Brief communication: PICOP, a new ocean melt parameterization under ice shelves combining PICO and a plume model

Basal melting at the bottom of Antarctic ice shelves is a major control on glacier dynamics, as it modulates the amount of buttressing that floating ice shelves exert onto the ice streams feeding them. Three-dimensional ocean circulation numerical models provide reliable estimates of basal melt rates but remain too computationally expensive for century-scale projections. Ice sheet modelers therefore routinely rely on simplified parameterizations based on either ice shelf depth or more sophisticated box models. However, existing parameterizations do not accurately resolve the complex spatial patterns of sub-shelf melt rates that have been observed over Antarctica's ice shelves, especially in the vicinity of the grounding line, where basal melting is one of the primary drivers of grounding line migration. In this study, we couple the Potsdam Ice-shelf Cavity mOdel (PICO, Reese et al., 2018) to a buoyant plume melt rate parameterization (Lazeroms et al., 2018) to create PICOP, a novel basal melt rate parameterization that is easy to implement in transient ice sheet numerical models and produces a melt rate field that is in excellent agreement with the spatial distribution and magnitude of observations for several ocean basins. We test PICOP on the Amundsen Sea sector of West Antarctica, Totten, and Moscow University ice shelves in East Antarctica and the Filchner-Ronne Ice Shelf and compare the results to PICO. We find that PICOP is able to reproduce inferred high melt rates beneath Pine Island, Thwaites, and Totten glaciers (on the order of 100&thinsp;m&thinsp;yr−1) and removes the “banding” pattern observed in melt rates produced by PICO over the Filchner-Ronne Ice Shelf. PICOP resolves many of the issues contemporary basal melt rate parameterizations face and is therefore a valuable tool for those looking to make future projections of Antarctic glaciers.</p

Influence of reaction atmosphere (H2O, N2, H2, CO2, CO) on fluidized-bed fast pyrolysis of biomass using detailed tar vapor chemistry in computational fluid dynamics

Secondary pyrolysis in fluidized bed fast pyrolysis of biomass is the focus of this work. A novel computational fluid dynamics (CFD) model coupled with a comprehensive chemistry scheme (134 species and 4169 reactions, in CHEMKIN format) has been developed to investigate this complex phenomenon. Previous results from a transient three-dimensional model of primary pyrolysis were used for the source terms of primary products in this model. A parametric study of reaction atmospheres (H2O, N2, H2, CO2, CO) has been performed. For the N2 and H2O atmosphere, results of the model compared favorably to experimentally obtained yields after the temperature was adjusted to a value higher than that used in experiments. One notable deviation versus experiments is pyrolytic water yield and yield of higher hydrocarbons. The model suggests a not overly strong impact of the reaction atmosphere. However, both chemical and physical effects were observed. Most notably, effects could be seen on the yield of various compounds, temperature profile throughout the reactor system, residence time, radical concentration, and turbulent intensity. At the investigated temperature (873 K), turbulent intensity appeared to have the strongest influence on liquid yield. With the aid of acceleration techniques, most importantly dimension reduction, chemistry agglomeration, and in-situ tabulation, a converged solution could be obtained within a reasonable time (∼30 h). As such, a new potentially useful method has been suggested for numerical analysis of fast pyrolysis

KEMIRINGAN LERENG DAN GRANULOMETRI SEDIMEN GISIK TANJUNG MERAH, BITUNG SULAWESI UTARA

Beach slope and sediment granulometry  is one of the importat aspect in coastal management.  Beach offers a variety of functions and potential to be utilized. In the interests of phisical use in the beach, coastal structure in the form of groynes has been built. Actually, the groin has been used as a dock. This research was conducted with the aim of revealing the slope and granulometry sediment in Tanjung Merah beach. The results obtained, the beach slope is considered sloping and very sloping, the composition of the sediment consists mainly  of medium sand, fine sand and very fine sand. Sediment distribution analysis obtained results, the main grain size was mainly in the form of medium sand, sorting was mainly classified as poor, skewness was mostly asymmetrie strong to large size, most curtosis was mesokurtic. The results of the study indicate the occurrence of the process of erosion and deposition ia certain spaces on the beach studied.Keywords: Tanjung Merah, beach slope, sediment granulometryKemiringan lereng dan granulometri sedimen gisik merupakan salah satu aspek penting dalam pengelolaan pantai. Gisik menawarkan beragam fungsi dan potensi untuk dimanfaatkan. Dalam kepentingan pemanfaatan lahan gisik, berbagai modifikasi dilakukan oleh manusia. Pada gisik di Tanjung Merah, telah dibangun struktur pantai berupa groin. Secara aktual, groin tersebut telah difunsikan sebagai dermaga. Penelitian ini dilakukan dengan tujuan mengungkapkan kemiringan dan granulometri sedimen di gisik Tanjung Merah. Hasil penelitian yang diperoleh, lereng gisik terkriteria miring dan sangat miring, komposisi sedimen terutama terdiri dari pasir sedang, pasir halus, dan pasir sangat halus. Analisis distribusi memperoleh hasil, rataan empirik terutama berupa pasir sedang, penyortiran terutama terklasifikasi buruk, kemencengan terbanyak berupa asimetris kuat ke ukuran besar, peruncingan terbanyak berupa mesokurtik. Hasil studi mengindikasikan terjadi proses erosi dan deposisi pada ruang-ruang tertentu di gisik yang ditelaah.Kata kunci : Tanjung Merah, kemiringan lereng, granulometri sedime

