Power scaling of an extreme ultraviolet light source for future lithography

For future lithography applications, high-power extreme ultraviolet (EUV) light sources are needed at a central wavelength of 13.5 nm within 2% bandwidth. We have demonstrated that from a physics point of view the Philips alpha-prototype source concept is scalable up to the power levels required for high-volume manufacturing (HVM) purposes. Scalability is shown both in frequency, up to 100 kHz, and pulse energy, up to 55 mJ collectable EUV per pulse, which allows us to find an optimal working point for future HVM sources within a wide parameter space. (C) 2008 American Institute of Physics

Context Data Categories and Privacy Model for Mobile Data Collection Apps

Context-aware applications stemming from diverse fields like mobile health, recommender systems, and mobile commerce potentially benefit from knowing aspects of the user's personality. As filling out personality questionnaires is tedious, we propose the prediction of the user's personality from smartphone sensor and usage data. In order to collect data for researching the relationship between smartphone data and personality, we developed the Android app TYDR (Track Your Daily Routine) which tracks smartphone data and utilizes psychometric personality questionnaires. With TYDR, we track a larger variety of smartphone data than similar existing apps, including metadata on notifications, photos taken, and music played back by the user. For the development of TYDR, we introduce a general context data model consisting of four categories that focus on the user's different types of interactions with the smartphone: physical conditions and activity, device status and usage, core functions usage, and app usage. On top of this, we develop the privacy model PM-MoDaC specifically for apps related to the collection of mobile data, consisting of nine proposed privacy measures. We present the implementation of all of those measures in TYDR. Although the utilization of the user's personality based on the usage of his or her smartphone is a challenging endeavor, it seems to be a promising approach for various types of context-aware mobile applications.Comment: Accepted for publication at the 15th International Conference on Mobile Systems and Pervasive Computing (MobiSPC 2018

TYDR - Track Your Daily Routine. Android App for Tracking Smartphone Sensor and Usage Data

We present the Android app TYDR (Track Your Daily Routine) which tracks smartphone sensor and usage data and utilizes standardized psychometric personality questionnaires. With the app, we aim at collecting data for researching correlations between the tracked smartphone data and the user's personality in order to predict personality from smartphone data. In this paper, we highlight our approaches in addressing the challenges in developing such an app. We optimize the tracking of sensor data by assessing the trade-off of size of data and battery consumption and granularity of the stored information. Our user interface is designed to incentivize users to install the app and fill out questionnaires. TYDR processes and visualizes the tracked sensor and usage data as well as the results of the personality questionnaires. When developing an app that will be used in psychological studies, requirements posed by ethics commissions / institutional review boards and data protection officials have to be met. We detail our approaches concerning those requirements regarding the anonymized storing of user data, informing the users about the data collection, and enabling an opt-out option. We present our process for anonymized data storing while still being able to identify individual users who successfully completed a psychological study with the app.Comment: Accepted for publication at the 5th IEEE/ACM International Conference on Mobile Software Engineering and Systems (MOBILESoft '18

The Potential for Augmented Reality to Bring Balance betweenthe Ease of Pedestrian Navigation and the Acquisition of Spatial Knowledge

