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We compute general-relativistic polytropic models of differentially rotating neutron stars. A brief description of our numerical treatment is given as follows. First, the relativistic Oppenheimer–Volkoff equations of hydrostatic equilibrium are solved for nonrotating models obeying the well-known polytropic equation of state. Then, uniform rotation assumed for such models is treated in the framework of Hartle's perturbation method; thus, corrections to mass and radius, owing to spherical and quadrupole deformations, are calculated. Next, a perturbative approach to the stellar structure up to terms of third order in the angular velocity is carried out; angular momentum, J, moment of inertia, I, rotational kinetic energy, T, and gravitational potential energy, W, are quantities drastically corrected by the third-order approach. Finally, assuming that our polytropic models satisfy a particular differential rotation law, we compute the increase in mass and in some other significant physical characteristics owing to the differential rotation.

We review the general properties of the intracluster medium (ICM) in clusters that host a cooling flow, and in particular the effects on the ICM of the injection of hot plasma by a powerful active galactic nucleus (AGN). It is observed that, in some cases, the hot plasma produces cavities in the ICM that finally detach and rise, perhaps buoyantly. The gas dynamics induced by the rising bubbles can help in explaining the absence of a cooled gas component in clusters with a cooling flow. This scenario is explored using numerical simulations.

Design plays a key role in the development of software. The quality of design is crucial and is a fundamental decision element in assessing the software product. The early availability of design quality evaluation provides a better way to decide the quality of the final product. This avoids presumption in the quality evaluation process. Hence Software Metrics provide a valuable and objective insight of enhancing each of the software quality characteristics. This paper proposes a quality model to assess the design phase of any object-oriented system based on the works of Chidamber, Kemrer and Basili and suggests two new metrics. The research focuses on analyzing a set of metrics, which has direct influence on the quality of the software and creating a metrics tool based on Java that can be used to validate the object-oriented projects against these metrics. The analysis is carried out on a set of real world projects designed using Unified Modeling Language, which are used as test cases. These metrics and models are proposed to add more quality information in refining any object-oriented system during the early stages of design itself.

By using cluster analysis, we select a galaxy pair sample in the Sloan Great Wall and study its various properties. We find that in the Sloan Great Wall pair sample, most galaxies are brighter and smaller, and that there is a tendency for pair galaxies to have similar luminosity and size.

In this paper, we will show how the statistics of the gravitational field is changed when the system is characterized by a non-uniform distribution of particles. We will show how the distribution functions W(F) and W(F,dF/dt), giving the joint probability that a test particle is subject to a force F and an associated rate of change of F given by dF/dt, are modified by inhomogeneity. Then we will calculate the first moment of dF/dt to study the effects of inhomogenity on dynamical friction. Finally we will test, by N-Body simulations, that the theoretical W(F) and dF/dt describes correctly the experimental data and we find that the stochastic force distribution obtained for the evolved system is in good agreement with theory. Moreover, we find that in an inhomogeneous background, the friction force is actually enhanced relative to the homogeneous case.

We present the analysis of the quadrupole phases of the Internal Linear Combination map, ILC(I) and (III), derived by the WMAP team (one- and three-year data release). This approach allows us to see the global trend of non-Gaussianity of the quadrupoles for the ILC(III) map through phase correlations with the foregrounds. Significant phase correlations are found between the ILC(III) quadrupole and the WMAP foreground phases for the K-W band: the phases of the ILC(III) quadrupole ξ_2,1, ξ_2,2 and those of the foregrounds at K–W bands Φ_2,1, Φ_2,2 display significant symmetry: ξ_2,1 + Φ_2,1 ≃ ξ_2,2 + Φ_2,2, which is a strong indication that the morphology of the ILC(III) quadrupole is a mere reflection of that the foreground quadrupole through coupling. To clarify this issue we exploit the symmetry of the CMB power, which is invariant under permutation of the index m = 1 ⇔ 2. By simple rotation of the ILC(III) phases with the same angle we reach the phases of the foreground quadrupole. We discuss possible sources of phase correlation and come to the conclusion that the phases of the ILC(III) quadrupole reflect most likely systematic effects such as changing of the gain factor for the three-year data release with respect to the one-year, rather than manifestation of the primordial non-Gaussianity.