Secondary flow in contour currents controls the formation of moat-drift contourite systems

Ocean currents control seafloor morphology and the transport of sediments, organic carbon, nutrients, and pollutants in deep-water environments. A better connection between sedimentary deposits formed by bottom currents (contourites) and hydrodynamics is necessary to improve reconstructions of paleocurrent and sediment transport pathways. Here we use physical modeling in a three-dimensional flume tank to analyse the morphology and hydrodynamics of a self-emerging contourite system. The sedimentary features that developed on a flat surface parallel to a slope are an elongated depression (moat) and an associated sediment accumulation (drift). The moat-drift system can only form in the presence of a secondary flow near the seafloor that transports sediment from the slope toward the drift. The secondary flow increases with higher speeds and steeper slopes, leading to steeper adjacent drifts. This study shows how bottom currents shape the morphology of the moat-drift system and highlights their potential to estimate paleo-ocean current strength

Anhedonia is associated with poor health status and more somatic and cognitive symptoms in patients with coronary artery disease

Purpose: The effectiveness of cardiac rehabilitation (CR) in patients with coronary artery disease (CAD) is moderated by negative emotions and clinical factors, but no studies evaluated the role of positive emotions. This study examined whether anhedonia (i.e. the lack of positive affect) moderated the effectiveness of CR on health status and somatic and cognitive symptoms. Methods: CAD patients (n = 368) filled out the Hospital Anxiety and Depression Scale (HADS) to assess anhedonia at the start of CR, and the Short-Form Health Survey (SF-36) and the Health Complaints Scale (HCS) at the start of CR and at 3 months to assess health status and somatic and cognitive symptoms, respectively. Results: Adjusting for clinical and demographic factors, health status improved significantly during the follow-up (F(1,357) = 10.84, P = .001). Anhedonic patients reported poorer health status compared with non-anhedoni

Re-annotation of the Theileria parva genome refines 53% of the proteome and uncovers essential components of N-glycosylation, a conserved pathway in many organisms

The apicomplexan parasite Theileria parva causes a livestock disease called East coast fever (ECF), with millions of animals at risk in sub-Saharan East and Southern Africa, the geographic distribution of T. parva. Over a million bovines die each year of ECF, with a tremendous economic burden to pastoralists in endemic countries. Comprehensive, accurate parasite genome annotation can facilitate the discovery of novel chemotherapeutic targets for disease treatment, as well as elucidate the biology of the parasite. However, genome annotation remains a significant challenge because of limitations in the quality and quantity of the data being used to inform the location and function of protein-coding genes and, when RNA data are used, the underlying biological complexity of the processes involved in gene expression. Here, we apply our recently published RNAseq dataset derived from the schizont life-cycle stage of T. parva to update structural and functional gene annotations across the entire nuclear genome.; The re-annotation effort lead to evidence-supported updates in over half of all protein-coding sequence (CDS) predictions, including exon changes, gene merges and gene splitting, an increase in average CDS length of approximately 50 base pairs, and the identification of 128 new genes. Among the new genes identified were those involved in N-glycosylation, a process previously thought not to exist in this organism and a potentially new chemotherapeutic target pathway for treating ECF. Alternatively-spliced genes were identified, and antisense and multi-gene family transcription were extensively characterized.; The process of re-annotation led to novel insights into the organization and expression profiles of protein-coding sequences in this parasite, and uncovered a minimal N-glycosylation pathway that changes our current understanding of the evolution of this post-translational modification in apicomplexan parasites

The impact of emotional well-being on long-term recovery and survival in physical illness: a meta-analysis

This meta-analysis synthesized studies on emotional well-being as predictor of the prognosis of physical illness, while in addition evaluating the impact of putative moderators, namely constructs of well-being, health-related outcome, year of publication, follow-up time and methodological quality of the included studies. The search in reference lists and electronic databases (Medline and PsycInfo) identified 17 eligible studies examining the impact of general well-being, positive affect and life satisfaction on recovery and survival in physically ill patients. Meta-analytically combining these studies revealed a Likelihood Ratio of 1.14, indicating a small but significant effect. Higher levels of emotional well-being are beneficial for recovery and survival in physically ill patients. The findings show that emotional well-being predicts long-term prognosis of physical illness. This suggests that enhancement of emotional well-being may improve the prognosis of physical illness, which should be investigated by future research