162 research outputs found
Dissipative inertial transport patterns near coherent Lagrangian eddies in the ocean
Recent developments in dynamical systems theory have revealed long-lived and
coherent Lagrangian (i.e., material) eddies in incompressible,
satellite-derived surface ocean velocity fields. Paradoxically, observed
drifting buoys and floating matter tend to create dissipative-looking patterns
near oceanic eddies, which appear to be inconsistent with the conservative
fluid particle patterns created by coherent Lagrangian eddies. Here we show
that inclusion of inertial effects (i.e., those produced by the buoyancy and
size finiteness of an object) in a rotating two-dimensional incompressible flow
context resolves this paradox. Specifically, we obtain that anticyclonic
coherent Lagrangian eddies attract (repel) negatively (positively) buoyant
finite-size particles, while cyclonic coherent Lagrangian eddies attract
(repel) positively (negatively) buoyant finite-size particles. We show how
these results explain dissipative-looking satellite-tracked surface drifter and
subsurface float trajectories, as well as satellite-derived \emph{Sargassum}
distributions.Comment: Submitted to \emph{Chaos} Focus Issue on Objective detection of
Lagrangian Coherent Structures. Revised 23-Feb-1
Electoral and political changes: the impact on political bureaucratic relationships in Scottish Local Government
PublicâPrivate Partnership in Tunisia: Enfidha Airport Assessment of an Infrastructure Achievement
One of the largest recent private-sector investments and the first airport private-sector concession
in the Maghreb is Enfidha Airport, a key factor in the success of the Tunisian Governmentâs publicâ
private partnership (PPP) strategy. However, since Tunisiaâs Jasmine Revolution, political and social
turmoil is sweeping the country and worsening the economic indicators. This article aims to assess
this PPP infrastructure, allowing us to determine if it is profitable in the long term and contributes
therefore to the economic growth. The case study reveals the key role of the economic, social, and
political environment in Tunisia, the dawn of the Arab Spring
Relative periodic orbits form the backbone of turbulent pipe flow
The chaotic dynamics of low-dimensional systems, such as Lorenz or Rössler flows, is guided by the infinity of periodic orbits embedded in their strange attractors. Whether this is also the case for the infinite-dimensional dynamics of NavierâStokes equations has long been speculated, and is a topic of ongoing study. Periodic and relative periodic solutions have been shown to be involved in transitions to turbulence. Their relevance to turbulent dynamics â specifically, whether periodic orbits play the same role in high-dimensional nonlinear systems like the NavierâStokes equations as they do in lower-dimensional systems â is the focus of the present investigation. We perform here a detailed study of pipe flow relative periodic orbits with energies and mean dissipations close to turbulent values. We outline several approaches to reduction of the translational symmetry of the system. We study pipe flow in a minimal computational cell at , and report a library of invariant solutions found with the aid of the method of slices. Detailed study of the unstable manifolds of a sample of these solutions is consistent with the picture that relative periodic orbits are embedded in the chaotic saddle and that they guide the turbulent dynamics
Partnership and Capacity Building of Local Governance
Partnership is about sharing of power, responsibility and achievements. According to the World Bank Public Private Partnership (PPP) promoting group, âpartnership refer to informal and shortterm engagements of non-governmental organizations, the private sector and/or government agencies that join forces for a shared objective; to more formal, but still short-term private sector engagements for the provision of specific services, for example, annual outsourcing arrangements for janitorial services for a school or operations of the school cafeteria; to more complex contractual arrangements, such as build, operate, transfer regimes, where the private sector takes on considerable risk and remains engaged long term; or to full privatizationsâ (World Bank Group 2014, 29).© Springer Nature Switzerland AG 2020. This is a post-peer-review, pre-copyedit version of an article published in Partnerships for the Goals. Encyclopedia of the UN Sustainable Development Goals. The final authenticated version is available online at: http://dx.doi.org/10.1007/978-3-319-71067-9_21-1.fi=vertaisarvioitu|en=peerReviewed
A Cross-Sectional Study on Attitudes to and Understanding of Risk of Acquisition of HIV: Design, Methods and Participant Characteristics
Background: The annual number of new human immunodeficiency virus (HIV) infections in the United Kingdom among men who have sex with men (MSM) has risen, and remains high among heterosexuals. Increasing HIV transmission among MSM is consistent with evidence of ongoing sexual risk behavior in this group, and targeted prevention strategies are needed for those at risk of acquiring HIV.
