scholarly journals The effect of mission duration on LISA science objectives

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Pau Amaro Seoane ◽  
Manuel Arca Sedda ◽  
Stanislav Babak ◽  
Christopher P. L. Berry ◽  
Emanuele Berti ◽  
...  
Keyword(s):  
Black Holes ◽  
Duty Cycle ◽  
Data Stream ◽  
Continuous Data ◽  
Implicit Assumption ◽  
Mission Duration ◽  
Science Group ◽  
The Impact ◽  
Science Investigations ◽  
Mission Operations

AbstractThe science objectives of the LISA mission have been defined under the implicit assumption of a 4-years continuous data stream. Based on the performance of LISA Pathfinder, it is now expected that LISA will have a duty cycle of $$\approx 0.75$$ ≈ 0.75 , which would reduce the effective span of usable data to 3 years. This paper reports the results of a study by the LISA Science Group, which was charged with assessing the additional science return of increasing the mission lifetime. We explore various observational scenarios to assess the impact of mission duration on the main science objectives of the mission. We find that the science investigations most affected by mission duration concern the search for seed black holes at cosmic dawn, as well as the study of stellar-origin black holes and of their formation channels via multi-band and multi-messenger observations. We conclude that an extension to 6 years of mission operations is recommended.

scholarly journals Bootstrapped Newtonian Cosmology and the Cosmological Constant Problem

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 358
Author(s):  
Roberto Casadio ◽  
Andrea Giusti
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Quantum Cosmology ◽  
Quantum Physics ◽  
Gravitational Interaction ◽  
Newtonian Gravity ◽  
Cosmological Constant Problem ◽  
Newtonian Cosmology ◽  
Natural Solution ◽  
The Impact

Bootstrapped Newtonian gravity was developed with the purpose of estimating the impact of quantum physics in the nonlinear regime of the gravitational interaction, akin to corpuscular models of black holes and inflation. In this work, we set the ground for extending the bootstrapped Newtonian picture to cosmological spaces. We further discuss how such models of quantum cosmology can lead to a natural solution to the cosmological constant problem.

scholarly journals X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

2019 ◽  
Vol 15 (S356) ◽  
pp. 143-143
Author(s):  
Jaya Maithil ◽  
Michael S. Brotherton ◽  
Bin Luo ◽  
Ohad Shemmer ◽  
Sarah C. Gallagher ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Time Lags ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
X Ray ◽  
Photon Index ◽  
The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

Quantifying Office Productivity: An Ergonomic Framework

1998 ◽  
Vol 42 (13) ◽  
pp. 974-978 ◽  
Author(s):  
Alan Hedge
Keyword(s):  
Life Cycle ◽  
Duty Cycle ◽  
Office Workers ◽  
Short Term ◽  
Task Time ◽  
Ergonomic Interventions ◽  
The Impact

An ergonomic framework for conceptualizing and measuring office productivity is described. This framework is based on the the analysis of task time, posture and sequence, and the subsequent the determination of the most appropriate pace, posture, and activities for any office job. The framework assesses various measures of pace, proficiency, and posture that currently can be readily assessed by ergonomists, and it uses these measures to quantify the short-term duty cycle productivity (DCP) and in the longer-term life-cycle productivity (LCP) of office workers. The approach that will be described allows companies to evaluate the impact of ergonomic interventions on the productivity of their workers. The benefits of this ergonomic approach to assessing productivity are discussed.

