MEMO: Dataset and Methods for Robust Multimodal Retinal Image Registration with Large or Small Vessel Density Differences

The measurement of retinal blood flow (RBF) in capillaries can provide a powerful biomarker for the early diagnosis and treatment of ocular diseases. However, no single modality can determine capillary flowrates with high precision. Combining erythrocyte-mediated angiography (EMA) with optical coherence tomography angiography (OCTA) has the potential to achieve this goal, as EMA can measure the absolute 2D RBF of retinal microvasculature and OCTA can provide the 3D structural images of capillaries. However, multimodal retinal image registration between these two modalities remains largely unexplored. To fill this gap, we establish MEMO, the first public multimodal EMA and OCTA retinal image dataset. A unique challenge in multimodal retinal image registration between these modalities is the relatively large difference in vessel density (VD). To address this challenge, we propose a segmentation-based deep-learning framework (VDD-Reg) and a new evaluation metric (MSD), which provide robust results despite differences in vessel density. VDD-Reg consists of a vessel segmentation module and a registration module. To train the vessel segmentation module, we further designed a two-stage semi-supervised learning framework (LVD-Seg) combining supervised and unsupervised losses. We demonstrate that VDD-Reg outperforms baseline methods quantitatively and qualitatively for cases of both small VD differences (using the CF-FA dataset) and large VD differences (using our MEMO dataset). Moreover, VDD-Reg requires as few as three annotated vessel segmentation masks to maintain its accuracy, demonstrating its feasibility.Comment: Submitted to IEEE JBH

Assessing Suicide Risk and Emotional Distress in Chinese Social Media: A Text Mining and Machine Learning Study

published_or_final_versio

Women\u27s Studies Center Annual Report 2006-2007

https://digitalcommons.fiu.edu/cwgs-annualreports/1004/thumbnail.jp

A hybrid simulation approach to modelling the impact of public interventions on poverty

*An earlier version of this article has been presented in ICABE 2019 www.icabe.grPurpose: The aim of the article is to present the concept of a hybrid simulation model to study the impact of public intervention on the level of poverty at the local, regional and national levels. Design/Methodology/Approach: The proposed model is the hybrid of two computer simulation methods Agent-Based Simulation (ABS) and System Dynamics (SD). Findings: Counteracting the phenomenon of poverty is one of the tasks of public administration units. Various tools and instruments can be used to fight poverty, as a part of numerous programs financed from public funds, but their implementation should be preceded by a thorough analysis of the effects arising after their application. This is not easy, because the phenomenon of poverty is very complex, it results from the arrangement of many interrelated elements, and the outcomes of actions are visible only after a longer period of time. This system is characterized by the heterogeneity of elements. Some of them are on a macro scale (e.g. GDP level, labour market), while others refer to the micro scale (e.g. households and their members). Building a model of households requires the use of a method that allows to reflect the behaviour and decision-making rules of individuals and the interaction between them in a disaggregated form. Agent-Based Simulation (ABS) is such a method. On the other hand, modelling elements occurring in the macro scale, where we usually deal with aggregate quantities, is best matched by System Dynamics (SD) simulation method, which allows for reflecting dynamic behaviour through feedback loops. Practical Implications: The proposed concept can be used both by public administration units at various levels as well as by scientists - to conduct socio-economic research. Originality/Value: The applied simulation approach allows to capture the interrelations between the modelled effects in a dynamic manner for a long-time horizon, which is extremely important in the case of public management activities.peer-reviewe

Glacial History of the North Atlantic Marine Snail, Littorina saxatilis, Inferred from Distribution of Mitochondrial DNA Lineages

The North Atlantic intertidal gastropod, Littorina saxatilis (Olivi, 1792), exhibits extreme morphological variation between and within geographic regions and has become a model for studies of local adaptation; yet a comprehensive analysis of the species' phylogeography is lacking. Here, we examine phylogeographic patterns of the species' populations in the North Atlantic and one remote Mediterranean population using sequence variation in a fragment of the mitochondrial cytochrome b gene (607 bp). We found that, as opposed to many other rocky intertidal species, L. saxatilis has likely had a long and continuous history in the Northwest Atlantic, including survival during the last glacial maximum (LGM), possibly in two refugia. In the Northeast Atlantic, several areas likely harboured refugial populations that recolonized different parts of this region after glacial retreat, resulting in strong population structure. However, the outlying monomorphic Venetian population is likely a recent anthropogenic introduction from northern Europe and not a remnant of an earlier wider distribution in the Mediterranean Sea. Overall, our detailed phylogeography of L. saxatilis adds an important piece to the understanding of Pleistocene history in North Atlantic marine biota as well as being the first study to describe the species' evolutionary history in its natural range. The latter contribution is noteworthy because the snail has recently become an important model species for understanding evolutionary processes of speciation; thus our work provides integral information for such endeavours

Upstream Ultra‐Low Frequency Waves Observed by MESSENGER’s Magnetometer: Implications for Particle Acceleration at Mercury’s Bow Shock

