The role of history and strength of the oceanic forcing in sea level projections from Antarctica with the Parallel Ice Sheet Model

Mass loss from the Antarctic Ice Sheet constitutes the largest uncertainty in projections of future sea level rise. Ocean-driven melting underneath the floating ice shelves and subsequent acceleration of the inland ice streams are the major reasons for currently observed mass loss from Antarctica and are expected to become more important in the future. Here we show that for projections of future mass loss from the Antarctic Ice Sheet, it is essential (1) to better constrain the sensitivity of sub-shelf melt rates to ocean warming and (2) to include the historic trajectory of the ice sheet. In particular, we find that while the ice sheet response in simulations using the Parallel Ice Sheet Model is comparable to the median response of models in three Antarctic Ice Sheet Intercomparison projects – initMIP, LARMIP-2 and ISMIP6 – conducted with a range of ice sheet models, the projected 21st century sea level contribution differs significantly depending on these two factors. For the highest emission scenario RCP8.5, this leads to projected ice loss ranging from 1.4 to 4.0 cm of sea level equivalent in simulations in which ISMIP6 ocean forcing drives the PICO ocean box model where parameter tuning leads to a comparably low sub-shelf melt sensitivity and in which no surface forcing is applied. This is opposed to a likely range of 9.1 to 35.8 cm using the exact same initial setup, but emulated from the LARMIP-2 experiments with a higher melt sensitivity, even though both projects use forcing from climate models and melt rates are calibrated with previous oceanographic studies. Furthermore, using two initial states, one with a previous historic simulation from 1850 to 2014 and one starting from a steady state, we show that while differences between the ice sheet configurations in 2015 seem marginal at first sight, the historic simulation increases the susceptibility of the ice sheet to ocean warming, thereby increasing mass loss from 2015 to 2100 by 5 % to 50 %. Hindcasting past ice sheet changes with numerical models would thus provide valuable tools to better constrain projections. Our results emphasize that the uncertainty that arises from the forcing is of the same order of magnitude as the ice dynamic response for future sea level projections

The role of history and strength of the oceanic forcing in sea level projections from Antarctica with the Parallel Ice Sheet Model

Mass loss from the Antarctic Ice Sheet constitutes the largest uncertainty in projections of future sea level rise. Ocean-driven melting underneath the floating ice shelves and subsequent acceleration of the inland ice streams are the major reasons for currently observed mass loss from Antarctica and are expected to become more important in the future. Here we show that for projections of future mass loss from the Antarctic Ice Sheet, it is essential (1) to better constrain the sensitivity of sub-shelf melt rates to ocean warming and (2) to include the historic trajectory of the ice sheet. In particular, we find that while the ice sheet response in simulations using the Parallel Ice Sheet Model is comparable to the median response of models in three Antarctic Ice Sheet Intercomparison projects – initMIP, LARMIP-2 and ISMIP6 – conducted with a range of ice sheet models, the projected 21st century sea level contribution differs significantly depending on these two factors. For the highest emission scenario RCP8.5, this leads to projected ice loss ranging from 1.4 to 4.0 cm of sea level equivalent in simulations in which ISMIP6 ocean forcing drives the PICO ocean box model where parameter tuning leads to a comparably low sub-shelf melt sensitivity and in which no surface forcing is applied. This is opposed to a likely range of 9.1 to 35.8 cm using the exact same initial setup, but emulated from the LARMIP-2 experiments with a higher melt sensitivity, even though both projects use forcing from climate models and melt rates are calibrated with previous oceanographic studies. Furthermore, using two initial states, one with a previous historic simulation from 1850 to 2014 and one starting from a steady state, we show that while differences between the ice sheet configurations in 2015 seem marginal at first sight, the historic simulation increases the susceptibility of the ice sheet to ocean warming, thereby increasing mass loss from 2015 to 2100 by 5 % to 50 %. Hindcasting past ice sheet changes with numerical models would thus provide valuable tools to better constrain projections. Our results emphasize that the uncertainty that arises from the forcing is of the same order of magnitude as the ice dynamic response for future sea level projections

Drosophila neprilysins control insulin signaling and food intake via cleavage of regulatory peptides

Insulin and IGF signaling are critical to numerous developmental and physiological processes, with perturbations being pathognomonic of various diseases, including diabetes. Although the functional roles of the respective signaling pathways have been extensively studied, the control of insulin production and release is only partially understood. Herein, we show that in Drosophila expression of insulin-like peptides is regulated by neprilysin activity. Concomitant phenotypes of altered neprilysin expression included impaired food intake, reduced body size, and characteristic changes in the metabolite composition. Ectopic expression of a catalytically inactive mutant did not elicit any of the phenotypes, which confirms abnormal peptide hydrolysis as a causative factor. A screen for corresponding substrates of the neprilysin identified distinct peptides that regulate insulin-like peptide expression, feeding behavior, or both. The high functional conservation of neprilysins and their substrates renders the characterized principles applicable to numerous species, including higher eukaryotes and humans. DOI: http://dx.doi.org/10.7554/eLife.19430.00

