Smart Surrogate Widgets for Direct Volume Manipulation

Interaction is an essential aspect in volume visualization, yet common manipulation tools such as bounding boxes or clipping plane widgets provide rather crude tools as they neglect the complex structure of the underlying data. In this paper, we introduce a novel volume interaction approach based on smart widgets that are automatically placed directly into the data in a visibility-driven manner. By adapting to what the user actually sees, they act as proxies that allow for goal-oriented modifications while still providing an intuitive set of simple operations that is easy to control. In particular, our method is well-suited for direct manipulation scenarios such as touch screens, where traditional user interface elements commonly exhibit limited utility. To evaluate out approach we conducted a qualitative user study with nine participants with various backgrounds.acceptedVersio

Norovirus in Pacific Oysters : Insights into Molecular Viability Assays and Mitigation Strategies to Improve Food Safety

Som en av de vanligste årsakene til gastroenteritt, har norovirus (NoV) vært en belastning for pasienter, helsemyndigheter og samfunnet over hele verden. Patogenet overføres gjennom inntak av infektive viruspartikler. Mange matbårne NoV utbrudd har vært knyttet til konsum av rå skalldyr, og østers ser ofte ut til å være en ansvarlig matvare. NoV har vist seg å binde til østersens fordøyelsesvev via histo-blodgruppeantigener, til sialinsyre i gjeller og mantel, og kan til og med finnes i østershemocytter. Derfor akkumulerer østers lett NoV under filtrering og påvirker virusets persistens i perioder med depurering. For å sikre et trygt produkt er det nødvendig med metoder for å oppdage infeksiøse NoV. NoV er vanskelig å dyrke, så RT-qPCR er den vanligste metoden for NoV-screening, men metoden påviser også RNA fra ikke-intakte virus. Det første målet med dette arbeidet var å finne en effektiv molekylær analysemetode for å påvise intakte og dermed smittsomme virus. For å vurdere kapsidskade ble prøvene behandlet med enzym (RNase) eller interkalerende fargestoff (PMAxx). Når det gjelder genomskade, ble langdistanse PCR-analyse benyttet, siden denne metoden er i stand til å påvise skader i virus RNAet. Ett mål for arbeidet var også å undersøke effekten av ulike virusinaktiveringsmetoder. Det dyrkbare surrogatet Tulane-virus (TuV) ble inkludert i analyser av effekten av varme, UV bestråling og klor. Effekten på dyrkbarhet (infeksjonsevne) ble så sammenlignet med RT-qPCR metoder for å vurdere hvilken molekylær metode som gir det beste målet for virusreduksjon i cellekultur. Hvor godt molekylære metoder gjenspeilte cellekultur var avhengig av inaktiveringsmetode. Reduksjoner på grunn av termisk eksponering og kapsidskade ble best oppdaget hvis PMAxx eller RNase gikk foran RT-qPCR. UV-eksponering, som hovedsakelig fører til genomskader, ble bedre vurdert med en langdistanse-PCR. Åpenbart vil en pålitelig metode som fungerer like godt for alle inaktiveringsmetoder være utfordrende å designe. Et annet mål med dette prosjektet var å evaluere temperaturutviklingen i østersvev under ulike tilberedningsprosedyrer og å vurdere om disse temperaturene var tilstrekkelige for virusreduksjon. Østers ble tilsatt både NoV og TuV og utsatt for termiske behandlinger. Avhengig av behandling ble smittsom TuV redusert med 1,2 til 3,6 log10. Hvis virusmengden i østers minner om naturlige forurensningsnivåer som beskrevet av «European Food Safety Authority» og smittsom NoV reduseres på samme måte som TuV, vil de fleste av de valgte termiske behandlingene resultere i et produkt som er trygt for konsum. Våre RT-qPCR-resultater indikerer at NoV ble mindre påvirket av de termiske behandlingene enn TuV. Dette illustrerer