Trajectory of light ray slightly above the equatorial plane in Kerr geometry and its deflection

2017 ◽  
Vol 95 (12) ◽  
pp. 1307-1312 ◽  
Author(s):  
Sarani Chakraborty ◽  
A.K. Sen
Keyword(s):  
Impact Parameter ◽  
Equatorial Plane ◽  
Deflection Angle ◽  
Kerr Geometry ◽  
The Past ◽  
The Impact ◽  
Analytical Expressions ◽  
Made In

Deflection angle for a light ray travelling in the equatorial plane of a rotating Kerr mass has been calculated in the past by various investigators. Considering the light ray to be travelling only slightly above the equatorial plane, calculations have been made in the present paper for such a ray’s deflection angle. We calculate deflection angles for the light ray at various heights above the equatorial plane, which are small compared to the impact parameter and derive corresponding analytical expressions for deflection angle.

glass, Roman

2016 ◽  
Author(s):  
H.E.M. Cool
Keyword(s):  
New Technologies ◽  
Window Glass ◽  
Interior Decoration ◽  
The Past ◽  
Imperial Period ◽  
Roman Glass ◽  
Considerable Debate ◽  
Competing Models ◽  
The Impact ◽  
Made In

Glass came of age during the Roman period. Within the ancient world it had been used from the mid-second millennium bce onwards, but only for jewellery and luxury items like small perfume bottles. This started to change in the late 2nd century bce, when the Hellenistic industries started to produce simple glass drinking vessels. In the early Imperial period there was an explosion in the vessel forms available, in part made possible by the discovery of how to blow glass. The new types included both the luxurious, such as exquisite cameo vessels, and the utilitarian, such as disposable packaging for cosmetics. A similar expansion was seen in its role in buildings, where glass went from luxurious interior decoration to structurally important window glass. References in literary works and depictions in wall paintings at the time attest to the considerable attention this new phenomenon attracted in the early to mid-1st century ce. Vessels, windows and other items spread widely throughout the empire and beyond, and to all levels of society. Over the next 400 years, how the material was used changed with time and place as the various regional industries responded to the needs and preferences of their communities. This was a major high-temperature industry which would have made considerable demands on resources such as fuel, but there are still many things that are unknown about it. Where, for example, was the glass itself made? Waste from secondary workshops producing vessels is regularly encountered, but evidence for the primary production is extremely rare. This has led to considerable debate, with competing models being proposed. Glass is not a material where scientific techniques such as those used to provenance pottery have proved very helpful. The composition of Roman glass is extremely uniform throughout the empire, and again there has been much debate about why this might be. Of late, some useful advances have started to be made in approaching these questions, and this may eventually disentangle what was going on. The study of Roman glass provides a unique window into the past. Through it the impact of new technologies and materials can be seen, as well as the choices people made about what was useful in their lives—all against the background of some of the most beautiful and skilful vessels ever made.

scholarly journals Sciences and audiences along the last century: the impact of Astronomy Education

2018 ◽  
Vol 13 (S349) ◽  
pp. 474-478
Author(s):  
Rosa M. Ros ◽  
Beatriz Garca
Keyword(s):  
Secondary Teachers ◽  
Astronomy Education ◽  
Interest In Science ◽  
The Past ◽  
The World ◽  
History Of ◽  
The Impact ◽  
Made In ◽  
Science Activities

AbstractJust as in the past, the development of the natural sciences and in particular of astronomy has changed the history of humanity. If we think about the role of our discipline into the future, it shows its enormous power in the field of education, owing to the possibility of awakening interest in science in very varied audiences. Within the framework of the enormous progress made in the technologies related to astronomy, many of them of daily use, the role of the astronomer in the era of Communications acquires fundamental importance.In this presentation, we will try to make a journey through the different ways of presenting astronomical topics for different audiences over the last 100 years. In turn, we will show some specific achievements, associated with education programmes of the discipline. We discuss the impact produced by proposals that are both rigorous in terms of content, and also appeal to the development of the human being in an integral manner, within the framework of citizen science activities.For this research, we have taken into account the uninterrupted development of the NASE programme, which has performed 112 courses in 24 countries throughout the world and in different languages. NASE has involved 4966 secondary teachers in the last eight years.

scholarly journals Lattice QCD input for nuclear structure and reactions

2018 ◽  
Vol 175 ◽  
pp. 01022 ◽  
Author(s):  
Zohreh Davoudi
Keyword(s):  
Quantum Chromodynamics ◽  
Nuclear Reactions ◽  
Many Body ◽  
Quark Masses ◽  
The Past ◽  
Lattice Quantum ◽  
Nuclear Systems ◽  
Community Effort ◽  
The Impact ◽  
Made In

Explorations of the properties of light nuclear systems beyond their lowestlying spectra have begun with Lattice Quantum Chromodynamics. While progress has been made in the past year in pursuing calculations with physical quark masses, studies of the simplest nuclear matrix elements and nuclear reactions at heavier quark masses have been conducted, and several interesting results have been obtained. A community effort has been devoted to investigate the impact of such Quantum Chromodynamics input on the nuclear many-body calculations. Systems involving hyperons and their interactions have been the focus of intense investigations in the field, with new results and deeper insights emerging. While the validity of some of the previous multi-nucleon studies has been questioned during the past year, controversy remains as whether such concerns are relevant to a given result. In an effort to summarize the newest developments in the field, this talk will touch on most of these topics.