The theory of the post-Newtonian (PN) planar circular restricted three-body problem is used for numerically investigating the orbital dynamics of a test particle (e.g. a comet, asteroid, meteor or spacecraft) in the planar Sun–Jupiter system with a scattering region around Jupiter. For determining the orbital properties of the test particle, we classify large sets of initial conditions of orbits for several values of the Jacobi constant in all possible Hill region configurations. The initial conditions are classified into three main categories: (i) bounded, (ii) escaping and (iii) collisional. Using the smaller alignment index (SALI) chaos indicator, we further classify bounded orbits into regular, sticky or chaotic. In order to get a spherical view of the dynamics of the system, the grids of the initial conditions of the orbits are defined on different types of two-dimensional planes. We locate the different types of basins and we also relate them with the corresponding spatial distributions of the escape and collision time. Our thorough analysis exposes the high complexity of the orbital dynamics and exhibits an appreciable difference between the final states of the orbits in the classical and PN approaches. Furthermore, our numerical results reveal a strong dependence of the properties of the considered basins with the Jacobi constant, along with a remarkable presence of fractal basin boundaries. Our outcomes are compared with the earlier ones regarding other planetary systems.

In this paper, we explore the self-similarity time evolution of a hot accretion flow around a compact object in the presence of a toroidal magnetic field. We focus on a simplified model which is axisymmetric, rotating, unsteady viscous-resistive under an advection-dominated stage. In this work, we suppose that both the kinematic viscosity and the magnetic diffusivity to be a result of turbulence in the accretion flow. To describe such a flow, we apply magneto-hydrodynamics equations in spherical coordinates, $(r,𝜃,\phi )$ and adopt unsteady self-similar solutions. By neglecting the latitudinal dependence of the flow, we obtain a set of one-dimensional differential equations governing the accretion system. In this research, we encounter two parameters related to the magnetic field; one of them is, $\beta$, defined as the ratio of the magnetic pressure to the gas pressure and the other one, ${\mathrm{\Gamma }}_0$ applied in the magnetic diffusivity definition. Our results show that $\beta$ is a function of position, and increases towards outer layers. On the other hand, we examine different strength of magnetic field by choosing different value of ${\beta }_0$ which is the value of $\beta$ at the inner edge of disc. We see that both ${\beta }_0$ and ${\mathrm{\Gamma }}_0$ have positive effect on growing the radial infall velocity but density and gas pressure decrease by larger values of these parameters. Moreover, the rotational velocity and temperature of accreting material reduce considerably under the influence of a stronger magnetic field. We also focus on the behavior of the mass accretion rate appearing as a descending function of position. Finally, our solutions confirm that the radial trend of the physical quantities in a dynamical accretion flow is different from the ones in a steady flow. However, the effect of various parameters on the physical quantities in our model is qualitatively consistent with similar steady models.

One of the most significant discoveries in modern cosmology is that the universe is currently in a phase of accelerated expansion after a switch from a decelerated expansion. The redshift corresponding to this epoch is commonly referred to as the transition redshift $z_t$. In this work, we put constraints on the transition redshift with both model-independent and model-dependent approaches. We consider the recently compiled database of 32 Hubble parameter measurements and the Pantheon sample of Type Ia Supernovae (SNe). In order to include the possible systematic effects in this analysis, we use the full covariance matrix of systematic uncertainties for the Hubble parameter measurements. We plot a Hubble Phase Space Portrait (HPSP) between $Ḣ(z)$ and $H(z)$ in a model-independent way. From this HPSP diagram, we estimate the transition redshift as well as the current value of the equation of state parameter ${\omega }_0$ in a model-independent way. By considering H(z) measurements, we find the best fit value of $z_t=0.591_{-0.332}^{+0.332}$ and ${\omega }_0=-0.677_{-0.238}^{+0.238}$. We obtain the best fit value of $z_t=0.849_{-0.117}^{+0.117}$ and ${\omega }_0=-0.870_{-0.013}^{+0.013}$ using the Pantheon database. Further, we also use a model-dependent approach to determine $z_t$. Here, we consider a nonflat $\mathrm{\Lambda }$CDM model as a background cosmological model. We reconstruct the cosmic triangle plot among $log({\mathrm{\Omega }}_{m0})$, $-log(2{\mathrm{\Omega }}_{\mathrm{\Lambda }0})$ and $3log(1+z_t),$ where the constraints of each parameter are determined by the location in this triangle plot. By using ${\mathrm{\Omega }}_{m0}$ and ${\mathrm{\Omega }}_{\mathrm{\Lambda }0}$ values, we find the best value of the transition redshift $z_t=0.619_{-0.758}^{+0.580}$, which is in good agreement with the Planck 2018 results at $1\sigma$ confidence level. We also simulate the observed Hubble parameter measurements in the redshift range $0<z<2$ and perform the same analysis to estimate the transition redshift.