Predation risk and the evolution of a vertebrate stress response: Parallel evolution of stress reactivity and sexual dimorphism

Predation risk is often invoked to explain variation in stress responses. Yet, the answers to several key questions remain elusive, including the following: (1) how predation risk influences the evolution of stress phenotypes, (2) the relative importance of environmental versus genetic factors in stress reactivity and (3) sexual dimorphism in stress physiology. To address these questions, we explored variation in stress reactivity (ventilation frequency) in a post-Pleistocene radiation of live-bearing fish, where Bahamas mosquitofish (Gambusia hubbsi) inhabit isolated blue holes that differ in predation risk. Individuals of populations coexisting with predators exhibited similar, relatively low stress reactivity as compared to low-predation populations. We suggest that this dampened stress reactivity has evolved to reduce energy expenditure in environments with frequent and intense stressors, such as piscivorous fish. Importantly, the magnitude of stress responses exhibited by fish from high-predation sites in the wild changed very little after two generations of laboratory rearing in the absence of predators. By comparison, low-predation populations exhibited greater among-population variation and larger changes subsequent to laboratory rearing. These low-predation populations appear to have evolved more dampened stress responses in blue holes with lower food availability. Moreover, females showed a lower ventilation frequency, and this sexual dimorphism was stronger in high-predation populations. This may reflect a greater premium placed on energy efficiency in live-bearing females, especially under high-predation risk where females show higher fecundities. Altogether, by demonstrating parallel adaptive divergence in stress reactivity, we highlight how energetic trade-offs may mould the evolution of the vertebrate stress response under varying predation risk and resource availability

MiFID II : Advisors’ view on the implementation and its consequences

Värdepappersmarknaden är en marknad under ständig utveckling. Den historiska utvecklingen som skett har skapat incitament för ett utökat regelverk för att stärka kundskyddet. På marknaden återfinns en rad olika aktörer som erbjuder rådgivning till privatpersoner, detta för att hjälpa kunderna investera på denna komplicerade marknad. För att stärka kundskyddet har Europeiska Unionen [EU] släppt ett direktiv vid namn MiFID II som verkar för att öka transparensen mellan rådgivare och kund och därmed ge kunden en ökad förståelse för olika investeringsalternativ. Medlemsländerna i EU hade fram till den 3 januari 2018 på sig att implementera direktivet i sin lagstiftning. Syftet med uppsatsen är därför att undersöka vilka effekter rådgivare tror att implementeringen av MiFID II har inneburit för konsumenter på värdepappersmarknaden. Syftet är även att öka förståelsen för hur MiFID II bidrar till transparens samt hur rådgivares dagliga arbete påverkas.  Vidare så har nio stycken semistrukturerade intervjuer genomförts för att uppnå studiens syfte. Studiens resultat påvisar att implementeringen av MiFID II har haft en positiv effekt för kunderna på marknaden. Den ökade transparensen har enligt respondenterna i studien resulterat i en ökad förståelse för de investeringar som kunderna genomför och har därmed minskat informationsasymmetrin på marknaden. Studien visar även att implementeringen hos de övriga aktörerna på marknaden har gått smidigare än hos de banker som deltagit i studien, detta då dessa redan innan implementeringen arbetat i linje med de nya reglerna. Implementeringen har dock inte påverkat längden på möten nämnvärt även om direktivet resulterat i en ökad tidsåtgång för rådgivare. Den ökade tidsåtgången tror respondenterna kan ha en negativ effekt för småsparare då en ökad arbetsbörda leder till att kostnaderna ökar. Studiens resultat tyder på att det i framtiden inte lönar sig för småsparare att besöka en rådgivare utan att de istället får förlita sig på andra alternativ som robotrådgivning.The securities market is under constant change. And the historical changes have created an incentive for an extended regulation in order to strengthen the customer protection. The securities market holds a number of different actors providing consulting service to individuals in order to help customers invest on this complicated market. In order to strengthen the customer protection and understanding, the European Union [EU] has released a directive called MiFID II that aims to increase the transparency between advisors and consumers. The deadline for the member states to implement the directive was January third 2018. The purpose of this study is to examine what effects the advisors believes the implementation of MiFID II have meant to the customers on the securities market. The intention is also to enhance the understanding of how MiFID II contributes to transparency as well as how it has affected the daily work of the advisors. Nine semi-structured interviews have been conducted in order to attain the purpose of the study. The study shows that the implementation of MiFID II has had a positive impact on the customers. The increased transparency has according to the respondents led to an increased understanding within the securities market, which has led to a decreased information asymmetry. The study also shows that the implementation was easier to accomplice for the other actors than for the banks. The other actors already worked in line with the new standards. The implementation has despite this not led to an increased duration of the meetings even though it has led to an additional workload for the advisors. The respondents find that the increased workload will lead to higher costs. The respondents believe that the increased workload have a negative effect for smaller savers. The results indicate that small savers will have to depend on other alternatives such as robot advisors in the future