The Potential for Immersive Technology combined with Online Dating

2017 ◽  
Vol 5 (4) ◽  
pp. 125-135
Author(s):  
David Evans Bailey
Keyword(s):  
Online Dating ◽  
Digital Economy ◽  
The Past ◽  
The Future ◽  
The Impact ◽  
Immersive Technology ◽  
Made In ◽  
Immersive Technologies ◽  
The Way

Whilst online dating has been around for several years; immersive technologies are relatively new to this type of interaction. The first forays into immersive VR online dating have only just being made in the past year. To what degree this type of technology will change the way that we date is potentially quite different from the current way that online dates are conducted. The way the technology works could make virtual dates seem as real as a physical date. Understanding how immersive technology functions gives some insights into the future of online dating and also the impact on the digital economy.

Towards a better understanding of past fertility regimes: the ideas and practice of controlling family size in Chinese history

2006 ◽  
Vol 21 (1) ◽  
pp. 9-35 ◽  
Author(s):  
ZHONGWEI ZHAO
Keyword(s):  
Family Size ◽  
Reproductive Behaviour ◽  
Population History ◽  
High Fertility ◽  
Chinese History ◽  
Traditional Beliefs ◽  
The Past ◽  
Demand For Children ◽  
The Impact ◽  
Made In

Thanks to the progress that has been made in the study of population history, it has been gradually accepted that fertility in historical China was only moderate in comparison with the recorded high fertility. However, scholars still disagree on whether the Chinese could have intentionally controlled their family size. This article first summarizes recent findings about fertility patterns in historical China. Then the author provides further evidence of people limiting their family size in the past, before discussing the impact of traditional beliefs on people's fertility behaviour and summarizing the antinatalist ideas and suggestions put forwarded by Chinese officials and intellectuals over China's long history. This evidence is then used to comment on a number of suggestions that have been made about China's traditional reproductive behaviour and culture. The article challenges the views that people's reproductive strategies aimed in the past to maximize the number of surviving offspring and that the demand for children (or sons) was always high in historical China.

scholarly journals Study of the Irradiation Damage in Simple Crystals by Channeling

2019 ◽  
Vol 7 ◽  
pp. 163
Author(s):  
M. Kokkoris ◽  
H. Huber ◽  
S. Kossionides ◽  
T. Paradellis ◽  
Ch. Zarkadas ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Maximum Dose ◽  
High Energy ◽  
Irradiation Damage ◽  
Progressive Change ◽  
The Past ◽  
Random Direction ◽  
The Impact ◽  
Made In

Several experiments have been carried out in the past in order to examine the impact of medium and heavy ions in crystals in the MeV range, which is of particular interest in high energy implantations. In the present work, the gradual amorphisation of simple crystals such as Si (100), Ge (100) and W (100) when irradiated with 18 MeV 1 6 0 in a random direction is being studied using the progressive change of channeling parameters, up to a maximum dose of approximately 1Ί01 6 par tides/en*2. The results are compared to the ones present in literature and an attempt is made in order to explain the peculiarities of the experimental spectra.

Gene Therapy for Hemophilia: a review on clinical benefit, limitations and remaining issues

Blood ◽  
2021 ◽  
Author(s):  
Frank W.G. Leebeek ◽  
Wolfgang Miesbach
Keyword(s):  
Gene Therapy ◽  
Clinical Benefit ◽  
Hemophilia A ◽  
Phase 1 ◽  
Successful Outcome ◽  
Severe Hemophilia ◽  
The Past ◽  
Therapy Studies ◽  
The Impact ◽  
Made In

In the past decade enormous progress has been made in the development of gene therapy for hemophilia A and B. After the first encouraging results of intravenously administered AAV-based liver-directed gene therapy in patients with severe hemophilia B were reported in 2011, many gene therapy studies have been initiated. Most of these studies, using AAV vectors with various gene constructs, showed sufficient FVIII and FIX expression in patients to significantly reduce the number of bleeds and the need for prophylaxis in the fast majority of the severe hemophilia patients. This resulted in great clinical benefit for nearly all patients. In this review we will summarize the most recent findings of reported and ongoing gene therapy trials. We will highlight the successful outcome of trials with focus on the results of recently reported phase 1 trials and preliminary results of phase 2b/3 trials for hemophilia A and B. These new reports also reveal the impact of side effects and drawbacks associated with gene therapy. We will therefore also discuss the limitations and remaining issues of the current gene therapy approaches. These issues have to be resolved before gene therapy will be widely available for the hemophilia patient population.

