1,180 research outputs found
Probably Unknown: Deep Inverse Sensor Modelling In Radar
Radar presents a promising alternative to lidar and vision in autonomous
vehicle applications, able to detect objects at long range under a variety of
weather conditions. However, distinguishing between occupied and free space
from raw radar power returns is challenging due to complex interactions between
sensor noise and occlusion.
To counter this we propose to learn an Inverse Sensor Model (ISM) converting
a raw radar scan to a grid map of occupancy probabilities using a deep neural
network. Our network is self-supervised using partial occupancy labels
generated by lidar, allowing a robot to learn about world occupancy from past
experience without human supervision. We evaluate our approach on five hours of
data recorded in a dynamic urban environment. By accounting for the scene
context of each grid cell our model is able to successfully segment the world
into occupied and free space, outperforming standard CFAR filtering approaches.
Additionally by incorporating heteroscedastic uncertainty into our model
formulation, we are able to quantify the variance in the uncertainty throughout
the sensor observation. Through this mechanism we are able to successfully
identify regions of space that are likely to be occluded.Comment: 6 full pages, 1 page of reference
Resolving fiscal imbalances: Does it take a crisis?
Many nations in the Western world face nearly unprecedented fiscal challenges, both for the medium and longer term. The Great Recession has added to fiscal pressures and public debt to nations that are already beginning to experience the fiscal fallout from aging populations. Budgeting is clouded by nearly unprecedented fiscal ambiguity, as nations are conflicted between forces demanding fiscal consolidation and those advocating growth and stimulus to jump start stagnant economies. Daunting challenges lie ahead in the next several decades for democratic nations and their leaders. With deficits and debt rising to near record levels in most nations, the recovery from the recession will still leave significant fiscal gaps that must be addressed. As nations cope with the resulting fiscal imbalances, they will also be dealing with longer-term fiscal pressures stemming from the aging of populations and rising health care costs. Unlike previous recessions, the return of strong growth will not end the fiscal gaps facing these nations, but will serve as the prelude for even more difficult and wrenching choices
Social Welfare Policy in Post-Transition Chile: Social Democratic or Neoliberal?
Chile’s massive 2019 protests indicate a pronounced discrepancy between the country’s alleged establishment of social democracy and the public’s perception of pervasive inequity. To understand this discrepancy, this analysis evaluates the extent to which Chilean social welfare policy conforms to social democratic norms of promoting solidarity, equity, and universalism. Analysis of poverty reduction, pension, health care, and education policy demonstrates that Chile’s center-left governments succeeded in mitigating some of the more extreme elements of the social welfare policies inherited from the Pinochet regime. However, they failed to reverse their underlying logic, which reinforces stratification and inequity and undermines incentives for the cultivation of solidarity among the working and middle classes. As a result, social welfare policy in Chile continues to resemble the neoliberal welfare regime implemented by the Pinochet dictatorship while the establishment of a social democratic welfare regime remains an aspiration for present and future leftist governments to realize. © The Author(s) 2023.
The available download on this page is the author manuscript accepted for publication. This version has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process
Buen Vivir under Correa: The Rhetoric of Participatory Democracy, the Reality of Rentier Populism
This article seeks to understand the relationship between populism and participatory democracy through analysis of Rafael Correa\u27s left populist regime in Ecuador (2007-2017). It argues that rather than adhering to its own standard for participatory democracy, what the Correa regime referred to as the Socialism of Buen Vivir, it employed the rhetoric of participatory democracy in the service of populist rule. As a result, the Correa regime failed to promote the participatory form of democracy and citizenship promised in Buen Vivir, its version of twenty-first-century socialism. Accordingly, analysis of the Correa regime demonstrates how the concentration of top-down executive power characteristic of populism in general, and rentier populism in particular, impedes the egalitarian and solidaristic mission of participatory democracy. Thus, inductive analysis of the Correa regime reinforces the conceptual understanding that populism is antagonistic and antithetical to participatory democracy
The Politics of Fiscal Austerity: Democracies and Foresight
Daunting fiscal policy challenges face democratic systems throughout the world. Fiscal austerity in the wake of the Great Recession prompted nations in the Organisation for Economic Co-operation and Development (OECD) to institute major spending cuts and tax increases, increases that caused political and social fallout for years to come. While economies and budgets have improved in the past several years, significant fiscal adjustments lie ahead due to aging populations and the seemingly inexorable growth of health care costs. Faced with larger cohorts of retirees and fewer workers, nations will have to come to grips with a fiscal reality of higher spending and lower revenues for the foreseeable future. This article examines whether and how fiscal austerity measures are politically stabilizing or destabilizing for elected leaders responsible for their imposition. Many would predict that democracies are ill suited to make these hard choices, and certainly regimes have gone down to defeat following the formulation of austerity programs. However, the record is mixed-many regimes have found strategies to mitigate the political fallout and guarantee reelection in the wake of austerity. While traditional incremental and pluralist politics continue to characterize the budgetary strategies of many systems, major policy reforms have risen to the center of policy agendas elsewhere. While the magnitude of the fiscal crisis prompted the adoption of major policy shifts in hard-pressed nations, such reforms were undergirded by a more volatile policy process featuring the emergence of new pathways to power with greater roles for experts and symbolically compelling ideas
