5,180 research outputs found

    The art of HIV elimination: past and present science

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    Introduction: Remarkable strides have been made in controlling the HIV epidemic, although not enough to achieve epidemic control. More recently, interest in biomedical HIV control approaches has increased, but substantial challenges with the HIV cascade of care hinder successful implementation. We summarise all available HIV prevention methods and make recommendations on how to address current challenges. Discussion: In the early days of the epidemic, behavioural approaches to control the HIV dominated, and the few available evidence-based interventions demonstrated to reduce HIV transmission were applied independently from one another. More recently, it has become clear that combination prevention strategies targeted to high transmission geographies and people at most risk of infections are required to achieve epidemic control. Biomedical strategies such as male medical circumcision and antiretroviral therapy for treatment in HIV-positive individuals and as preexposure prophylaxis in HIV-negative individuals provide immense promise for the future of HIV control. In resourcerich settings, the threat of HIV treatment optimism resulting in increased sexual risk taking has been observed and there are concerns that as ART roll-out matures in resource-poor settings and the benefits of ART become clearly visible, behavioural disinhibition may also become a challenge in those settings. Unfortunately, an efficacious vaccine, a strategy which could potentially halt the HIV epidemic, remains elusive. Conclusion: Combination HIV prevention offers a logical approach to HIV control, although what and how the available options should be combined is contextual. Therefore, knowledge of the local or national drivers of HIV infection is paramount. Problems with the HIV care continuum remain of concern, hindering progress towards the UNAIDS target of 90-90-90 by 2020. Research is needed on combination interventions that address all the steps of the cascade as the steps are not independent of each other. Until these issues are addressed, HIV elimination may remain an unattainable goal

    Green consumer markets in the fight against climate change

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    Climate change has become one of the greatest threats to environmental security, as attested by the growing frequency of severe flooding and storms, extreme temperatures and droughts. Accordingly, the European Union’s (EU) 6th Environment Action Programme (2010) lists tackling climate change as its first priority. A key aim of the EU has been to cut CO2 emissions, a major factor in climate change, by 8% until 2012 and 20% until 2020. The European Commission has proposed the encouragement of private consumer market for green products and services as one of several solutions to this problem. However, existing research suggests that the market share of these products has been only 3%, although 30% of individuals favour environmental and ethical goods. This article uses Public Goods Theory to explain why the contribution of the green consumer market to fighting climate change has been and possibly may remain limited without further public intervention

    Towards Multi-class Object Detection in Unconstrained Remote Sensing Imagery

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    Automatic multi-class object detection in remote sensing images in unconstrained scenarios is of high interest for several applications including traffic monitoring and disaster management. The huge variation in object scale, orientation, category, and complex backgrounds, as well as the different camera sensors pose great challenges for current algorithms. In this work, we propose a new method consisting of a novel joint image cascade and feature pyramid network with multi-size convolution kernels to extract multi-scale strong and weak semantic features. These features are fed into rotation-based region proposal and region of interest networks to produce object detections. Finally, rotational non-maximum suppression is applied to remove redundant detections. During training, we minimize joint horizontal and oriented bounding box loss functions, as well as a novel loss that enforces oriented boxes to be rectangular. Our method achieves 68.16% mAP on horizontal and 72.45% mAP on oriented bounding box detection tasks on the challenging DOTA dataset, outperforming all published methods by a large margin (+6% and +12% absolute improvement, respectively). Furthermore, it generalizes to two other datasets, NWPU VHR-10 and UCAS-AOD, and achieves competitive results with the baselines even when trained on DOTA. Our method can be deployed in multi-class object detection applications, regardless of the image and object scales and orientations, making it a great choice for unconstrained aerial and satellite imagery.Comment: ACCV 201

    New way to achieve chaotic synchronization in spatially extended systems

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    We study the spatio-temporal behavior of simple coupled map lattices with periodic boundary conditions. The local dynamics is governed by two maps, namely, the sine circle map and the logistic map respectively. It is found that even though the spatial behavior is irregular for the regularly coupled (nearest neighbor coupling) system, the spatially synchronized (chaotic synchronization) as well as periodic solution may be obtained by the introduction of three long range couplings at the cost of three nearest neighbor couplings.Comment: 5 pages (revtex), 7 figures (eps, included