Research on Mining Technology of Communication Data Stream Based on Computer Network Multimedia

2013 ◽  
Vol 427-429 ◽  
pp. 2094-2098
Author(s):  
Yang Li
Keyword(s):  
Data Stream ◽  
System Analysis ◽  
Data Flow ◽  
Computer Network ◽  
Strong Shock ◽  
Multimedia Communication ◽  
Mining Technology ◽  
The Sustainable Development ◽  
And Performance ◽  
The Impact

According to the application of the computer network multimedia is more and more widely, and is also correspondingly strong shock by the network media and informatization for network communication and other requirements, progress and development of society constantly threatened by the impact of network multimedia communication. The paper theory-based with network multimedia communication to analysis the characteristics and performance requirements of network multimedia communication, combining to relevant material of the data flow, research and analyze the data flow of the mining technology, to carries on system analysis of the data flow, construct system model based on the network multimedia communication data stream, in order to better guide the dynamic analysis to network multimedia communication data flow, to master the multimedia communication data fusion and decision, so as to understand the users needs to network multimedia communication, to better guide the sustainable development of the network multimedia communication.

Exploring Simple Machines With Creative Movement

2020 ◽  
pp. 92-121
Author(s):  
William Paul Lindquist ◽  
Martha James-Hassan ◽  
Nathan C. Lindquist
Keyword(s):  
Science Content ◽  
Creative Movement ◽  
Urban Elementary School ◽  
Simple Machines ◽  
Movement Strategy ◽  
Core Idea ◽  
Past Experiences ◽  
Unit Plan ◽  
The Impact ◽  
Science Investigations

This chapter explores the use of creative movement to extend meaning to inquiry-based science investigations. This process embraces the addition of A to STEM to realize the impact of STEAM. The chapter builds on the import of scientific and physical literacy, interdisciplinary learning, and the power of kinesthetic engagement. Students become active collaborative agents within a dynamic model using creative movement to bring meaning to the science of simple machines. The authors utilize working words into movement strategy to help students use their past experiences and motor memory to explore, interpret, and engage with as they seek understanding of simple machines. A Midwest urban elementary school provides the context for a unit plan culminating in a dance performance. The foundational ideas presented within this unit can be enacted within any classroom by creative movement (physical education or dance) specialists, science specialists, or classroom generalists. It follows with a presentation of science content on simple machines exploring the disciplinary core idea of force and motion.

Dynamical versus isolated formation channels of gravitational wave sources

2018 ◽  
Vol 14 (S346) ◽  
pp. 397-416
Author(s):  
Michela Mapelli
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Theoretical Models ◽  
Stellar Winds ◽  
Core Collapse ◽  
Dynamical Processes ◽  
New Approach ◽  
The Impact

AbstractWhat are the formation channels of merging black holes and neutron stars? The first two observing runs of Advanced LIGO and Virgo give us invaluable insights to address this question, but a new approach to theoretical models is required, in order to match the challenges posed by the new data. In this review, I discuss the impact of stellar winds, core-collapse and pair instability supernovae on the formation of compact remnants in both isolated and dynamically formed binaries. Finally, I show that dynamical processes, such as the runaway collision scenario and the Kozai-Lidov mechanism, leave a clear imprint on the demography of merging systems.

scholarly journals ‘A lonely old man’: empirical investigations of older men and loneliness, and the ramifications for policy and practice

2019 ◽  
pp. 1-21 ◽  
Author(s):  
John Ratcliffe ◽  
Andrea Wigfield ◽  
Sarah Alden
Keyword(s):  
Older People ◽  
Social Role ◽  
Empirical Studies ◽  
Later Life ◽  
Older Men ◽  
Implicit Assumption ◽  
Masculine Identity ◽  
Policy And Practice ◽  
The Impact ◽  
The Way

