Morphometric analysis of differently degraded simple craters on the moon

The main focus of this PhD research is the morphologic characterization of simple impact craters on lunar maria in order to find out a correlation between craters morphological degradation and absolute model ages of the surfaces where they were emplaced. Crater degradation can be indeed used to constrain the chronological evolution of planetary surfaces. The crater degradation is usually retrieved through visual inspection by subdividing craters into 4 classes: C1 represents the freshest ones, C2 are the ones with the first evidence of degradation (smoothed rim), C3 and C4 are related to morphologies ranging from heavily eroded to totally flattened respectively [Arthur, 1963]. We firstly conducted a morphometric analysis of craters representative of the four classes starting from the freshest one represented by the Linné crater. Craters were chosen on a homogeneous geological unit, the S28 unit in mare Serenitatis, with an absolute model age of 2.84 Gy [Hiesinger et al., 2011]. This analysis allowed us to establish the thresholds of mean slope from craters inner wall, in order to constrain the morphometric characterization of the four degradation classes. Successively we have extracted all impact craters (383) from a unique geological unit and we have defined the morphologic relationships among the degradation classes in function of the craters diameters. Finally, we expanded our analysis to six lunar maria, considering six lunar maria with different average absolute model ages, in order to perform this analysis with the wider range of ages. For each mare we considered a unique surface (dataset) derived from the merging of geological units with similar absolute model ages within the basin, in order to guarantee the most homogeneous possible surfaces, both in terms of impact rheology and absolute age. From the six surfaces we have extracted inner wall mean slopes from over 1000 impact craters. The mean slope values of the inner walls have shown a relation between crater morphology and the absolute model ages of the geological units where they are located. Older basins are characterized by craters with lower mean slope values, suggesting a dominance of older craters in their population, whereas the younger units have shown higher mean slope values of their simple craters, suggesting a population dominated by recent impacts. This tendency is the expression of the morphological alteration strictly connected to the lunar maria age. Since the geomorphometry of impact craters is influenced by the absolute age of the target area, we have constrained potential isochrones by fixing absolute age thresholds based on the morphological variations of impact craters

Forest Pathology and Entomology

The 22 papers that make up this Special Issue deal with pathogen and pest impact on forest health, from the diagnosis to the surveillance of causative agents, from the study of parasites’ biological, epidemiological, and ecological traits to their correct taxonomy and classification, and from disease and pest monitoring to sustainable control strategies

Changing States: Using State-and-Transition Models to Evaluate Channel Evolution Following Dam Removal Along the Clark Fork River, Montana

Located just east of Missoula, Montana, Milltown Dam stood from 1908 to 2008 immediately downstream of the Clark Fork River’s confluence with the Blackfoot River. After the discovery of arsenic-contaminated groundwater in the nearby community of Milltown, as well as extensive deposits of contaminated sediment in the dam’s upstream reservoir, in 1981, the area was designated a Superfund site – along with much of the Upper Clark Fork Watershed. This motivated the eventual decision to remove the dam, perform environmental remediation, and reconstruct approximately five kilometers of the Clark Fork River and its floodplain. This study is part conceptual and part empirical. It describes a state-and-transition framework equipped to investigate channel evolution as well as the adjustment trajectories of other socio-biophysical landscapes. This framework is then applied to understand the post-restoration channel evolution of the Clark Fork River’s mainstem, secondary channels, and floodplain. Adopting a state-and-transition framework to conceptualize landscape evolution lets environmental managers more effectively anticipate river response under multiple disturbence scenarios and therefore use more improvisational and adaptive management techniques that do not attempt to guide the landscape toward a single and permanent end state. State-and-transition models can also be used to highlight the spatially explicit patterns of complex biophysical response. The state-and-transition models developed for the Clark Fork River demonstrate the possibility of multiple evolutionary trajectories. Neither the secondary channels nor the main channel have responded in a linear, monotonic fashion, and future responses will be contingent upon hydrogeomorphic and climatic variability and chance disturbances. The biogeomorphic adjustments observed so far suggest divergent evolutionary trajectories and that in some instances the long-term fates of the mainstem, floodplain, and secondary channels are inescapably enmeshed with one another

