Suppose C is a cone contained in real vector space V. When does V contain a hyperplane H that intersects each of the 0-rays in C∖{0} exactly once? We build on results found in Aliprantis, Tourky, and ...Klee Jr.’s work to give a partial answer to this question. We also present an example of a salient, closed Banach space cone C for which there does not exist a hyperplane that intersects each 0-ray in C∖{0} exactly once.
Since the 1960s researchers have developed a range of techniques for evaluating landscape preference. In parallel with this trend, eye-tracking technology has become cheaper, more mobile and more ...accurate, heralding a new era of big data capture and analysis for landscape preference. In this project our objective was to capitalise on the increasing mobility, sophistication and cheapness of eye-tracking technology to examine its utility in analysing landscape preference. In the following we describe how we eye-tracked 35 participants as they viewed walks through two different parks in the urban center of Melbourne, Australia. We show how participants dwelt on trees and bushes more than other objects. When we compared this to the time and space that objects occupy, participants overwhelmingly dwelt on artificial objects such as lamp-posts, distant buildings and benches. Overall we provide an exploration and method for analysing eye-tracking data in parks by normalising the dwell time by the content, providing a robust means of comparing different dynamic stimuli such as videos.
China’s Belt and Road Initiative (BRI) needs little introduction; the infrastructure investment will reconfigure development in Central Asia. As its origin story and initial encounter, Central Asia ...offers a prismatic lens to delve into the vital impacts and significant changes wrought by the BRI. In the dryland region, the BRI impact on watersheds and agriculture is a critical challenge with direct implications for food security. Framed by diverse research sources, we utilized spatial datasets from the European Space Agency Climate Change Initiative and the World Bank to explore the intersection of food production, water and development. Investigation evaluates the possible trade-offs that Chinese infrastructure investment can have on the communities and environment of Central Asia. The findings identify more than 15,000 km of rail and 20,000 km of roads linked to the BRI crisscrossing the region in 2018. Whilst these transport corridors have improved connectivity, many of these rails and roads traverse important agricultural and water zones, creating undetermined risks and opportunities. Land use change was examined within a 10-km buffer around BRI roads and rails from 2008 to 2018. Railways increased by 23% during this time, yet irrigated and rainfed agriculture decreased whilst urban areas markedly expanded. Contextual research identifies how Chinese policies may encourage agribusiness investment for food exports as possible disruptions to national and regional food supply. However, to date Central Asia provides <1% of Chinese agricultural imports. In fact, Afghanistan is the region’s dominant export market, tripling agricultural imports >300% in this time. Similarly, five times more livestock are traded within the region than to China. Evaluating infrastructure change is essential to understand BRI impacts on environments and societies, with the food-water nexus a particular concern in Central Asia. Limited Chinese imports of Central Asian agriculture suggests the region’s food security will not be significantly altered by the Belt and Road Initiative.
Amidst escalating global environmental challenges, does environmental aid drive tangible conservation outcomes in developing countries or does it merely perpetuate the rift between economic ambition ...and environmental responsibility? Using a comprehensive ten-year dataset from the OECD, World Bank, Climate Watch, and the Climate Change Laws of the World database, we analyze the relationship between environmental aid and environmental conservation outcomes in recipient countries. Our results indicate that although aid can influence policy development, there is a weak correlation with outcomes such as increased forest cover, expansion of protected areas, and reduced CO2 emissions. Moreover, the pronounced roles of GDP and population in shaping these outcomes underline the complex interplay of environmental challenges with economic growth and demographic shifts. This dynamic, coupled with the evident mismatch between environmental aid delivery and tangible conservation improvements, emphasizes the need to reconsider current aid distribution strategies. In light of current environmental challenges, this research offers valuable insights into the effectiveness of environmental aid in developing countries and suggests a way forward for more targeted and impactful conservation efforts.
Abstract
Thousands of exoplanet detections have been made over the last 25 years using Doppler observations, transit photometry, direct imaging, and astrometry. Each of these methods is sensitive to ...different ranges of orbital separations and planetary radii (or masses). This makes it difficult to fully characterize exoplanet architectures and to place our solar system in context with the wealth of discoveries that have been made. Here, we use the EXtreme PREcision Spectrograph to reveal planets in previously undetectable regions of the mass–period parameter space for the star
ρ
Coronae Borealis. We add two new planets to the previously known system with one hot Jupiter in a 39 day orbit and a warm super-Neptune in a 102 day orbit. The new detections include a temperate Neptune planet (
M
sin
i
∼
20
M
⊕
) in a 281.4 day orbit and a hot super-Earth (
M
sin
i
=
3.7
M
⊕
) in a 12.95 day orbit. This result shows that details of planetary system architectures have been hiding just below our previous detection limits; this signals an exciting era for the next generation of extreme precision spectrographs.
