13,079 research outputs found
Don't break a leg: Running birds from quail to ostrich prioritise leg safety and economy in uneven terrain
Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force–length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force–length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics
Studying Migrant Assimilation Through Facebook Interests
Migrants' assimilation is a major challenge for European societies, in part
because of the sudden surge of refugees in recent years and in part because of
long-term demographic trends. In this paper, we use Facebook's data for
advertisers to study the levels of assimilation of Arabic-speaking migrants in
Germany, as seen through the interests they express online. Our results
indicate a gradient of assimilation along demographic lines, language spoken
and country of origin. Given the difficulty to collect timely migration data,
in particular for traits related to cultural assimilation, the methods that we
develop and the results that we provide open new lines of research that
computational social scientists are well-positioned to address.Comment: Accepted as a short paper at Social Informatics 2018
(https://socinfo2018.hse.ru/). Please cite the SocInfo versio
CW high intensity non-scaling FFAG proton drivers
Accelerators are playing increasingly important roles in basic science,
technology, and medicine including nuclear power, industrial irradiation,
material science, and neutrino production. Proton and light-ion accelerators in
particular have many research, energy and medical applications, providing one
of the most effective treatments for many types of cancer. Ultra high-intensity
and high-energy (GeV) proton drivers are a critical technology for
accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon
Collider). These high-intensity GeV-range proton drivers are particularly
challenging, encountering duty cycle and space-charge limits in the synchrotron
and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton
driver is not presently considered technically achievable with conventional
re-circulating accelerators. One, as-yet, unexplored re-circulating
accelerator, the Fixed-field Alternating Gradient, or FFAG, is an attractive
alternative to the cyclotron. Its strong focusing optics are expected to
mitigate space charge effects, and a recent innovation in design has coupled
stable tunes with isochronous orbits, making the FFAG capable of
fixed-frequency, CW acceleration, as in the classical cyclotron. This paper
reports on these new advances in FFAG accelerator technology and references
advanced modeling tools for fixed-field accelerators developed for and unique
to the code COSY INFINITY.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1
Apr 2011. New York, US
Improving health and well-being through community health champions: a thematic evaluation of a programme in Yorkshire and Humber.
AIMS: The contribution that lay people can make to the public health agenda is being increasingly recognised in research and policy literature. This paper examines the role of lay workers (referred to as 'community health champions') involved in community projects delivered by Altogether Better across Yorkshire and Humber. The aim of the paper is to describe key features of the community health champion approach and to examine the evidence that this type of intervention can have an impact on health. METHODS: A qualitative approach was taken to the evaluation, with two strands to gathering evidence: interviews conducted with different stakeholder groups including project leads, key partners from community and statutory sectors and community workers, plus two participatory workshops to gather the views of community health champions. Seven projects (from a possible 12) were identified to be involved in the evaluation. Those projects that allowed the evaluation team to explore fully the champion role (training, infrastructure, etc.) and how that works in practice as a mechanism for empowerment were selected. In total, 29 semi-structured interviews were conducted with project staff and partners, and 30 champions, varying in terms of age, gender, ethnicity and disability, took part in the workshops. RESULTS: Becoming a community health champion has health benefits such as increased self-esteem and confidence and improved well-being. For some champions, this was the start of a journey to other opportunities such as education or paid employment. There were many examples of the influence of champions extending to the wider community of family, friends and neighbours, including helping to support people to take part in community life. Champions recognised the value of connecting people through social networks, group activities, and linking people into services and the impact that that had on health and well-being. Project staff and partners also recognised that champions were promoting social cohesiveness and helping to integrate people into their community. CONCLUSIONS: The recent public health White Paper suggested that the Altogether Better programme is improving individual and community health as well as increasing social capital, voluntary activity and wider civic participation. This evaluation supports this statement and suggests that the community health champion role can be a catalyst for change for both individuals and communities
The one-loop six-dimensional hexagon integral with three massive corners
We compute the six-dimensional hexagon integral with three non-adjacent
external masses analytically. After a simple rescaling, it is given by a
function of six dual conformally invariant cross-ratios. The result can be
expressed as a sum of 24 terms involving only one basic function, which is a
simple linear combination of logarithms, dilogarithms, and trilogarithms of
uniform degree three transcendentality. Our method uses differential equations
to determine the symbol of the function, and an algorithm to reconstruct the
latter from its symbol. It is known that six-dimensional hexagon integrals are
closely related to scattering amplitudes in N=4 super Yang-Mills theory, and we
therefore expect our result to be helpful for understanding the structure of
scattering amplitudes in this theory, in particular at two loops.Comment: 15 pages, 2 figure
The capabilities approach and critical social policy: lessons from the majority world?