Abstract Loneliness has become an issue of significant academic, public and policy focus. There has been much research on experiences of loneliness in later life and many accompanying interventions targeting lonely older people. However, there has been a dearth of research on the impact that loneliness can have on older men and the resulting implications for policy and practice. This paper aims to redress this by developing a theoretical framework to improve understanding of older men's constructions and experiences of loneliness. It draws on two qualitative empirical studies: the first explores older men's perceptions of masculinity and loneliness; and the second looks at the effectiveness of a service for older men which was designed to alleviate loneliness among older people more generally. The paper outlines the way in which older men often construct masculinity as an oppressive (hegemonic) requirement, but which can be reformed into ‘positive’ traits of ‘strength of mind’, ‘responsibility’, ‘caring’, ‘helping out’, ‘doing a favour’ and ‘giving something back’, with a consistent yet implicit assumption that enactment of these denotes a ‘proud’ masculine identity. Loneliness, on the other hand, is represented as a subordinate social role, both non-masculine and related to marginalising stereotypes of age. This results in the identification of two important implications for the way in which services can assist in the alleviation of loneliness in older men: that men are more likely to engage with a service that can facilitate the construction of a ‘proud’ masculine identity; and that services which deconstruct hegemonic masculinities, particularly by providing a space where men feel comfortable being emotionally tactile, are likely to be most effective at both alleviating loneliness and promoting overall wellbeing.

scholarly journals Estimation of Equivalence Scale and Assessment of Its Impact on Poverty Measurement in Bangladesh

2020 ◽  
Vol 12 (21) ◽  
pp. 9081
Author(s):  
Md. Matiur Rahman ◽  
Seung-Hoon Jeon ◽  
Kyoung-Soo Yoon
Keyword(s):  
Low Income ◽  
Economies Of Scale ◽  
Household Consumption ◽  
Household Size ◽  
Poverty Measurement ◽  
Implicit Assumption ◽  
Equivalence Scale ◽  
Poverty Lines ◽  
The Impact ◽  
Scale Estimate

Anti-poverty policies for sustainable development require efficient targeting, for which appropriate poverty lines play a crucial role. In Bangladesh, official poverty lines are estimated with the implicit assumption that there are no economies of scale in household consumption with respect to household size or composition, which raises the question of the accuracy and reliability of the measurement of poverty line. We test the existence of economies of scale, estimate their size, and assess the impact of applying equivalence scale to poverty measurement, using the 2010 Household Income and Expenditure Survey data of Bangladesh. The results confirm the existence of economies of scale in household consumption. Following the model developed by Kakwani and Son, the overall index of economies of scale in household consumption is estimated around 0.85. Modified poverty lines show that under official poverty lines, the probability of being poor is high with respect to household size. The result implies that the poverty head-count ratio(HCR) for households with large number of members might be overestimated in Bangladesh, and that there may be an incentive for low income families to enlarge family size to avail of anti-poverty public transfers.

scholarly journals AGN radiative feedback in the early growth of massive black holes

2019 ◽  
Vol 489 (4) ◽  
pp. 5225-5230
Author(s):  
W Ishibashi
Keyword(s):  
Black Holes ◽  
Early Universe ◽  
Radiation Pressure ◽  
Early Growth ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
Black Hole Growth ◽  
Hole Growth ◽  
The Impact ◽  
Very High

ABSTRACT Growing observational evidence confirms the existence of massive black holes ($M_{\rm BH} \sim 10^9 \, \mathrm{M}_{\odot }$), accreting at rates close to the Eddington limit, at very high redshifts ($z \gtrsim 6\!-\!7$) in the early Universe. Recent observations indicate that the host galaxies of the first quasars are chemically evolved systems, containing unexpectedly large amounts of dust. Such a combination of high luminosities and large dust content should form favourable physical conditions for radiative dusty feedback. We explore the impact of the active galactic nucleus (AGN) feedback, driven by radiation pressure on dust, on the early growth of massive black holes. Assuming Eddington-limited exponential black hole growth, we find that the dynamics and energetics of the radiation pressure-driven outflows also follow exponential trends at late times. We obtain modest outflow energetics (with momentum flux $\dot{p} \lesssim L/c$ and kinetic power $\dot{E}_{\rm k} \lesssim 10^{-3} L$), comparable with available observations of quasar-driven outflows at very high redshifts, but significantly lower than typically observed in local quasars and predicted by wind energy-driven models. AGN radiative dusty feedback may thus play an important role in powering galactic outflows in the first quasars in the early Universe.

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