Over the past decade, there has been increasing interest in advanced secondary mobility aids for people with low vision, such as sensory substitution devices (SSDs) and electronic travelling aids ...(ETAs). However, these new modalities have not been able to reach end-users in significant numbers. We conducted an online survey to investigate the current uptake of mobility aids, as well as perspectives on emerging technologies from people with inherited retinal disease (IRD). The cross-sectional survey received 74 complete responses from Australians that self-reported as legally blind from IRD. Approximately half (57%) of respondents were aged over 55 years, with the cohort exhibiting above average education levels (with half holding a bachelor’s degree or above). Long canes (54%) are currently the most used primary mobility aids in this cohort. However, around half of the respondents have used ETAs or SSDs (51 %) for additional help. Respondents reported that their choice of mobility aid was often based on whether they were in a familiar or unfamiliar environment. Most respondents showed interest in SSDs, but were concerned about usability and aesthetics. This cohort of people living with IRD in Australia was interested in advanced technologies and showed willingness to try novel mobility aids if the device was easy to use and the quality of training was guaranteed. Respondents indicated a preference for devices which were portable, and had a minimally intrusive form-factor. Our results can inform the research and development of emerging assistive devices. They serve as valuable guidance for selecting aids tailored to the needs of individuals with visual impairments. Future assessments on the effectiveness of low vision aids should include not only the functional improvement, but also participant-reported assessments regarding usability and portability, as these aspects dictate integration of the device into regular use.
We evaluated a novel visual representation for current and near-term prosthetic vision. Augmented depth emphasizes ground obstacles and floor-wall boundaries in a depth-based visual representation. ...This is achieved by artificially increasing contrast between obstacles and the ground surface via a novel ground plane extraction algorithm specifically designed to preserve low-contrast ground-surface boundaries.
The effectiveness of augmented depth was examined in human mobility trials compared against standard intensity-based (Intensity), depth-based (Depth) and random (Random) visual representations. Eight participants with normal vision used simulated prosthetic vision with 20 phosphenes and eight perceivable brightness levels to traverse a course with randomly placed small and low-contrast obstacles on the ground.
The number of collisions was significantly reduced using augmented depth, compared with intensity, depth and random representations (48%, 44% and 72% less collisions, respectively).
These results indicate that augmented depth may enable safe mobility in the presence of low-contrast obstacles with current and near-term implants. This is the first demonstration that an augmentation of the scene ensuring key objects are visible may provide better outcomes for prosthetic vision.
This study designed, developed, and evaluated a deep-learning-based companion robot prototype for indoor navigation and obstacle avoidance using an RGB-D camera as the sole input sensor. This study ...proposed a dynamic path planning (DPP) method that combines instance image segmentation and elementary matrix calculations to enable a robot to identify the angular position of entities in its surroundings. The DPP method fuses visual and depth information for scene understanding and path estimation with reduced computation resources. A simulated environment assessed the robot's path-planning ability through computer vision. The DPP method enables the person-following robot to perform intelligent curve manipulation for safe path planning to avoid objects in the initial trajectory. The approach offers a unique and straightforward technique for scene understanding without the burden of extensive neural network configuration. Its modular architecture and flexibility make it a promising candidate for future development and refinement in this domain. Its effectiveness in collision prevention and path planning has potential implications for various applications, including medical robotics.
With a retinal prosthesis connected to a head-mounted camera, subjects can perform low vision tasks using a combination of electrode discrimination and head-directed localization. The objective of ...the present study was to investigate the contribution of retinotopic electrode discrimination (perception corresponding to the arrangement of the implanted electrodes with respect to their position beneath the retina) to visual performance for three recipients of a 24-channel suprachoroidal retinal implant. Proficiency in retinotopic discrimination may allow good performance with smaller head movements, and identification of this ability would be useful for targeted rehabilitation.
Three participants with retinitis pigmentosa performed localization and grating acuity assessments using a suprachoroidal retinal prosthesis. We compared retinotopic and nonretinotopic electrode mapping and hypothesized that participants with measurable acuity in a normal retinotopic condition would be negatively impacted by the nonretinotopic condition. We also expected that participants without measurable acuity would preferentially use head movement over retinotopic information.
Only one participant was able to complete the grating acuity task. In the localization task, this participant exhibited significantly greater head movements and significantly lower localization scores when using the nonretinotopic electrode mapping. There was no significant difference in localization performance or head movement for the remaining two subjects when comparing retinotopic to nonretinotopic electrode mapping.
Successful discrimination of retinotopic information is possible with a suprachoroidal retinal prosthesis. Head movement behavior during a localization task can be modified using a nonretinotopic mapping. Behavioral comparisons using retinotopic and nonretinotopic electrode mapping may be able to highlight deficiencies in retinotopic discrimination, with a view to address these deficiencies in a rehabilitation environment. (ClinicalTrials.gov number, NCT01603576).
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