Revisiting Hele-Shaw dynamics to better understand beach evolution

Wave action, particularly during storms, drives the evo lution of beaches. Beach evolution by non-linear break ing waves is poorly understood due to its three-dimensional character, the range of scales involved, and our limited understanding of particle-wave interactions. We show how a novel, three-phase extension to the classic “Hele-Shaw” laboratory experiment can be designed that creates beach morphologies with breaking waves in a quasi-two-dimensional setting. Our thin Hele-Shaw cell simplifies the inherent complexity of three-phase dynamics: all dynamics become clearly visible and measurable. We show that beaches can be created in tens of minutes by several types of breaking waves, with about one-second periods. Quasi-steady beach morphologies emerge as function of initial water depth, at-rest bed level and wave-maker frequency. These are classified mathematically and lead to beaches, berms and sand bars

ELM divertor peak energy fluence scaling to ITER with data from JET, MAST and ASDEX upgrade

A newly established scaling of the ELM energy fluence using dedicated data sets from JET operation with CFC & ILW plasma facing components (PFCs), ASDEX Upgrade (AUG) operation with both CFC and full-W PFCs and MAST with CFC walls has been generated. The scaling reveals an approximately linear depen- dence of the peak ELM energy with the pedestal top electron pressure and with the minor radius; a square root dependence is seen on the relative ELM loss energy. The result of this scaling gives a range in parallel peak ELM energy fluence of 10–30 MJm −2 for ITER Q = 10 operation and 2.5–7.5 MJm −2 for in- termediate ITER operation at 7.5 MA and 2.65 T. These latter numbers are calculated using a numerical regression ( ε II = 0 . 28 MJ m 2 n 0 . 75 e T 1 e E 0 . 5 ELM R 1 geo ). A simple model for ELM induced thermal load is introduced, resulting in an expression for the ELM energy fluence of ε II ∼= 6 πp e R geo q edge . The relative ELM loss energy in the data is between 2–10% and the ELM energy fluence varies within a range of 10 0.5 ∼3 con- sistently for each individual device. The so far analysed power load database for ELM mitigation experi- ments from JET-EFCC and Kicks, MAST-RMP and AUG-RMP operation are found to be consistent with both the scaling and the introduced model, ie not showing a further reduction with respect to their pedestal pressure. The extrapolated ELM energy fluencies are compared to material limits in ITER and found to be of concern.RCUK Energy Programme P012450/1EURATOM 63305

Evidence of functional cell-mediated immune responses to nontypeable Haemophilus influenzae in otitis-prone children

Otitis media (OM) remains a common paediatric disease, despite advances in vaccinology. Susceptibility to recurrent acute OM (rAOM) has been postulated to involve defective cell-mediated immune responses to common otopathogenic bacteria. We compared the composition of peripheral blood mononuclear cells (PBMC) from 20 children with a history of rAOM (otitis-prone) and 20 healthy non-otitis-prone controls, and assessed innate and cell-mediated immune responses to the major otopathogen nontypeable Haemophilus influenzae (NTHi). NTHi was a potent stimulator of inflammatory cytokine secretion from PBMC within 4 hours, with no difference in cytokine levels produced between PBMC from cases or controls. In the absence of antigen stimulation, otitis-prone children had more circulating Natural Killer (NK) cells (p<0.01), particularly NKdim (CD56lo) cells (p<0.01), but fewer CD4+ T cells (p<0.01) than healthy controls. NTHi challenge significantly increased the proportion of activated (CD107a+) NK cells in otitis-prone and non-otitis-prone children (p<0.01), suggesting that NK cells from otitis-prone children are functional and respond to NTHi. CD8+ T cells and NK cells from both cases and controls produced IFNγ in response to polyclonal stimulus (Staphylococcal enterotoxin B; SEB), with more IFNγ+ CD8+ T cells present in cases than controls (p<0.05) but similar proportions of IFNγ+ NK cells. Otitis-prone children had more circulating IFNγ-producing NK cells (p<0.05) and more IFNγ-producing CD4+ (p<0.01) or CD8+ T-cells (p<0.05) than healthy controls. In response to SEB, more CD107a-expressing CD8+ T cells were present in cases than controls (p<0.01). Despite differences in PBMC composition, PBMC from otitis-prone children mounted innate and T cell-mediated responses to NTHi challenge that were comparable to healthy children. These data provide evidence that otitis-prone children do not have impaired functional cell mediated immunity