    Modelling trade offs between public and private conservation policies

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    To reduce global biodiversity loss, there is an urgent need to determine the most efficient allocation of conservation resources. Recently, there has been a growing trend for many governments to supplement public ownership and management of reserves with incentive programs for conservation on private land. At the same time, policies to promote conservation on private land are rarely evaluated in terms of their ecological consequences. This raises important questions, such as the extent to which private land conservation can improve conservation outcomes, and how it should be mixed with more traditional public land conservation. We address these questions, using a general framework for modelling environmental policies and a case study examining the conservation of endangered native grasslands to the west of Melbourne, Australia. Specifically, we examine three policies that involve: i) spending all resources on creating public conservation areas; ii) spending all resources on an ongoing incentive program where private landholders are paid to manage vegetation on their property with 5-year contracts; and iii) splitting resources between these two approaches. The performance of each strategy is quantified with a vegetation condition change model that predicts future changes in grassland quality. Of the policies tested, no one policy was always best and policy performance depended on the objectives of those enacting the policy. This work demonstrates a general method for evaluating environmental policies and highlights the utility of a model which combines ecological and socioeconomic processes.Comment: 20 pages, 5 figure

    "Doubled" generalized Landau-Lifshiz hierarchies and special quasigraded Lie algebras

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    Using special quasigraded Lie algebras we obtain new hierarchies of integrable nonlinear vector equations admitting zero-curvature representations. Among them the most interesting is extension of the generalized Landau-Lifshitz hierarchy which we call "doubled" generalized Landau-Lifshiz hierarchy. This hierarchy can be also interpreted as an anisotropic vector generalization of "modified" Sine-Gordon hierarchy or as a very special vector generalization of so(3) anisotropic chiral field hierarchy.Comment: 16 pages, no figures, submitted to Journal of Physics

    Solvable Optimal Velocity Models and Asymptotic Trajectory

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    In the Optimal Velocity Model proposed as a new version of Car Following Model, it has been found that a congested flow is generated spontaneously from a homogeneous flow for a certain range of the traffic density. A well-established congested flow obtained in a numerical simulation shows a remarkable repetitive property such that the velocity of a vehicle evolves exactly in the same way as that of its preceding one except a time delay TT. This leads to a global pattern formation in time development of vehicles' motion, and gives rise to a closed trajectory on Δx\Delta x-vv (headway-velocity) plane connecting congested and free flow points. To obtain the closed trajectory analytically, we propose a new approach to the pattern formation, which makes it possible to reduce the coupled car following equations to a single difference-differential equation (Rondo equation). To demonstrate our approach, we employ a class of linear models which are exactly solvable. We also introduce the concept of ``asymptotic trajectory'' to determine TT and vBv_B (the backward velocity of the pattern), the global parameters associated with vehicles' collective motion in a congested flow, in terms of parameters such as the sensitivity aa, which appeared in the original coupled equations.Comment: 25 pages, 15 eps figures, LaTe

    Zeros of Rydberg-Rydberg Foster Interactions

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    Rydberg states of atoms are of great current interest for quantum manipulation of mesoscopic samples of atoms. Long-range Rydberg-Rydberg interactions can inhibit multiple excitations of atoms under the appropriate conditions. These interactions are strongest when resonant collisional processes give rise to long-range C_3/R^3 interactions. We show in this paper that even under resonant conditions C_3 often vanishes so that care is required to realize full dipole blockade in micron-sized atom samples.Comment: 10 pages, 4 figures, submitted to J. Phys.

    Response of Drought-Tolerant Hybrids to Environmental Yield Potential

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    Due to increasing non-irrigated corn acres, decreasing availability of irrigation water in some areas of western Kansas, and increasing water restrictions, producers are looking for more efficient ways to use available water. Drought-tolerant (DT) hybrid technologies are marketed for their ability to produce more stable yields in stress-prone environments. The objective of this research was to understand how DT and non-DT corn hybrids respond to a wide range of environmental conditions in terms of soil water status change, canopy indicators of stress, dry matter partitioning, and grain yield. Two DT hybrids, and one non-DT hybrid were compared in 2014 and 2015 at five locations in rain-fed, limited-irrigation, or fully irrigated regimes making a total of 18 environments. Grain yield was measured at all 18 environments, and biomass production was estimated at 14 of the environments. Yields of all hybrids were comparable in most environments, but as environment yields increased beyond 200 bu/a, one of the DT hybrids lagged behind the other two hybrids. Although one of the DT hybrids had slightly greater harvest index values than the other two hybrids in environments that resulted in a greater portion of dry matter allocated to grain, the differences were not consistent enough to be conclusive
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