We perform the first statistical analysis of the main properties of waves observed in the 0.05–0.41 Hz frequency range in the Hermean foreshock by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Magnetometer. Although we find similar polarization properties to the “30 s” waves observed at the Earth’s foreshock, the normalized wave amplitude (δB/|B0|∼0.2) and occurrence rate (∼0.5%) are much smaller. This could be associated with relatively lower backstreaming proton fluxes, the smaller foreshock size and/or less stable solar wind (SW) conditions around Mercury. Furthermore, we estimate that the speed of resonant backstreaming protons in the SW reference frame (likely source for these waves) ranges between 0.95 and 2.6 times the SW speed. The closeness between this range and what is observed at other planetary foreshocks suggests that similar acceleration processes are responsible for this energetic population and might be present in the shocks of exoplanets.Key PointsWe perform the first statistical analysis (4,536 events) of the main properties of the lowest‐frequency waves in the Hermean foreshockSmall normalized wave amplitude (0.2) and occurrence (0.5%) are likely due to low backstreaming proton flux and variable external conditionsThe normalized backstreaming protons speed (∼0.95–2.6) suggests similar acceleration processes occur at several planetary shocksPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155492/1/grl60476.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155492/2/grl60476_am.pd

Pursuing pasture tolerance and resilience through species with different functional traits and soil-plant-water interactions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Manawatu, New Zealand

Higher stability, persistence and yield can be achieved through increasing the biodiversity of pasture plants. The combination of species with different functional traits confers niche differentiation (e.g. different root depth). Otherwise species compete for the same resources in the same location and time. In diverse pasture, agricultural needs should overlap between species, enhancing species survival during critical periods. Productive ecosystems with low complexity (low plant functional diversity) show more the negative impacts of climate change, being less stable through the stress periods. Bromus valdivianus Phil. is regarded as having high potential for grazing systems, due to its high yield and good nutritive quality. It also has high tolerance to periods of soil water restriction, maintaining a higher growth rate during summer in comparison to Lolium perenne L. Alongside L. perenne, B. valdivianus co-dominates permanent perennial pastures in the South of Chile, indicating that it is a good competitor in mixed cool-temperate pastures. However, key parameters associated with recovery from defoliation, such as watersoluble carbohydrate (WSC) reserves, growth rate, tiller number and persistence, are unknown for B. valdivianus. Therefore, the first step in this thesis was to determine these defoliation criteria in relation to similar defoliation criteria of other highly productive species, L. perenne and Plantago lanceolata, to determine if and when any overlap occurred. This thesis consisted of three main experiments, which cover the physiological, morphological and competitive traits of B. valdivianus. The first experiment was designed to determine a theoretical optimum defoliation interval for B. valdivianus, and it was concluded that defoliation at leaf stage 4 (LS-4) was the optimum defoliation in terms of highest shoot and root growth rates, and accumulation of WSC. The second experiment was designed to determine the resilience and tolerance between monocultures and mixtures of B. valdivianus, L. perenne and P. lanceolata. All three species were defoliated when B. valdivianus reached LS-4, which coincided with approximately 3.5 regrowth leaves/tiller for L. perenne, and over 6 leaves/plant for P. lanceolata. Measurements included biomass production across critical periods, botanical composition, physiological response against water stress (waterlogging and soil water restriction) and water uptake at different depths, and it was concluded that a more diverse pasture (B. valdivianus + L. perenne + P. lanceolata) maintained higher biomass under soil water restriction and also had a more effective water uptake from the soil profile. The third experiment was designed to determine the tiller population dynamics, photosynthetic carbon fixation capacity (PCFC) and competitive ability of B. valdivianus in relation to L. perenne. It was concluded that L. perenne was a better competitor than B. valdivianus, however, B. valdivianus was able to recover its tiller population during a period of soil water restriction and reached a full recovery at the end of the experimental period. Also, a B. valdivianus + L. perenne mixed pasture had the highest values for PCFC during the waterlogging and soil water restriction periods. Pasture plants such as B. valdivianus and P. lanceolata can access water from deeper in the soil than L. perenne, having a direct effect on their physiological traits. Water accessibility (root depth) plays a key role in maintaining their photosynthesis, production, and improving their survival, during periods of soil water restriction, relative to L. perenne. On the other hand, L. perenne tolerate waterlogging and maintain a relatively high growth rates during winter. Pasture establishment and performance, in a climate with dry and wet seasons and in soils with a high percentage of silt and/or clay (low gas permeability), is related to species tolerance to drought and waterlogging conditions. Thus, increasing species diversity is a good strategy that confers stability to the pastoral ecosystem, especially when global warming has enhanced droughts and unpredictable rain events. Mixtures of L. perenne + T. repens + P. lanceolata or L. perenne + T. repens + B. valdivianus can reach higher growth rates during water restriction periods, in comparison to L. perenne + T. repens pastures, along with relatively high growth rates during winter. Therefore, combining species with the aim of complementary resources uptake, and depending on the contribution of each species within the pasture, will change the seasonal herbage growth rate under the stress periods. However, to keep a great contribution of the desirables pasture species it is essential to use a defoliation criterion that allow them to replenish its water soluble carbohydrates, only then, the persistence, survival and yield of the pasture and the desirables species within it will be maximized

A Facilitation Workshop for the Implementation Stage: A Case Study in health care

Research on facilitation in discrete event simulation (DES) is gathering pace but there is still a need to put forward real examples to explain the process to newcomers. Most of the research has focussed on facilitation in the initial stages of the simulation modelling process. In this paper we focus on one of the postmodel coding stages. More specifically we focus on the implementation stage, the final stage in the modelling process. The primary contributions of this paper are the description of the process followed and the introduction of tools that can be used during this stage to support workshop activities. A real case study is provided describing the sequence of the interactions undertaken in the workshop. Extracts from the transcripts are also included, with the view to bringing evidence of the stakeholders’ involvement and their mood during the workshop. The paper concludes with a discussion on the process followed and the importance of using tools in this stage