The capabilities approach (CA) most closely associated with the thinner and thicker versions of Sen and Nussbaum has the potential to provide a paradigm shift for critical social policy, encompassing but also transcending some of the limitations associated with the Marshallian social citizenship approach. The article argues, however, that it cannot simply be imported from the majority world, rather there is a need to bear in mind the critical literature that developed around it. This is generally discussed and then critically applied to case studies of CA in the developed capitalist world, particularly the Equalities Review conducted for the Equality and Human Rights Commission
Knowledge Transfer and Teaching Public Administration: the Academy Model
Since the beginnings of Public Administration in the US and its accompanying education in other parts of the world, government and policy have become more complex. The education in Public Administration created a professional pathway to public service. The addition of education to Public Administration came out of the Progressive Movement in the United States to make knowledge in Public Administration more important in the face of corruption brought on by patronage appointments. When nonprofits became part the US public sector as elsewhere along with nonprofit healthcare, the complexity expanded enormously, requiring professionals to know more in what has become a multidisciplinary field of study. Given the diversity and complexity of the public sector and the need for Public Administration to embrace more knowledge from many disciplines, it stands to reason that an earlier start on the education portion of Public Administration or a pathway would be beneficial. A model of early Public Administration knowledge transfer is described and illustrated below. The Academy described is based on the US career pathways and high school academies as part of the school to work educational movement. The success of the combination of these two areas will also be pointed out in the academy described. Translation of lessons learned from the Acdemy to Europe and Asia are also considered
A Global Hypothesis for Women in Journalism and Mass Communications: The Ratio of Recurrent and Reinforced Residuum
This paper examines the status of women in communications industries and on university faculties. It specifically tests the Ratio of Recurrent and Reinforced Residuum or R3 hypothesis, as developed by Rush in the early 1980s [Rush, Buck & Ogan,1982]. The R3 hypothesis predicts that the percentage of women in the communications industries and on university faculties will follow the ratio residing around 1/4:3/4 or 1/3:2/3 proportion females to males. This paper presents data from a nationwide U.S. survey and compares them to data from global surveys and United Nations reports. The evidence is overwhelming and shows the relevance and validity of the R3 hypothesis across different socio-economic and cultural contexts. The paper argues that the ratio is the outcome of systemic discrimination that operates at multiple levels. The obstacles to achieving equality in the academy as well as media industries are discussed and suggestions for breaking out of the R3 ratio are included.
A Global Hypothesis for Women in Journalism and Mass Communications: The Ratio of Recurrent and Reinforced Residuum
This paper examines the status of women in communications industries and on university faculties. It specifically tests the Ratio of Recurrent and Reinforced Residuum or R3 hypothesis, as developed by Rush in the early 1980s [Rush, Buck & Ogan,1982]. The R3 hypothesis predicts that the percentage of women in the communications industries and on university faculties will follow the ratio residing around 1/4:3/4 or 1/3:2/3 proportion females to males. This paper presents data from a nationwide U.S. survey and compares them to data from global surveys and United Nations reports. The evidence is overwhelming and shows the relevance and validity of the R3 hypothesis across different socio-economic and cultural contexts. The paper argues that the ratio is the outcome of systemic discrimination that operates at multiple levels. The obstacles to achieving equality in the academy as well as media industries are discussed and suggestions for breaking out of the R3 ratio are included.
WTO accession, the changing competitiveness of foreign-financed firms and regional development in Guangdong of southern China
This paper investigates the changing competitiveness of foreign-financed manufacturing firms and its implications for regional development in Guangdong province of southern China in the run-up to World Trade Organization (WTO) accession. It is argued that transnational corporations (TNCs) and some competitive, large-scale, locally-funded firms in Guangdong will triumph after WTO accession. The crowding-out process of small and medium sized enterprises (SMEs) in Guangdong will be accelerated in the near future, as they are competing directly with TNCs, and as their competitive advantages are diminishing, due to bureaucratic red tape and the rigorous enforcement of new government policies. Due to close business linkages with local privately-funded firms, the competitiveness and vitality of foreign-financed enterprises will have profound long term effects on the economic development of Guangdong, before and after WTO accession
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