Effektivisering av vareflyt rundt prosessen fellemontering i produksjonen på Madshus

Denne bacheloroppgaven er gjort i samarbeid med oppdragsgiver Madshus AS, Bjørn Myrhe gav oss tillit til å arbeide med frie hender. Formålet i denne oppgaven var å finne ut hvordan lean kunne brukes som et alternativ til automatisering rundt felleskiproduksjonen. Oppgaven er en casestudie hvor vi har benyttet oss av metodetriangulering for å besvare problemstillingen. Observasjoner, intervjuer og frekvensmålinger ble gjennomført i Madshus sine produksjonslokaler på Biri. Observasjonene ble gjort i form av en prosesskartlegging, etter det ble det gjennomført intervjuer med de ansatte som jobbet i de aktuelle prosessene. For å kvantifisere arbeidstiden ble det gjennomført frekvensmålinger på grunnlag av funnene fra prosesskartleggingen og intervjuene. En gjennomgang av relevant teori sammen med oppgavens resultater viser at lean ikke trenger å være et alternativ til automatisering, men heller kan bli brukt for å komplementere hverandre. Vi ser at Madshus kan gjøre store besparinger ved bruk av lean, men at man kan komme enda lenger med automatiseringer gjort på riktig måte – dog til en høyere investeringskostnad

Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations

Basal ice-shelf melting is the key driver of Antarctica's increasing sea-level contribution. In diminishing the buttressing force of the ice shelves that fringe the ice sheet, the melting increases the ice discharge into the ocean. Here we contrast the influence of basal melting in two different ice-shelf regions on the time-dependent response of an isothermal, inherently buttressed ice-sheet-shelf system. In the idealized numerical simulations, the basal-melt perturbations are applied close to the grounding line in the ice-shelf's (1) ice-stream region, where the ice shelf is fed by the fastest ice masses that stream through the upstream bed trough and (2) shear margins, where the ice flow is slower. The results show that melting below one or both of the shear margins can cause a decadal to centennial increase in ice discharge that is more than twice as large compared to a similar perturbation in the ice-stream region. We attribute this to the fact that melt-induced ice-shelf thinning in the central grounding-line region is attenuated very effectively by the fast flow of the central ice stream. In contrast, the much slower ice dynamics in the lateral shear margins of the ice shelf facilitate sustained ice-shelf thinning and thereby foster buttressing reduction. Regardless of the melt location, a higher melt concentration toward the grounding line generally goes along with a stronger response. Our results highlight the vulnerability of outlet glaciers to basal melting in stagnant, buttressing-relevant ice-shelf regions, a mechanism that may gain importance under future global warming

Development of Reference Buildings to Analyze the Potential for Energy-Efficient Refurbishment of Buildings

The building sector offers the largest potential for a significant reduction of greenhouse gas emissions. Based on own preliminary investigations for the State of Bavaria, a complete renovation of the building envelope of the current residential building stock would result in a reduced demand for final thermal energy for space heating and domestic hot water by about 70 %. The present study analyzes different existing reference buildings and reference methods. Based on a general literature review, specific criteria will be developed for reference models to represent the thermal energy consumption of the residential building stock for the regional domain under investigation. The objective is to represent the building stock with a limited amount of reference buildings. The method for the development of a reference building will be shown exemplarily for one category

Development of Reference Buildings to Analyze the Potential for Energy-Efficient Refurbishment of Buildings

The building sector offers the largest potential for a significant reduction of greenhouse gas emissions. Based on own preliminary investigations for the State of Bavaria, a complete renovation of the building envelope of the current residential building stock would result in a reduced demand for final thermal energy for space heating and domestic hot water by about 70 %. The present study analyzes different existing reference buildings and reference methods. Based on a general literature review, specific criteria will be developed for reference models to represent the thermal energy consumption of the residential building stock for the regional domain under investigation. The objective is to represent the building stock with a limited amount of reference buildings. The method for the development of a reference building will be shown exemplarily for one category

Whack-a-mole:En undersøgelse af falske nyheder og deres økosystemer

Vi argumenterer for, at falske nyheder skal forstås og undersøges empirisk i deres natur- lige habitat. Falske nyheder bør ikke blot håndteres som et spil whack-a-mole, hvor formålet er at slå det falske ned, hver gang det dukker op, som var det et muldvarpehoved i en spilleautomat, men derimod at forsøge at forstå de gange, muldvarpen graver