find out that what kind of applications can be developed for Finnish iPhone users and for this purpose an iPhone application is developed that shows the timetable of Turku city buses

Investigation of Project Delays: Towards a Sustainable Construction Industry

The construction industry is one of the key industries for any country. It has been observed that this industry is suffering from sustainable solutions during project execution. It is evident from the literature that most of the construction projects are seriously affected by delays. Pakistan’s construction industry also suffers similar challenges. After the COVID-19 pandemic, the construction industry is experiencing several challenges which have resulted in project delays. Thus, this study investigates the key challenges affecting the timely completion of construction projects. The challenges were discovered from the literature and investigated to analyze their significance towards a sustainable construction project. This study also observes the relationships between the key challenges using Partial Least Squares Structural Equation Modeling (PLS-SEM). A structural model was developed based on the 55 common challenges identified from literature. Data collection was administered through a structured questionnaire survey using a 5-point Likert-scale. The challenges were grouped into six constructs. The outcome reported 20 critical challenges, with information and communication-related factors being the most important challenge in the construction industry. Contract management also significantly affects project time overrun. The created model served as a starting point for academics, researchers, and practitioners to create an effective system for regulating time overrun challenges

Optical polarization signatures of black hole X-ray binaries

Polarimetry provides an avenue for probing the geometry and physical mechanisms producing optical radiation in many astrophysical objects, including stellar binary systems. We present the results of multiwavelength (BVR) polarimetric studies of a sample of historical black hole X-ray binaries, observed during their outbursts or in the quiescent (or near-quiescent) state. We surveyed both long- and short-period systems, located at different Galactic latitudes. We performed careful analysis of the interstellar polarization in the direction on the sources to reliably estimate the intrinsic source polarization. Intrinsic polarization was found to be small (< 0.2 per cent) in sources observed in bright soft states (MAXI J0637-430 and 4U 1957+115). It was found to be significant in the rising hard state of MAXI J1820+070 at the level of 0.5 per cent and negligible in the decaying hard state and during its failed outbursts, while Swift J1357.2-0933 showed its absence in the rising hard state. Three (XTE J1118+480, V4641 Sgr, V404 Cyg) sources observed during quiescence show no evidence of significant intrinsic polarization, while MAXI J1820+070 is the only black hole X-ray binary which showed substantial (> 5 per cent) intrinsic quiescent-state polarization with a blue spectrum. The absence of intrinsic polarization at the optical wavelengths puts constraints on the potential contribution of non-stellar (jet, hot flow, accretion disc) components to the total spectra of quiescent black hole X-ray binaries