Being completely lost in an unfamiliar environment can be inconvenient, stressful and, at times, even dangerous. Maps are the traditional tools used for guidance but many people find maps difficult to use. In recent years, new tools like outdoor Augmented Reality (AR) have become available which allow virtual navigation cues to be directly overlaid on the real world, potentially overcoming the limitations of maps. However, it has been hypothesized that lower effort invested in processing navigation guidance may lead to diminished spatial knowledge (SK) thereby making users of such navigation tools far more vulnerable to getting lost should the tools fail for any reason. This thesis explores the research question of how AR and maps compare as tools for pedestrian navigation guidance as well as for SK acquisition and if there is a potential for AR tools be developed that would balance the two. We present a series of studies to better understand the consequences of using AR in a pedestrian navigation tool. The first two studies compared time-on-task performance and user preferences for AR and Map navigation interfaces on an outdoor navigation task. The results were not aligned with expectations, which led us to build a controlled testing environment for comparing AR and map navigation. Using this simulated setting, our third study verified the assumption that AR can indeed result in more efficient navigation performance and it supported the hypothesis that this would come at the cost of weaker SK. In our fourth study, we used a dual task design to compare the relative cognitive resources required by map and AR interfaces. The quantitative data collected indicated that users could potentially accept additional workload designed to improve SK without incurring significantly more effort. Our fifth and final study explored an interface with additional AR cues that could potentially balance navigation guidance with SK acquisition. The contributions of this thesis include insights into performance issues relating to AR, a classification of user types based on navigation tool usage behavior, a testbed for simulating perfect AR tracking in a virtual setting, objective measures for determining route knowledge, the capacity that pedestrian navigation tool users may have for performing additional tasks, and guidelines that would be helpful in the design of pedestrian navigation tools

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Land-use effects on insect herbivores and their interactions with plants: a functional approach

Biodiversity is decreasing globally at an alarming rate, with land-use change and intensification being main drivers. Europe has a long history of land use and vast areas of forests have been transformed to agricultural lands over the last millennia. Today, forests and grasslands, two important and insect species rich ecosystems in temperate regions, are experiencing intensified land use and are embedded in landscapes increasingly shaped by humans. Insect herbivores, which depend on plants as food sources during at least part of their life cycles, account for a large share of insect communities. They contribute strongly to ecosystem functions such as in-vertebrate herbivory, which ensures the cycling of nutrients and energy within terrestrial ecosystems. Herbivore communities have repeatedly been shown to be among the functional groups most susceptible to land-use intensification. How different aspects of land use, such as land-use type at different spatial scales, affect herbivore communities, is still not well understood. Here, different functional approaches are used to investigate mechanisms underlying the assembly of herbivore communities in forests and grasslands that are differently exposed to land use. The first three chapters of this thesis were conducted in the Biodiversity Exploratories project, which comprises of 300 forest and grassland study plots located in three regions of Germany, covering land-use intensity gradients typical for the respective ecosystems. Chapter I investigates how land use at different spatial scales (local, landscape) affects the composition and diversity of insect herbivore communities in grasslands by using a trait-based approach. It shows that intensive local land use results in herbivore communities characterised by smaller species with longer wings, indicating the functional role of disturbance avoidance in shaping the trait composition of herbivore communities. At the same time, several traits that are related to microhabitat use were significantly related to land use at landscape scale, implying that land-scape-level species pools are crucial in determining local communities. Finally, while local trait diversity was not related to land-use intensity, among-site trait diversity (β-diversity) was significantly reduced by local land use. Thus, intensive local land use resulted in functional homog-nisation of insect herbivore communities, which might have profound consequences for ecosystem multifunctionality at the landscape scale. Chapter II examines plant–herbivore interaction networks to understand how the structure of these networks is related to their stability, i.e. robustness, and how they are shaped by land use. By merging data from plant and herbivore abundances with a literature-derived interaction data base, networks were constructed for 289 forest and grassland plots. Across ecosystems, network size and nestedness were positively associated with network robustness. In forests, network size was particularly important for robustness, but significantly reduced in unmanaged beech forests due to a lack of understory vegetation. In grasslands, moderate grazing was found to maximise network robustness. These new insights show ways to manage both forests and grasslands towards more stable plant–herbivore communities. In Chapter III, invertebrate herbivory was assessed for the most abundant plant species on 297 forest and grassland plots to understand how land use affects herbivory rates by altering plant and herbivore communities. Across both ecosystems, herbivory rates decreased along land-use intensity gradients. In forests, this was partly explained by a shift from broadleaf to conifer species in the tree layer, which was accompanied by a decrease of leaf palatability. In grasslands, the intensity of all three land-use components (mowing, grazing, fertilisation) was negatively associated with herbivory rates. In contrast to forests, changes in plant species com-position only weakly explained these changes, suggesting that the observed effects on herbivory rates were likely mediated by other plant and herbivore community characteristics. Reduced herbivory might imply a reduction in nutrient and energy cycling in these systems, which could have cascading effects on other trophic levels and thus contribute greatly to biodiversity loss. In Chapter IV, the success of different restoration measures to restore semi-natural grass-lands from previously intensively used grasslands in Switzerland was evaluated. Restoration measures differed in their invasiveness from mere removal of harvested biomass to removal of the topsoil layer and subsequent seeding of plant propagules. Twenty-two years after the establishment of the restoration measures, insect herbivore communities were found to resemble the target state in terms of composition and diversity, both taxonomically and functionally. However, restoration measures involving topsoil removal were found to be most effective, especially in re-establishing species characterised by traits known to be susceptible to intensive land use. Thus, measures involving topsoil removal are recommended to restore taxonomically and functionally divers semi-natural grasslands. This thesis provides novel insights into the mechanisms underlying the relationships be-tween land use, insect herbivore communities and herbivory and shows ways to reduce negative impacts of intensive land use. Based on robust observational data from grasslands and forests, crucial pathways via changes in plant communities and plant–herbivore interactions, as well as changes in herbivore traits and trait syndromes, could be identified. The documented relation-ships were complex and may differ between ecosystems, land-use modes or spatial scales. Nevertheless, I was able to discover some general relationships that open up avenues for landscape management aimed at sustaining diverse insect communities while meeting the various demands of human societies on these landscapes