behovet for en reproduserbar cellekulturanalyse for å korrekt evaluere reduksjoner i smittsom NoV. Det endelige målet med dette arbeidet fokuserte på modifikasjoner i depureringsprosessen som er en utbredt praksis for å fjerne potensielle patogener fra østers. Det ble undersøkt om klorering av forurensede østers eller en endring i depureringsvanntemperaturen påvirker reduksjonen av smittefarlig virus. For dette formålet ble TuV og/eller NoV bioakkumulert i stillehavsøsters. For å vurdere effekten av klorering ble forurensede østers plassert i sjøvann inneholdende 45 ppm klor i en time. Denne behandlingen hadde imidlertid ingen effekt på infeksjonsevnen til TuV. Flere faktorer kan forklare dette, inkludert tilstedeværelsen av organisk materiale, lokaliseringen av TuV i østersens fordøyelsesvev og den lave temperaturen på sjøvann som ble brukt til klorering (10°C). Å transportere en tilstrekkelig mengde av ethvert antiviralt middel inn i østersens fordøyelseskanal er utfordrende. Som et alternativ til klorering ble effekten av forhøyede vanntemperaturer under depurering evaluert. Kontaminerte østers ble plassert ved 12°C og 17°C og infektivitet og persistens av RNA ble overvåket i en måned. TuV RNA var mer persistent enn NoV RNA. TuV sank med ≤0,7 log10, mens NoV-reduksjoner var ~1,3 log10 ved slutten av depureringsperioden. Muligens reduseres NoV-binding ved samtidig bioakkumulering av begge virus, og sesongmessig ekspresjon av reseptorer i østersen forklare denne forskjellen. Infeksiøs TuV avtok jevnt og det var en signifikant forskjell mellom de to temperaturene. Dette var mest tydelig på dag 14 og 21 da reduksjoner ved 17°C var 1,3-1,7 log10 høyere enn ved 12°C. Etter fire uker ble ikke smittsom TuV påvist ved høyere temperatur, men kunne fortsatt påvises i lave nivåer i 12°C prøver. Lengden på depureringen hadde også innvirkning på reduksjonen i virus. Etter en uke var TuV-reduksjon 4,0 log10 etter fire uker. Dette innebærer at en utvidelse av depureringsperioden til mer enn én uke, muligens i kombinasjon med forhøyede vanntemperaturer, kan være fordelaktig for inaktivering og fjerning av viruspatogener. Samlet sett illustrerer de presenterte resultatene viktigheten av behandlingsstrategier etter høsting for å redusere risikoen for NoV-infeksjon. Disse strategiene er avgjørende for å motvirke NoV-infeksjoner knyttet til østerskonsum, da naturlig forurensning ikke lett kan unngås i det marine miljøet, spesielt nær strandlinjen. Følgelig er depurering og bruk av antivirale midler fortsatt av relevans.As one of the most common causes of gastroenteritis, norovirus (NoV) has been a burden on patients, health authorities and society worldwide. The pathogen is transferred through ingestion of infectious virus particles. Many food-borne NoV outbreaks have been linked to the consumption of raw shellfish, particularly oysters. NoV has been shown to bind to oyster digestive tissue via histo-blood group antigens, to sialic acid in gills and mantle, and can be found in oyster haemocytes. Thus, oysters readily accumulate NoV during filter feeding, and persistence of the virus during periods of depuration has been demonstrated. To ensure a safe product, methods to detect infectious NoV are needed. As NoV cannot be easily cultivated, RT-qPCR remains state of the art for NoV screening. Unfortunately, RNA from non-infectious virus is detected as well. The first objective of this work aimed at finding an effective molecular method to primarily detect infectious virus. To assess capsid damage, enzymatic (RNase) and viability dye (PMAxx) pre-treatments were applied. To better assess genome damage, long-range PCR analysis was utilised. The cultivable NoV surrogate Tulane virus (TuV) was exposed to inactivating conditions - heat, UV, and chlorine - to