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The Relationship of Hypertension in the Elderly to AD, Vascular Dementia, and Cognitive Function
Background: Hypertension at the age of 45 to 50 years may predispose to AD later in life. It is not known whether hypertension after age 65 years also contributes to AD risk, and its effect on cognitive function is also not fully understood. Methods: Data were analyzed from 1,259 Medicare recipients free of dementia in a longitudinal study covering a 7-year period (1991 to 1998). The effect of hypertension was first examined in relationship to the risk for incident AD and then to incident vascular dementia (VaD) using Cox proportional hazards models. Changes in performance over time on tasks of memory, language, and visuospatial/cognitive function were compared in those with and without hypertension using generalized estimating equations. Results: Of the 1,259 subjects, 731 (58.1%) had a history of hypertension associated with diabetes, stroke, and heart disease. A history of hypertension was not associated with an increased risk for AD (rate ratio [RR] 0.9, 95% CI 0.7 to 1.3) but was associated with an increased risk for VaD (1.8 [1.0 to 3.2]). Hypertension was not associated with changes in memory, language, and general cognitive function in normal individuals over time. Compared with individuals with neither hypertension nor heart disease, those with hypertension or heart disease alone had no increase in risk for VaD. However, when both were present, there was a threefold increase in risk for VaD. A sixfold increase in risk was observed when both hypertension and diabetes were present. Conclusions: Hypertension after age 65 years is not associated with AD and does not adversely affect memory, language, or general cognitive function. A history of hypertension may be an antecedent to VaD, particularly in the presence of heart disease or diabetes
Estudio sobre la salud mental y la calidad de vida de un grupo de cuidadores de personas con demencia y un grupo control en Cali, Colombia
Dementia caregivers are at risk for stress, depression, and a multitude of negative health outcomes, yet little research has examined the extent of these issues in caregivers from Latin America. The purpose of this study was to compare the mental health and health-related quality of life (HRQOL) of dementia caregivers to healthy controls in Cali, Colombia. Ninety dementia caregivers and 51 healthy controls completed measures of depression, satisfaction with life, stress, and HRQOL. Although it was hypothesized that dementia caregivers would report lower levels of mental health and HRQOL than controls, caregivers only reported higher depression levels. This finding suggests that dementia caregivers in this region, even when they have access to health care, are in need of mental health services and other caregiving resources. Such interventions would likely improve the mental health of caregivers and quality of care that caregivers are able to provide for individuals facing dementia.A pesar de que los cuidadores de personas con demencia están en riesgo de sufrir estrés, depresión y múltiples consecuencias negativas para la salud, se han realizado pocos estudios que hayan investigado el alcance de estos problemas en cuidadores de América Latina. El propósito de este estudio fue comparar la salud mental y la calidad de vida relacionada con la salud (CVRS) de un grupo de cuidadores de personas con demencia con un grupo de personas sanas de Cali, Colombia. Noventa cuidadores de personas con demencia y 51 personas sanas completaron una serie de cuestionarios que medía depresión, satisfacción con la vida, estrés y CVRS. A pesar de que se planteó la hipótesis de que los cuidadores de personas con demencia obtendrían niveles más bajos de salud mental y CVRS en comparación con el grupo de personas sanas, los cuidadores sólo reportaron mayores índices de depresión. Estos resultados sugieren que los cuidadores de demencia de esta región, a pesar tener acceso a los servicios de salud, necesitan servicios de salud mental y otros recursos de cuidado. Este tipo de ayudas e intervenciones probablemente ayudarían a mejorar su salud mental y la calidad de cuidado que pueden ofrecer a las personas que sufren demencia
Redetermination of μ-oxido-bis[bis(N,N-diethylhydroxylaminato)oxidovanadium(V)]
In comparison with the previous determination [Saussine, Mimoun, Mitschler & Fisher (1980 ▶). Nouv. J. Chim.
4, 235–237] of the title compound, [V2(C4H10NO)4O3], the current study reports an improved precision of the derived geometric parameters, along with the deposition of all coordinates and displacement parameters. The two VV atoms are each surrounded by two deprotonated N,O-bidentate diethylhydroxylaminate groups, and a terminal and a bridging oxide ligand, in a distorted octahedral coordination geometry. The crystal packing is accomplished by van der Waals interactions
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Modeling multivalent ligand-receptor interactions with steric constraints on configurations of cell surface receptor aggregates
Signal transduction generally involves multivalent protein-protein interactions, which can produce various protein complexes and post-translational modifications. The reaction networks that characterize these interactions tend to be so large as to challenge conventional simulation procedures. To address this challenge, a kinetic Monte Carlo (KMC) method has been developed that can take advantage of a model specification in terms of reaction rules for molecular interactions. A set of rules implicitly defines the reactions that can occur as a result of the interactions represented by the rules. With the rule-based KMC method, explicit generation of the underlying chemical reaction network implied by rules is avoided. Here, we apply and extend this method to characterize the interactions of a trivalent ligand with a bivalent cell-surface receptor. This system is also studied experimentally. We consider the following kinetic models: an equivalent-site model, an extension of this model, which takes into account steric constraints on the configurations of receptor aggregates, and finally, a model that accounts for cyclic receptor aggregates. Simulation results for the equivalent-site model are consistent with an equilibrium continuum model. Using these models, we investigate the effects of steric constraints and the formation of cyclic aggregates on the kinetics and equilibria of small and large aggregate formation and the percolation phase transition that occurs in this system
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