The article is about retinal photography and stroke risk prediction. It is an analysis of the study data that revealed a statistically significant correlation between the presence of retinal microvascular lesions and the occurrence of stroke.

This paper presents a brief overview of intellectual property rights and the various areas in proteomics to which IP rights may be applicable. Technology transfer, including licensing and business agreements, is not covered in this paper. Instead, issues and complications that are related to national and overseas patent prosecution in this relatively new field would be discussed.

Entrepreneurship research has been criticized for a lack of methodological rigor, although evidence suggests that from a methodological perspective, it is improving (Davidsson, 2006). In this paper, we systematically review the methods used in the study of nascent entrepreneurs to identify challenges associated with the data used in these studies. We also review the field's achievements — notably, the successful use of representative sampling of populations of nascent entrepreneurs — and we raise concerns about the predominant use of secondary data sets and the use of scales originally developed for large, established firms. Drawing on methodological advancements in other fields, we offer suggestions related to study design, data collection, sampling and measurement. Although some of the challenges we note are inherent to the nature of entrepreneurship, we hope our discussion can help researchers design better studies and better interpret their findings.

Considerable attention has been given to the role of strategic environmental assessment (SEA) in policy, plan and program assessment; however, there is very little consensus on an appropriate methodology for SEA. Two basic perspectives on SEA methodology emerge from the literature: first, that appropriate SEA methodologies are readily available based on the application of project-level EIA approaches to strategic assessment questions and second, that SEA requires a different, more broad-brush approach than project-level EIA. If SEA is to advance in application and effectiveness, then appropriate SEA methodologies need to be established. Despite calls for SEA to develop more independently of project-level assessment, existing SEA methodologies tend to be based on project-level EIA principles. It is argued here that while SEA can perhaps utilise many of the existing methods from project-level EIA, it requires a different, more broad-brush, but structured methodological approach. This paper reviews the current state-of-the-art of SEA methodology, and presents a generic SEA methodological framework and example based on the notion of the "best practicable environmental option".

Engineering complex biological structures for regenerative medicine, in vitro tissue analysis, and pharmaceutical testing require new fabrication techniques that can place specific cells in specific target locations. Conventional cell seeding methods cannot achieve this level of spatial resolution. Biofabrication is a rapidly advancing field that uses a variety of delivery mechanisms to achieve the spatial resolution necessary to place cells, biomaterials, and bioactive macromolecules in specific target locations. One new technique within this field is bioprinting, which uses drop-on-demand delivery mechanisms to fabricate biological structures. This review focuses on drop-on-demand inkjet bioprinting and provides a primer for researchers seeking to enter the field.

Tata Institute of Fundamental Research (TIFR) Near Infrared Imaging Camera-II (TIRCAM2) is a closed-cycle Helium cryo-cooled imaging camera equipped with a Raytheon 512$\times$512 pixels InSb Aladdin III Quadrant focal plane array (FPA) having sensitivity to photons in the 1–5$\mu \text{m}$ wavelength band. In this paper, we present the performance of the camera on the newly installed 3.6m Devasthal Optical Telescope (DOT) based on the calibration observations carried out during 2017 May 11–14 and 2017 October 7–31. After the preliminary characterization, the camera has been released to the Indian and Belgian astronomical community for science observations since 2017 May. The camera offers a field-of-view (FoV) of $\sim 86.5^{\prime \prime }\times 86.5^{\prime \prime }$ on the DOT with a pixel scale of 0.169${}^{\prime \prime }$. The seeing at the telescope site in the near-infrared (NIR) bands is typically sub-arcsecond with the best seeing of $\sim 0.45^{\prime \prime }$ realized in the NIR $K$-band on 2017 October 16. The camera is found to be capable of deep observations in the $J$, $H$ and $K$ bands comparable to other 4m class telescopes available world-wide. Another highlight of this camera is the observational capability for sources up to Wide-field Infrared Survey Explorer (WISE) W1-band (3.4$\mu$m) magnitudes of 9.2 in the narrow $L$-band ($nbL$; ${\lambda }_{\mathrm{\text{cen}}}\sim$ 3.59$\mu$m). Hence, the camera could be a good complementary instrument to observe the bright $nbL$-band sources that are saturated in the Spitzer-Infrared Array Camera (IRAC) ([3.6] $\lesssim$ 7.92 mag) and the WISE W1-band ([3.4] $\lesssim$ 8.1 mag). Sources with strong polycyclic aromatic hydrocarbon (PAH) emission at 3.3$\mu$m are also detected. Details of the observations and estimated parameters are presented in this paper.