scholarly journals A fully general, non-perturbative treatment of impulsive heating

2021 ◽  
Vol 502 (1) ◽  
pp. 1441-1455
Author(s):  
Uddipan Banik ◽  
Frank C van den Bosch
Keyword(s):  
Impact Parameter ◽  
Equal Mass ◽  
Astrophysical Objects ◽  
The Subject ◽  
Impulsive Heating ◽  
The Moment ◽  
Quadrupole Term ◽  
The Impact ◽  
Analytical Expressions ◽  
Perturbative Treatment

ABSTRACT Impulsive encounters between astrophysical objects are usually treated using the distant tide approximation (DTA) for which the impact parameter, b, is assumed to be significantly larger than the characteristic radii of the subject, rS, and the perturber, rP. The perturber potential is then expanded as a multipole series and truncated at the quadrupole term. When the perturber is more extended than the subject, this standard approach can be extended to the case where rS ≪ b < rP. However, for encounters with b of order rS or smaller, the DTA typically overpredicts the impulse, Δv, and hence the internal energy change of the subject, ΔEint. This is unfortunate, as these close encounters are the most interesting, potentially leading to tidal capture, mass stripping, or tidal disruption. Another drawback of the DTA is that ΔEint is proportional to the moment of inertia, which diverges unless the subject is truncated or has a density profile that falls off faster than r−5. To overcome these shortcomings, this paper presents a fully general, non-perturbative treatment of impulsive encounters which is valid for any impact parameter, and not hampered by divergence issues, thereby negating the necessity to truncate the subject. We present analytical expressions for Δv for a variety of perturber profiles, apply our formalism to both straight-path encounters and eccentric orbits, and discuss the mass-loss due to tidal shocks in gravitational encounters between equal-mass galaxies.

scholarly journals Testing Einstein’s formula for gravitational deflection of light based on lightcurves of microlensed sources

2019 ◽  
pp. 16-20
Author(s):  
A.N. Alexandrov ◽  
V.I. Zhdanov ◽  
V.M. Sliusar
Keyword(s):  
Impact Parameter ◽  
Deflection Angle ◽  
Light Deflection ◽  
Classical Formula ◽  
Deflection Of Light ◽  
Gravitational Deflection Of Light ◽  
The Deflection Angle ◽  
The Impact ◽  
Gravitational Deflection

We propose a new test of the Einstein’s formula for the gravitational light deflection using the Galactic microlensing. In this classical formula, the deflection angle ∆ϕ is inversely proportional to the impact parameter p of incoming photons travelling from infinity.

Coalbed Methane: Current Field-Based Evaluation Methods

2011 ◽  
Vol 14 (01) ◽  
pp. 60-75 ◽  
Author(s):  
C.R.. R. Clarkson ◽  
R.M.. M. Bustin
Keyword(s):  
Relative Permeability ◽  
Coalbed Methane ◽  
Material Balance ◽  
Gas Content ◽  
Absolute Permeability ◽  
Accurate Estimation ◽  
Reservoir Properties ◽  
The Past ◽  
The Impact ◽  
Made In

Summary Coalbed methane (CBM) produced from subsurface coal deposits has been produced commercially for more than 30 years in North America, and relatively recently in Australia, China, and India. Historical challenges to predicting CBM-well performance and long-term production have included accurate estimation of gas in place (including quantification of in-situ sorbed gas storage); estimation of initial fluid saturations (in saturated reservoirs) and mobile water in place; estimation of the degree of undersaturation (undersaturated coals produce mainly water above desorption pressure); estimation of initial absolute permeability (system); selection of appropriate relative permeability curves; estimation of absolute-permeability changes as a function of depletion; prediction of produced-gas composition changes as a function of depletion; accounting for multilayer behavior; and accurate prediction of cavity or hydraulic-fracture properties. These challenges have primarily been a result of the unique reservoir properties of CBM. Much progress has been made in the past decade to evaluate fundamental properties of coal reservoirs, but obtaining accurate estimates of some basic reservoir and geomechanical properties remains challenging. The purpose of the current work is to review the state of the art in field-based techniques for CBM reservoir-property and stimulation-efficiency evaluation. Advances in production and pressure-transient analysis, gas-content determination, and material-balance methods made in the past 2 decades will be summarized. The impact of these new methods on the evaluation of key reservoir properties, such as absolute/relative permeability and gas content/gas in place, as well as completion/stimulation properties will be discussed. Recommendations on key surveillance data to assist with field-based evaluation of CBM, along with insight into practical usage of these data, will be provided.

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