evaluate, which molecular method best approximated virus reductions in cell culture. How well molecular methods compared to cell culture depended on the inactivation mode. Reductions due to thermal exposure and capsid damage were best detected if pre-treatments preceded RT-qPCR. UV exposure, which mainly leads to genome damage, was better assessed with a long-range PCR. A reliable method that performs equally well for all modes of inactivation would be challenging to design. Another aim of this project was to evaluate temperature development in oyster tissue during various cooking procedures and to assess if these temperatures suffice for virus reduction to safe levels. Oysters were spiked with both NoV and TuV and subjected to thermal treatments. Depending on treatment, infectious TuV was reduced by 1.2 to 3.6 log10. If the virus load in oysters resembles natural contamination levels as described by the European Food Safety Authority and infectious NoV decreases in the same manner as TuV, most selected thermal treatments would result in a product safe for consumption. Our RT-qPCR results indicate that NoV was less affected by the thermal treatments than TuV. This illustrates the need for a reproducible cell culture assay to correctly evaluate reductions in infectious NoV. The final objective of this work focused on modifications in the depuration process, which is a widespread practice to remove potential pathogens from oysters. It was evaluated whether chlorination of contaminated oysters or a change in depuration water temperature influences the reduction in infectious virus. For this purpose, TuV and/or NoV were bioaccumulated in Pacific oysters. To assess the effect of chlorination, contaminated oysters were placed in sea water containing 45 ppm chlorine for one hour. However, this treatment did not have any effect on the infectivity of TuV. Several factors may account for this, including the presence of organic matter, the localisation of TuV in oyster digestive tissue and the low temperature of sea water used for chlorination (10°C). Transporting a sufficient amount of any antiviral agent into the oyster digestive tract is challenging. As an alternative to chlorination, the effect of elevated water temperatures during depuration was evaluated. Contaminated oysters were placed at 12°C and 17°C and virus infectivity and persistence of RNA were monitored over the course of one month. TuV RNA was more persistent than NoV. TuV decreased by ≤0.7 log10, while NoV reductions were ~1.3 log10 at the end of the depuration period. Possibly, reduced NoV binding during simultaneous bioaccumulation and the seasonal expression of receptors in the oyster may explain this difference. Infectious TuV decreased steadily and there was a significant difference between the two temperatures. This was most evident on days 14 and 21 when reductions at 17°C were 1.3-1.7 log10 higher than at 12°C. After four weeks, infectious TuV was not detected at the higher temperature but was still detectable at low levels in 12°C samples. The length of depuration also had an influence on the decrease in virus. TuV reductions increased from 4.0 log10 after four weeks. This implies an extension of the depuration period, possibly in combination with elevated water temperatures, may be beneficial for the inactivation and removal of viral pathogens. Overall, the presented results illustrate the importance of post-harvest processing strategies in mitigating the risk of NoV infection. These strategies are crucial in counteracting NoV infections linked to oyster consumption as natural contamination cannot easily be avoided in the marine environment, especially close to the shoreline. Accordingly, depuration and the use of antiviral agents remain of relevance.Doktorgradsavhandlin