Modern radio astronomical facilities are able to detect extremely weak electromagnetic signals not only from the universe but also from man-made radio frequency interference of various origins. These range from wanted signals to unwanted out-of-band emission of radio services and applications to electromagnetic interference produced by all kinds of electronic and electric devices. Energy harvesting wind turbines are not only equipped with electric power conversion hardware but also copious amounts of electronics to control and monitor the turbines. A wind turbine in the vicinity of a radio telescope could therefore lead to harmful interference, corrupting the measured astronomical data. Many observatories seek to coordinate placement of new wind farms with wind turbine manufacturers and operators, as well as with the local planning authorities, to avoid such a situation. In our study, we provide examples as well as guidelines for the determination of the separation distances between wind turbines and radio observatories, to enable a benign co-existence for both.

The proposed calculations entail three basic steps. At first, the anticipated maximum emitted power level based on the European EN 550011 (CISPR, 2015) standard, which applies to industrial devices, is determined. Then secondly, the propagation loss along the path to the radio receiver is computed via a model provided by the international telecommunication union. Finally, the received power is compared to the permitted power limit that pertains in the protected radio astronomical observing band under consideration. This procedure may be carried out for each location around a telescope site, in order to obtain a map of potentially problematic wind turbine positions.

This paper presents an observing methodology for calibrated measurements of radio interference levels and compares these with threshold interference limits that have been established for interference entering the bands allocated to the Radio Astronomy Service. The measurement time and bandwidth intervals for these observations may be commensurate with the time and frequency variability characteristic of the interfering signals and the threshold levels may be appropriately scaled from the values presented in ITU-R RA.769 using a 2000s reference time interval. The data loss for astronomical instruments may be measured as a percentage of occupancy in the time–frequency domain both for short and long measurement intervals. The observed time–frequency occupancy characteristics for non-geostationary satellite systems and earth stations in the mobile–satellite service may be incorporated into an effective power flux density simulation to obtain the effective data loss and sky blockage due to these services.

Distance measurement is crucial to astronomy. Here, we suggest a new conceptual method to measure the distance by using a local instrument. By engaging the double-slit interference and by considering the phase information of the light, the position of the intensity maximum is related to the distance of the source. Consequently, the precise measurement of the position can be used to measure the distance of the remote source.

The Mexican Array Radio Telescope (MEXART), located in the state of Michoacan in Mexico, has been operating in an analog fashion, utilizing a Butler Matrix to generate fixed beams on the sky, since its inception. Calibrating this instrument has proved difficult, leading to loss in sensitivity. It was also a rigid setup, requiring manual intervention and tuning for different observation requirements. The Radio Frequency (RF) system has now been replaced with a digital one. This digital backend is a hybrid system utilizing both FPGA-based technology and GPU acceleration, and is capable of automatically calibrating the different rows of the array, as well as generating a configurable number of frequency-domain synthesized beams to towards selected locations on the sky. A monitoring and control system, together with a full-featured web-based front-end, has also been developed, greatly simplifying the interaction with the instrument. This paper presents the design, implementation and deployment of the new digital backend, including preliminary analysis of system performance and stability.

TIRCAM2 is the facility near-infrared Imager at the Devasthal 3.6-m telescope in northern India, equipped with an Aladdin III InSb array detector. We have pioneered the use of TIRCAM2 for very fast photometry, with the aim of recording Lunar Occultations (LO). This mode is now operational and publicly offered. In this paper, we describe the relevant instrumental details, provide references to the LO method and the underlying data analysis procedures, and list the LO events recorded so far. Among the results, we highlight a few which have led to the measurement of one small-separation binary star and of two stellar angular diameters. We conclude with a brief outlook on further possible instrumental developments and an estimate of the scientific return. In particular, we find that the LO technique can detect sources down to $K\approx 9$mag with $\mathrm{\text{SNR}}=1$ on the Devasthal Optical Telescope telescope. Angular diameters larger than $\approx 1$ milliarcsecond (mas) could be measured with SNR above 10, or $K\approx 6$mag. These numbers are only an indication and will depend strongly on observing conditions such as lunar phase and rate of lunar limb motion. Based on statistics alone, there are several thousands LO events observable in principle with the given telescope and instrument every year.