87 research outputs found
Trifocal Relative Pose from Lines at Points and its Efficient Solution
We present a new minimal problem for relative pose estimation mixing point
features with lines incident at points observed in three views and its
efficient homotopy continuation solver. We demonstrate the generality of the
approach by analyzing and solving an additional problem with mixed point and
line correspondences in three views. The minimal problems include
correspondences of (i) three points and one line and (ii) three points and two
lines through two of the points which is reported and analyzed here for the
first time. These are difficult to solve, as they have 216 and - as shown here
- 312 solutions, but cover important practical situations when line and point
features appear together, e.g., in urban scenes or when observing curves. We
demonstrate that even such difficult problems can be solved robustly using a
suitable homotopy continuation technique and we provide an implementation
optimized for minimal problems that can be integrated into engineering
applications. Our simulated and real experiments demonstrate our solvers in the
camera geometry computation task in structure from motion. We show that new
solvers allow for reconstructing challenging scenes where the standard two-view
initialization of structure from motion fails.Comment: This material is based upon work supported by the National Science
Foundation under Grant No. DMS-1439786 while most authors were in residence
at Brown University's Institute for Computational and Experimental Research
in Mathematics -- ICERM, in Providence, R
Political Effects on the Discontinuation of Participatory Budgeting in Municipalities
The article analyzes the factors associated with the discontinuation of participatory budgeting (PB) in Brazilian municipalities with more than 50,000 inhabitants between 2000 and 2016. We used econometric models to estimate PB’s discontinuation based on political explanatory variables and people’s local participation. The results indicate that discontinuation is associated: (i) positively with the election of a different local government, regardless of the winning party’s ideology; (ii) positively with the election of a local government with a left-wing ideology’; (iii) negatively with the election of a non-left-wing local government; (iv) positively with the election of a left-wing local government replacing another left-wing government. Changes in local government where other non-left-wing parties replace non-left-wing parties had no significant effect on discontinuation. The results contribute to our knowledge by showing the local and contextual factors that explain the discontinuation of participatory budgeting; this should help guide the design of participatory public policies and allow practitioners to reflect on the mechanisms that could be adopted locally to avoid discontinuation. The article also contributes to the literature by demonstrating the association between discontinuation and changes in left-wing local governments, which may prompt future research, given the unexpected result
The impact of Participatory Budgeting on health and wellbeing:A scoping review of evaluations
Background: Participatory budgeting (PB), citizens deliberating among themselves and with officials to decide how
to allocate funds for public goods, has been increasingly implemented across Europe and worldwide. While PB is
recommended as good practice by the World Bank and the United Nations, with potential to improve health and
wellbeing, it is unclear what evaluations have been conducted on the impact of PB on health and wellbeing.
Methods: For this scoping review, we searched 21 databases with no restrictions on publication date or language.
The search term ‘participatory budget’ was used as the relevant global label for the intervention of interest. Studies
were included if they reported original analysis of health, social, political, or economic and budgetary outcomes of
PB. We examined the study design, analysis, outcomes and location of included articles. Findings are reported
narratively.
Results: From 1458 identified references, 37 studies were included. The majority of evaluations (n = 24) were of PB
in South America, seven were in Europe. Most evaluations were case studies (n = 23) conducting ethnography and
surveys, focussing on political outcomes such as participation in PB or impacts on political activities. All of the
quantitative observational studies analysing population level data, except one in Russia, were conducted in South
America.
Conclusion: Despite increasing interest in PB, evaluations applying robust methods to analyse health and
wellbeing outcomes are scarce, particularly beyond Brazil. Therefore, implementation of PB schemes should be
accompanied by rigorous qualitative and quantitative evaluation to identify impacts and the processes by which
they are realised
The infrared properties of active extragalactic nuclei
In this paper we review the observed infrared properties of the general classes of active extragalactic nuclei with the purpose of relating the observations to the mechanisms responsible for the emission processes. We will first give a summary of those observations which define the energy distributions and emission line ratios of broad groups of objects. We will intersperse measurements of specific features throughout the discussion that illustrate definite emission mechanisms
Supernova remnants: the X-ray perspective
Supernova remnants are beautiful astronomical objects that are also of high
scientific interest, because they provide insights into supernova explosion
mechanisms, and because they are the likely sources of Galactic cosmic rays.
X-ray observations are an important means to study these objects.And in
particular the advances made in X-ray imaging spectroscopy over the last two
decades has greatly increased our knowledge about supernova remnants. It has
made it possible to map the products of fresh nucleosynthesis, and resulted in
the identification of regions near shock fronts that emit X-ray synchrotron
radiation.
In this text all the relevant aspects of X-ray emission from supernova
remnants are reviewed and put into the context of supernova explosion
properties and the physics and evolution of supernova remnants. The first half
of this review has a more tutorial style and discusses the basics of supernova
remnant physics and thermal and non-thermal X-ray emission. The second half
offers a review of the recent advances.The topics addressed there are core
collapse and thermonuclear supernova remnants, SN 1987A, mature supernova
remnants, mixed-morphology remnants, including a discussion of the recent
finding of overionization in some of them, and finally X-ray synchrotron
radiation and its consequences for particle acceleration and magnetic fields.Comment: Published in Astronomy and Astrophysics Reviews. This version has 2
column-layout. 78 pages, 42 figures. This replaced version has some minor
language edits and several references have been correcte
Representatividade e inovação na governança dos processos participativos: o caso das organizações Brasileiras de agricultores familiares
Português
Este artigo discute o orçamento participativo por uma ótica pouco explorada pela literatura: a dimensão do orçamento. A literatura que trata o orçamento participativo em geral foca no lado da participação, buscando analisar quais são os seus determinantes, barreiras para a adoção, e efeitos causados pela participação. O objetivo do artigo é trazer reflexões sobre a participação no ciclo orçamentário, analisando possíveis formas de participação em cada etapa, em que se busca trazer reflexões tanto para pesquisas quanto para os adotantes de mecanismos de orçamento participativo. Adicionalmente, indicamos caminhos ainda pouco explorados pela literatura sobre orçamento participativo
No Benefit in Neurologic Outcomes of Survivors of Out-of-Hospital Cardiac Arrest with Mechanical Compression Device
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