Frequency and duration of daily smartphone usage in relation to personality traits

Objectives: Daily life behaviour can be studied by smart mobile devices. The current study investigated associations between personality traits and smartphone usage in daily routine. Methods: 526 participants used the Track Your Daily Routine smartphone app (TYDR) for 48 days, on average (SD = 63.2, range 2 to 304). The Big Five Inventory 2 (BFI-2) was deployed to measure personality traits (Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness). We analyzed associations between personality traits and two indicators of smartphone usage: number of wakeups per day and session duration. Results: Participants reached for a smartphone more frequently during weekdays with shorter duration of usage compared to weekends. Younger people used their smartphones more often but with a shorter duration than older people. Female participants spent more time using smartphone per session than male participants. Extraversion and neuroticism were associated with more frequent checking of the phone per day while conscientiousness was associated with a shorter duration of the session per day. Conclusions: Frequency and duration of daily smartphone usage is associated with personality traits and participants demographics (age, gender). Implications for future research are discussed

Tracking sucking herbivory with nitrogen isotope labelling: Lessons from an individual trait-based approach

Response and effect traits help to understand how changes in ecological communities (e.g. in response to land use) relate to changes in ecosystem functioning. In grasslands, plants and insect herbivores are involved in many ecosystem processes such as herbivory and plant biomass production. Simultaneous changes in the trait composition of both plants and herbivores should affect herbivory rates, with consequences for plant growth and potentially biomass production. The mechanisms underlying these links are little understood for grasses and sucking insects, which build a major part of grassland communities. In a mesocosm experiment, we manipulated the composition of grasses and sucking herbivores (Hemiptera) to study the role of plant traits, herbivore traits and their interaction on herbivory and plant growth. Because sucking herbivory is generally difficult to quantify, we developed a novel experimental setting, in which we labelled plants with 15N isotope. This allowed to quantify 15N uptake and thus sucking rates of individuals. We found that herbivory and simultaneous plant growth reduction are most strongly linked to herbivore species identity. Unexpectedly, herbivory did not increase with herbivore size, but was highest for small species and for thin-bodied Heteroptera. Additionally, herbivory and plant growth reduction depended on the interacting herbivore and plant species, indicating trait matching, which could, however, not be explained with commonly used traits. This indicates that mechanisms linking ecological communities and ecosystem processes are highly context-specific. To understand how global change affects ecosystem functioning, studies need to cover all functionally relevant groups, including plant sap suckers.ISSN:1439-1791ISSN:1618-008