Keratoconus is an eye disease that manifests as progressive thinning and steepening of the cornea. While there is no singular cause for keratoconus, both genetic and environmental factors have been proposed to influence the onset and progression. This review aims to explore the pathogenesis, identification, classification, and treatment of this corneal disease. Since early detection is essential in treatment success, various imaging methods have been developed to analyze multiple aspects of the corneal surface. Keratoconus can be identified with a reflection based system, elevation based system, as well as a combination of the two. Once diagnosed, the Belin ABCD classification can be used to monitor the stage of keratoconus and treat it accordingly. Current treatment options prioritize halting disease progression with corneal crosslinking before considering visual rehabilitation. Individuals with mild keratoconus can improve vision with non-surgical options such as spectacles and contact lenses. As the disease progresses, patients may need surgical intervention such as intrastromal corneal ring segments or photorefractive keratectomy (PRK). In advanced keratoconus cases, the cornea may need to be replaced with partial or full-thickness keratoplasty. The goal of this review is to evaluate the more current treatment options that have become available today.

In comparison to the southern pine beetle (SPB), (Dendroctonus frontalis Zimmermann), less is known about the three species of Ips bark beetles; the six-spined engraver, Ips calligraphus (Germar); the eastern five-spined engraver, Ips grandicollis (Eichhoff); and the small southern pine engraver, Ips avulses (Eichhoff). Ips commonly enter a stand following the first commercial thinning, feeding on slash and stressed individuals. However, the factors that influence Ips severity are poorly understood. Therefore, this project was designed to study the seasonal effects of first commercial thinning operations on Ips activity in north Mississippi loblolly pine stands. Treatments represented the most commonly used thinning practices in this area (i.e., a fifth row harvest with select, a third row harvest with select, and control). Treatments were duplicated three times per site and two sites were utilized to compare Ips movement to harvesting season.

No description available.

Temperate deciduous forests of eastern North America are undergoing a long-term compositional shift from oak/hickory-dominated forests to maple/birch-dominated forests, resulting in decreased species diversity and more homogeneous understory communities. This shift is likely due to secondary regrowth after extensive logging and intensive fire suppression efforts that together allowed shade-tolerant but fire-intolerant species to flourish. Managers have more recently sought to use forest management practices to counteract this shift. Our aim in this study was to improve understanding of how prescribed burning and mechanical tree thinning shape forest communities and the extent to which they favor declining species and communities of temperate eastern deciduous forest. We conducted our study at Fort Indiantown Gap National Guard Training Center in south-central Pennsylvania. Prescribed burning and mechanical thinning have been conducted onsite since 2003. Forestry plots were surveyed in 2003 just prior to management implementation and again about ten years after intensive management began, during 2013-2014. The data collected at forestry plots, including number of stems, tree diameter at breast height, management activities undertaken at the plot, and other environmental characteristics were analyzed using model selection and generalized linear mixed models. A broader community analysis was then conducted using non-metric multidimensional scaling and permutational multivariate analysis of variance (PERMANOVA) analyses. Specifically, we analyzed tree species persistence, changes in tree basal area, changes in the abundance of tree stems, and changes in the the distribution of basal area and stems within 16 tree species targeted for management and throughout the forest community as a whole following management action. Burning and thinning both had significant effects on tree species persistence, basal area, and stem abundance. The interaction of the two management techniques was rarely significant, but since thinning and burning affected different species of trees, the two management practices were complementary. At a whole community level, management by both burning and thinning shifted the forest composition back toward an oak/hickory-dominated forest, and without such management the shift to a maple/birch-dominated forest is likely to continue. / Biology

No / This paper describes a novel procedure for thinning binary text images by generating graphical representations of words within the image. A smoothed polygonal approximation of the boundaries of each word is first decomposed into a set of contiguous triangles. Each triangle is then classified into one of only three possible types from which a graph is generated that represents the topological features of the object. Joining graph points with straight lines generates a final polygon skeleton that, by construction, is one pixel wide and fully connected. Results of applying the procedure to thinning Arabic and English handwriting are presented. Comparisons of skeleton structure and execution time with results from alternative techniques are also presented. The procedure is considerably faster than the alternatives tested when the image resolution is greater than 600 dpi and the graphical representation often needed in subsequent recognition steps is available without further processing.