Refining building energy modeling through aggregate analysis and probabilistic methods associated with occupant presence

textThe building sector represents the largest energy consumer among the United States' end use sectors. As a result, the public and private sector will continue to place great emphasis on designing energy efficient buildings that minimize operating costs while maintaining a healthy environment for its occupants. Creating design-phase building energy models can facilitate the process of selecting life-cycle appropriate design strategies aimed at maximizing building energy efficiency. The primary objective of this research study is to gain greater insight into likely causes of variation between energy predictions derived from building energy models and building energy performance during post-occupancy. Identifying sources of error can be used to improve future modeling efforts that can potentially lead to greater accuracy and better decisions made during the building's design phase. My research approach is to develop a method for conducting retrospective analysis of building energy models in the areas that affect the building's predicted and actual energy consumption. This entails collecting pre-construction and post-occupancy related data from various entities that exhibit influence on the building's energy performance. The method is then applied to recently-constructed military dormitory buildings that utilized building energy modeling and now have actual, metered building energy consumption data. The study also examines how building occupancy impacts energy performance. The value of this work will provide additional insight to future building energy modeling efforts.Civil, Architectural, and Environmental Engineerin

Complex RNA metabolism in the chloroplast: an update on the psbB operon

Expression of most plastid genes involves multiple post-transcriptional processing events, such as splicing, editing, and intercistronic processing. The latter involves the formation of mono-, di-, and multicistronic transcripts, which can further be regulated by differential stability and expression. The plastid pentacistronic psbB transcription unit has been well characterized in vascular plants. It encodes the subunits CP47 (psbB), T (psbT), and H (psbH) of photosystem II as well as cytochrome b(6) (petB) and subunit IV (petD) of the cytochrome b(6)f complex. Each of the petB and petD genes contains a group II intron, which is spliced during post-transcriptional modification. The small subunit of photosystem II, PsbN, is encoded in the intercistronic region between psbH and psbT but is transcribed in the opposite direction. Expression of the psbB gene cluster necessitates different processing events along with numerous newly evolved specificity factors conferring stability to many of the processed RNA transcripts, and thus exemplarily shows the complexity of RNA metabolism in the chloroplast

Reconstruction of Process Forces in a Five-Axis Milling Center with a LSTM Neural Network in Comparison to a Model-Based Approach

Based on the drive signals of a milling center, process forces can be reconstructed. Therefore, a novel approach is presented to reconstruct the process forces with a long short-term memory neural network (LSTM) using drive signals as an input. The LSTM is evaluated and compared to a model-based approach. The latter compensates nonlinearities and disturbances such as friction and inertia. For training of the LSTM, multiple milling processes are considered to enhance the generalizability. Training data is generated by recording drive signals and process forces measured by a dynamometer. The LSTM is then evaluated using a test set, which comprises new process parameters. It is shown that the LSTM has a lower root mean square error (RMSE) in comparison to the model-based approach. Especially, when changing the feed motion direction during milling, the neural network clearly outperforms the model-based approach. Nevertheless, there are processes, where the LSTM induced oscillations, which do not correspond to the measured forces. © 2020 MDPI Multidisciplinary Digital Publishing Institute. All rights reserved

Tool deflection compensation by drive signal-based force reconstruction and process control

Tool deflection is a major cause for shape deviations in milling. Therefore, an approach is presented to compensate tool deflection based on the drive signals of a milling center. First, a real-time capable model is implemented to reconstruct static process forces by using the drive signals of a machine tool. To calculate the actual deflection, the forces are combined with a stiffness model of the tool. Finally, a controller is designed to minimize shape deviation of the workpiece. Based on experimental milling investigations it is shown that tool deflection can be significantly reduced

Separable mechanisms underlying global feature-based attention

Feature-based attention is known to operate in a spatially global manner, in that the selection of attended features is not bound to the spatial focus of attention. Here we used electromagnetic recordings in human observers to characterize the spatiotemporal signature of such global selection of an orientation feature. Observers performed a simple orientation-discrimination task while ignoring task-irrelevant orientation probes outside the focus of attention. We observed that global feature-based selection, indexed by the brain response to unattended orientation probes, is composed of separable functional components. One such component reflects global selection based on the similarity of the probe with task-relevant orientation values ("template matching"), which is followed by a component reflecting selection based on the similarity of the probe with the orientation value under discrimination in the focus of attention ("discrimination matching"). Importantly, template matching occurs at similar to 150 ms after stimulus onset, similar to 80 ms before the onset of discrimination matching. Moreover, source activity underlying template matching and discrimination matching was found to originate from ventral extrastriate cortex, with the former being generated in more anterolateral and the latter in more posteromedial parts, suggesting template matching to occur in visual cortex higher up in the visual processing hierarchy than discrimination matching. We take these observations to indicate that the population-level signature of global feature-based selection reflects a sequence of hierarchically ordered operations in extrastriate visual cortex, in which the selection based on task relevance has temporal priority over the selection based on the sensory similarity between input representations