Midperipheral mini-capsulorhexis as an additional step for safe phacoemulsification in white intumescent cataracts.

ABSTRACT: The present article describes a novel surgical technique of a primary mini-capsulorhexis in midperiphery to minimize surgical complications in white intumescent cataracts. Patients with white mature cataracts with a convex anterior capsule or swollen lens fibers were selected. An initial puncture was made 3-4 mm away from the center, in the midperipheral anterior capsule, with a conventional cystitome. A mini-capsulorhexis (2-2.5 mm) was created. Loose cortical matter and fluidic contents were aspirated to reduce the intralenticular pressure. Two cuts were made at the margin of the mini-capsulorhexis, and an adequately sized secondary rhexis was completed, after which phacoemulsification was done. A circular curvilinear capsulorhexis was successfully achieved in all cases, including those with a small pupil. Rhexis could be completed in a patient where an initial extension occurred due to head movement. This refined technique aims to enhance the safety and precision of capsulorhexis in intumescent cataracts, thereby reducing the risk of complications such as the Argentinian flag sign. Further exploration and validation of this approach through clinical trials are warranted to establish its efficacy and safety profile.

Landscape-scale hydrologic response of plant invasion relative to native vegetation in urban forests.

Large-scale invasion modifies watershed hydrology by changing surface runoff and lowering the seasonal availability of water to native plants. Due to costly field-based evapotranspiration (ET) measurements, which are highly localized and occasionally subject to instrument failure, landscape-scale water use assessments of invasive plants are infrequent. Therefore, the extent to which plant invaders alter water allocation between native and non-native vegetation in a given landscape is rarely assessed. We used a remote sensing-based ET modeling approach to measure the hydrologic response of an invasive shrub, Ligustrum sinense, across forests of the Charlotte Metropolitan Area, North Carolina. We hypothesized that this invader's widespread occurrence and dominant plant physiology significantly competes with native forests for water resources. We tested this hypothesis by comparing inter- and intra-annual variations in ET from invaded and uninvaded sites estimated using the surface-energy-balance system (SEBS) model and cloud-free Landsat images for the wettest (2003), driest (2007), and normal (2005 and 2011) water years. Our findings suggest that the water demand of L. sinense is higher than native forests (deciduous and evergreen) for most of the year except during the early spring and after high precipitation events. The daily ET flux of L. sinense was significantly different than evergreen vegetation during the driest year (2007) that, five years later (2011 - normal water year), was significantly different than both deciduous and evergreen vegetation types. This suggests that L. sinense consumes more water than native forest types, particularly during dry and normal precipitation years with increasing canopy cover over time making it a strong competitor with native vegetation for water resources in urban forests. Therefore, accounting for the hydrologic response of invasive plants and potential water savings from their removal from forests, particularly in water-scarce regions, may enable land managers and decision-makers to prioritize areas for monitoring and control efforts.

The managed clearing: An overlooked land-cover type in urbanizing regions?

Urban ecosystem assessments increasingly rely on widely available map products, such as the U.S. Geological Service (USGS) National Land Cover Database (NLCD), and datasets that use generic classification schemes to detect and model large-scale impacts of land-cover change. However, utilizing existing map products or schemes without identifying relevant urban class types such as semi-natural, yet managed land areas that account for differences in ecological functions due to their pervious surfaces may severely constrain assessments. To address this gap, we introduce the managed clearings land-cover type-semi-natural, vegetated land surfaces with varying degrees of management practices-for urbanizing landscapes. We explore the extent to which managed clearings are common and spatially distributed in three rapidly urbanizing areas of the Charlanta megaregion, USA. We visually interpreted and mapped fine-scale land cover with special attention to managed clearings using 2012 U.S. Department of Agriculture (USDA) National Agriculture Imagery Program (NAIP) images within 150 randomly selected 1-km2 blocks in the cities of Atlanta, Charlotte, and Raleigh, and compared our maps with National Land Cover Database (NLCD) data. We estimated the abundance of managed clearings relative to other land use and land cover types, and the proportion of land-cover types in the NLCD that are similar to managed clearings. Our study reveals that managed clearings are the most common land cover type in these cities, covering 28% of the total sampled land area- 6.2% higher than the total area of impervious surfaces. Managed clearings, when combined with forest cover, constitutes 69% of pervious surfaces in the sampled region. We observed variability in area estimates of managed clearings between the NAIP-derived and NLCD data. This suggests using high-resolution remote sensing imagery (e.g., NAIP) instead of modifying NLCD data for improved representation of spatial heterogeneity and mapping of managed clearings in urbanizing landscapes. Our findings also demonstrate the need to more carefully consider managed clearings and their critical ecological functions in landscape- to regional-scale studies of urbanizing ecosystems.

Uncertainties in mapping forest carbon in urban ecosystems.

Spatially explicit urban forest carbon estimation provides a baseline map for understanding the variation in forest vertical structure, informing sustainable forest management and urban planning. While high-resolution remote sensing has proven promising for carbon mapping in highly fragmented urban landscapes, data cost and availability are the major obstacle prohibiting accurate, consistent, and repeated measurement of forest carbon pools in cities. This study aims to evaluate the uncertainties of forest carbon estimation in response to the combined impacts of remote sensing data resolution and neighborhood spatial patterns in Charlotte, North Carolina. The remote sensing data for carbon mapping were resampled to a range of resolutions, i.e., LiDAR point cloud density - 5.8, 4.6, 2.3, and 1.2 pt s/m2, aerial optical NAIP (National Agricultural Imagery Program) imagery - 1, 5, 10, and 20 m. Urban spatial patterns were extracted to represent area, shape complexity, dispersion/interspersion, diversity, and connectivity of landscape patches across the residential neighborhoods with built-up densities from low, medium-low, medium-high, to high. Through statistical analyses, we found that changing remote sensing data resolution introduced noticeable uncertainties (variation) in forest carbon estimation at the neighborhood level. Higher uncertainties were caused by the change of LiDAR point density (causing 8.7-11.0% of variation) than changing NAIP image resolution (causing 6.2-8.6% of variation). For both LiDAR and NAIP, urban neighborhoods with a higher degree of anthropogenic disturbance unveiled a higher level of uncertainty in carbon mapping. However, LiDAR-based results were more likely to be affected by landscape patch connectivity, and the NAIP-based estimation was found to be significantly influenced by the complexity of patch shape.