With post-bloom chemical fruit thinning responses being heavily influenced by tree carbohydrate reserves and weather conditions, there is a need for alternative thinning practices such as chemical blossom thinning in the Mid-Atlantic apple growing region. This project sought to 1) evaluate timing strategies for lime sulfur + stylet-oil blossom thinning sprays and 2) screen chemical agents for their suitability and efficacy as blossom thinners. In the first study, two 'Gala'/'M.9' blocks in different states (North Carolina and Virginia) were utilized in 2019 to compare between pollen tube growth model-guided blossom thinning sprays and those that are based on fixed time intervals between the initial application and subsequent thinning sprays. It was generally found that model-guided blossom thinning sprays and sprays applied at 20% open bloom and 48 hours after reduced fruit set, crop load, and improved fruit weight. In the second study, a 'Honeycrisp'/'B.9' and 'Cripps Pink'/'M.9' apple block in Virginia were used in 2018 and 2019 to evaluate multiple chemical agents with and without stylet-oil. Most of the treatments under-thinned compared to untreated control trees. However, it was determined that ammonium thiosulfate with and without stylet-oil was the most effective thinning agent. Potassium bicarbonate + stylet-oil was observed to cause excessive fruit russeting and phytotoxicity. This project demonstrated that optimum apple crop loads can be obtained if lime sulfur + stylet-oil blossom thinning sprays are applied at the proper time, and that multiple chemical agents offer potential use for chemical blossom thinning in the Mid-Atlantic region / Master of Science in Life Sciences / For apple trees to produce high quality fruit, a proportion of the flowers and/or fruit must be removed in a practice known as "thinning". Chemical blossom thinning is a relatively new method of thinning in the Mid-Atlantic apple growing region. This project sought to 1) evaluate spray timing of blossom thinning sprays and 2) evaluate different chemicals for their suitability in blossom thinning. In the first study, two 'Gala' apple orchards in two states (North Carolina and Virginia) were utilized in 2019 to compare a computer model-guided spray timing to structured spray timings based on the amount of time between the first and second sprays. It was found that the model-guided sprays, and sprays occurring once 20% of the blossoms had opened and reapplied 48 hours after, were the most effective in thinning the flowers. In the second part of the study, a 'Honeycrisp' orchard and a 'Cripps Pink' orchard in Virginia were used in 2018 and 2019 to evaluate different chemicals for their potential as blossom thinners. Unfortunately, most of the treatments did not achieve sufficient thinning results compared to untreated trees. However, it was determined that ammonium thiosulfate with and without stylet-oil was the most effective thinning chemical. Potassium bicarbonate with stylet-oil was found to cause excessive injury to the fruit and foliage. This project demonstrated that blossom thinning can be effective when the sprays are applied at the correct time and that multiple chemical agents offer potential for blossom thinning in the Mid-Atlantic.

If a landowner‘s main objective is to maximize his/her profits from planted forest investments, questions such as when and where exactly they should fertilize, thin and clearcut must be answered. We take advantage of an experiment established in 5 different states in the US South. Forest inventory data was collected for different combinations of thinning densities where some of them received fertilization. We use the Land Expectation Value methodology where our assumptions are the infinite amount of Pine rotations while costs and stumpage prices are known and constant, and markets are perfect. One of the main results we found is that fertilization has a decreasing marginal benefit on site index quality. / M.S. / If the landowner‘s main objective is to maximize profit from forest investments, questions such as when and where they should fertilize, thin and clearcut must be answered. Fertilization‘s main objective is to provide essential nutrients for tree growth. Thinnings have two main objectives: a source of revenue in the middle of the forest rotation by selling the thinned trees and secondly to open space to the residual trees so they grown in diameter and gain value. We analyze how thinning and fertilization impact forest management from an economic perspective by checking their benefits and costs to landowners. We found that for low site index, fertilization has a positive impact in the sense its benefit is greater than the fertilization application cost. For better site indices, the opposite is true. For those who want to maximize economic benefits from planted forests. we end up with recommendations of which type of thinning and fertilization should be done according to the landowner site quality.

Thinning is performed today with essentially two thinning methods, with strip-roads or stand-thinning machines. The result after thinning affects the stands future development. In this study, the two thinning methods was compared with regard to distribution of basal area, resulting damage, the distribution of stems, actual thinning intensity and the impact that these differences may provide in the future. The survey was conducted in Sundsvall, Sweden in two different stands where basal area- surfaces, number of stems, damage and thinning strength was measured. The result shows that stand-thinning machines produce less damage to the stems and a more even distribution of the basal area. The strip-road method carried out a thinning of excessive thinning intensity of 50 % compared to 30 % for stand-thinning method. From a quality point of view the stand-thinning machines performed a better result. These machines have a lower production (harvested volume per hour) which probably results in lower financial gains in thinnings. Keywords: stand-thinning, basal area, thinning strength, Vimek, soil damage.

Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 61-67). Also available via Humboldt Digital Scholar.

Med växande arealer som inte röjs, samt ett ökat intresse för skogsbränsleuttag, krävs utveckling av teknik och metoder för att kunna utvinna denna resurs. Genom att, från uppställningsplatser i stickväg, avverka träd i krankorridorer minskar antalet kranrörelser per träd. Detta minskar i sin tur den höga avverkningskostnaden i stamtäta, klena bestånd. I ett tallbestånd i södra Sverige undersöktes metoden krankorridorgallring. I transekter vinkelrätt från stickväg mättes höjd, brösthöjdsdiameter, stubbdiameter, stamantal, trädslagsblandning, stubbhöjder och skador, samt dess stickvägsavstånd. Detta beräknades sedan i Excel. Gallringskvoten var på 0,77, alltså ökade beståndets medeldiameter och höjd. Gallringsstyrkan låg på 53% med 61% avverkade träd i krankorridorer, resten i stickväg. Andelen skador var 1.5% och stubbhöjden 48 cm, inga av dessa kunde korreleras till stickvägsavståndet. Innan åtgärd stod endast 2267 stammar >3cm per hektar, bestånd med högre stamantal behövs för en bättre utvärdering av metoden. / With a growing number of unmanaged stands with a high number of stems per hectare and low diameters, and with growing interests in biomass extractions for fuel, development of proper technology and methods to extract these resources is required. By mechanical harvesting of trees in corridors, the number of crane movements per tree is decreased, resulting in lower harvest costs. In a pine stand in southern Sweden, this method of boom-corridor thinning was examined. This was done by measuring, perpendicular to the strip road, mean heights, breast height- and stump diameters, number of stems, tree species composition, stump heights and damages from thinning and later calculated in Excel. The relationship between harvested and standing tree diameters where 0,77, which can be compared to a heavy thinning from below. The thinning grade resulted in 53% with 61% trees harvested in boom-corridors. Damage percent resulted in 1.5% and the mean stump-height was 48 cm, none of these factors could be connected to their strip-road distance. Before thinning the number of stems was 2267 stems >3cm per hectare. For a better evaluation of the method, stands with higher number of stems would be required.