Objective: The Attitudes to and Understanding of Risk of Acquisition of HIV (AURAH) study was designed to collect information on HIV negative adults at risk of HIV infection in the United Kingdom, based on the following parameters: physical and mental health, lifestyle, patterns of sexual behaviour, and attitudes to sexual risk.
Methods: Cross-sectional questionnaire study of HIV negative or undiagnosed sexual health clinic attendees in the United Kingdom from 2013-2014.
Results: Of 2630 participants in the AURAH study, 2064 (78%) were in the key subgroups of interest; 580 were black Africans (325 females and 255 males) and 1484 were MSM, with 27 participants belonging to both categories.
Conclusions: The results from AURAH will be a significant resource to understand the attitudes and sexual behaviour of those at risk of acquiring HIV within the United Kingdom. AURAH will inform future prevention efforts and targeted health promotion initiatives in the HIV negative population
Editorsâ Introduction: An Overview of the Educational Administration and Leadership Curriculum: Traditions of Islamic Educational Administration and Leadership in Higher Education
This chapter provides an overview of several topics relevant to constructing an approach to teaching educational administration and leadership in Muslim countries. First, it places the topic in the context of the changing nature and critiques of the field that argue for a greater internationalisation to both resist some of the negative aspects of globalisation and to represent countriesâ traditions in the professional curriculum. Then, it identifies literature that presents the underlying principles and values of Islamic education that guide curriculum and pedagogy and shape its administration and leadership including the Qurâan and Sunnah and the classical educational literature which focuses on aims, values and goals of education as well as character development upon which a âgoodâ society is built. This is followed by a section on the Islamic administration and leadership traditions that are relevant to education, including the values of educational organisations and how they should be administered, identifying literature on the distinctive Islamic traditions of leadership and administrator education and training as it applies to education from the establishment of Islam and early classical scholars and senior administrators in the medieval period who laid a strong foundation for a highly sophisticated preparation and practice of administration in philosophical writings and the Mirrors of Princes writings, and subsequent authors who have built upon it up to the contemporary period. The final section provides an overview of the chapters in this collection
Improving the evidence for indicator condition guided HIV testing in Europe: Results from the HIDES II Study - 2012 - 2015
BACKGROUND: It is cost-effective to perform an HIV test in people with specific indicator conditions (IC) with an undiagnosed HIV prevalence of at least 0.1%. Our aim was to determine the HIV prevalence for 14 different conditions across 20 European countries. METHODS: Individuals aged 18-65 years presenting for care with one of 14 ICs between January 2012 and June 2014 were included and routinely offered an HIV test. Logistic regression assessed factors associated with testing HIV positive. Patients presenting with infectious mononucleosis-like syndrome (IMS) were recruited up until September 2015. RESULTS: Of 10,877 patients presenting with an IC and included in the analysis, 303 tested positive (2.8%; 95% CI 2.5-3.1%). People presenting with an IC in Southern and Eastern Europe were more likely to test HIV positive as were people presenting with IMS, lymphadenopathy and leukocytopenia/ thrombocytopenia. One third of people diagnosed with HIV after presenting with IMS reported a negative HIV test in the preceding 12 months. Of patients newly diagnosed with HIV where data was available, 92.6% were promptly linked to care; of these 10.4% were reported lost to follow up or dead 12 months after diagnosis. CONCLUSION: The study showed that 10 conditions had HIV prevalences > 0.1%. These 10 ICs should be adopted into HIV testing and IC specialty guidelines. As IMS presentation can mimic acute HIV sero-conversion and has the highest positivity rate, this IC in particular affords opportunities for earlier diagnosis and public health benefit
Local Sensemaking of Policy Paradoxes â Implementing Local Crime Prevention in Sweden
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