An Analysis of Fluvial Geomorphology Parameters Affecting Meander Migration and Dynamic Equilibrium of the White River in Arkansas

An analysis of a multitude of fluvial and morphological parameters was conducted to assess the current stability conditions of various White River reaches and to accentuate the contributions imparted by these parameters to the internal processes that governed the dynamic equilibrium within these reaches. The initial step involved the extractions and computations of pertinent fluvial and morphological parameters from the HEC-RAS Model and ArcGIS.Channel stability assessment emphasized three methodologies, namely stability assessment through parametric correlations between fluvial and morphological parameters; stability evaluation with the Rosgen Stream Classification System; and stability estimation through sediment analyses and sediment related parametric correlations. Morphological assessment implementing the Rosgen Stream Classification (RSC) system consisted of four inventory levels of classification. Sediment analyses conducted by implementing several sediment transport functions utilized the dominant bed materials attained from sieve analyses of approximately seven hundred soil samples collected from the channels of various ‘reference’ reaches

Cinderella River: The evolving narrative of the River Lee

This is an exploration of the River Lee from its source above Luton to where it meets the Thames at Leamouth. The context is the AHRC funded Hydrocitizenship programme that aimed to explore the evolving relationship between communities and water through research by eight academic partners across four distinct case study sites across the UK. These are Shipley, Yorkshire, Borth, Mid Wales, Bristol and the Lee Valley. My strategy was to walk the river to gain insight into how it is managed along its entire course and to explore the intricacies of a waterway that has to function as a navigation, source of potable water, drain, flood relief facility, biodiverse habitat, recreational amenity and visitor attraction, yet retain a sense of integrity

Influence of Rain on Vision-Based Algorithms in the Automotive Domain

The Automotive domain is a highly regulated domain with stringent requirements that characterize automotive systems’ performance and safety. Automotive applications are required to operate under all driving conditions and meet high levels of safety standards. Vision-based systems in the automotive domain are accordingly required to operate at all weather conditions, favorable or adverse. Rain is one of the most common types of adverse weather conditions that reduce quality images used in vision-based algorithms. Rain can be observed in an image in two forms, falling rain streaks or adherent raindrops. Both forms corrupt the input images and degrade the performance of vision-based algorithms. This dissertation describes the work we did to study the effect of rain on the quality images and the target vision systems that use them as the main input. To study falling rain, we developed a framework for simulating failing rain streaks. We also developed a de-raining algorithm that detects and removes rain streaks from the images. We studied the relation between image degradation due to adherent raindrops and the performance of the target vision algorithm and provided quantitive metrics to describe such a relation. We developed an adherent raindrop simulator that generates synthetic rained images, by adding generated raindrops to rain-free images. We used this simulator to generate rained image datasets, which we used to train some vision algorithms and evaluate the feasibility of using transfer-learning to improve DNN-based vision algorithms to improve performance under rainy conditions.Ph.D.College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttp://deepblue.lib.umich.edu/bitstream/2027.42/170924/1/Yazan Hamzeh final dissertation.pdfDescription of Yazan Hamzeh final dissertation.pdf : Dissertatio

Estimation of historic salmon populations and its application to contemporary salmon conservation

Populations of wild Pacific salmon and steelhead (Oncorhynchus sp.) in the eastern Pacific Rim have experienced significant declines in abundance and associated genetic and life history diversity over the course of the twentieth century (Nehlson et al 1991, Slaney et al 1996, Myers et al 1998, Lichatowich 1999). In the Pacific Northwest of the United States, declines in the abundance of most populations accelerated in the last two decades of the century and have continued into the first two decades of the twenty-first (Busby et al 1996, Myers et al. 1998, Good et al.2005, Hard et al. 2007, Ford et al. 2011)

Ecosystem Services, Green Infrastructure and Spatial Planning

National governments hardly identify their ecological networks or make an effort to integrate them into their spatial policies and plans. Under this perspective, an important scientific and technical issue is to focus on preserving corridors for enabling species mobility and on achieving connectivity between natural protected areas. This Special Issue takes a step forward insofar as it aims at proposing a theoretical and methodological discussion on the definition and implementation of ecological networks that provide a wide range of ecosystem services