Biogeochemical processes in the active layer and permafrost of a high Arctic fjord valley

Warming of ground is causing microbial decomposition of previously frozen sedimentary organic carbon in Arctic permafrost. However, the heterogeneity of the permafrost landscape and its hydrological processes result in different biogeochemical processes across relatively small scales, with implications for predicting the timing and magnitude of permafrost carbon emissions. The biogeochemical processes of iron- and sulfate-reduction produce carbon dioxide and suppress methanogenesis. Hence, in this study, the biogeochemical processes occurring in the active layer and permafrost of a high Arctic fjord valley in Svalbard are identified from the geochemical and stable isotope analysis of aqueous and particulate fractions in sediment cores collected from ice-wedge polygons with contrasting water content. In the drier polygons, only a small concentration of organic carbon (<5.40 dry weight%) has accumulated. Sediment cores from these drier polygons have aqueous and solid phase chemistries that imply sulfide oxidation coupled to carbonate and silicate dissolution, leading to high concentrations of aqueous iron and sulfate in the pore water profiles. These results are corroborated by δ34S and δ18O values of sulfate in active layer pore waters, which indicate the oxidative weathering of sedimentary pyrite utilising either oxygen or ferric iron as oxidising agents. Conversely, in the sediments of the consistently water-saturated polygons, which contain a high content of organic carbon (up to 45 dry weight%), the formation of pyrite and siderite occurred via the reduction of iron and sulfate. δ34S and δ18O values of sulfate in active layer pore waters from these water-saturated polygons display a strong positive correlation (R2 = 0.98), supporting the importance of sulfate reduction in removing sulfate from the pore water. The significant contrast in the dominant biogeochemical processes between the water-saturated and drier polygons indicates that small-scale hydrological variability between polygons induces large differences in the concentration of organic carbon and in the cycling of iron and sulfur, with ramifications for the decomposition pathway of organic carbon in permafrost environments

Validation of screening questions and symptom coherence of night eating in the Swedish Twin Registry

Background Screening criteria have been used to estimate the prevalence of night eating syndrome (NES), but no validation studies have been conducted. Method We examined the validity of two screening questions for NES using a structured interview with adults enrolled in the Swedish Twin Study of Adults: Genes and Environment (STAGE) study. We also examined the coherence of the proposed diagnostic criteria for NES. A total of 416 participants (men = 179; women = 237) completed the interview and reported complete data for study inclusion. Results The following values were calculated for the screening items after confirmation by interview for men and women, respectively: Positive predictive value =.66 and.67, negative predictive value =.52 and.45, sensitivity =.62 and.63, and specificity =.56 and.50. As increasingly stringent diagnostic criteria were applied to the sample, prevalence of NES dropped. Nocturnal ingestions were more likely to co-occur with other NES symptoms than evening hyperphagia, which occurred frequently, but often in isolation; women were more likely to report a co-occurrence of symptoms than men, who were not likely to report distress related to NES symptoms. Conclusion In sum, almost two-thirds of participants were correctly identified as having NES (without considering distress or impairment) if they answered positively on the screening questions, and about half of the participants were correctly identified as not having NES when answering negatively on the screening questions. Although self-report questions are somewhat informative, a structured interview remains the gold standard for diagnosing NES

The role of plasma-atom and molecule interactions on power \& particle balance during detachment on the MAST Upgrade Super-X divertor

First quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor show an unprecedented impact of plasma-molecular interactions involving molecular ions (likely $D_2^+$), resulting in strong ion sinks, leading to a reduction of ion target flux. This starts to occur as the ionisation source detaches from the target, leading to a build-up of molecules below the ionisation source who get excited, resulting in Molecular Activated Recombination (MAR) and Dissociation (MAD). The particle sinks in the divertor chamber exceed the ion sources in the middle of the detached operational regime before electron-ion recombination (EIR) starts to occur, demonstrating the strong capabilities for particle exhaust in the Super-X Configuration. MAD is the dominant volumetric neutral atom creation mechanism and results in significant power losses. This, combined with electron-impact excitation preceding ionisation, are the dominant power loss mechanisms in the divertor chamber. As the plasma becomes more deeply detached, EIR starts to occur and electron temperatures below 0.2 eV are achieved. Even at such low electron temperature conditions, MAR is observed to be an important ion sink mechanism, which suggests the presence of highly vibrationally excited molecules in the cold detached regime. The total radiative power loss is consistent with extrapolations of spectroscopic inferences to hydrogenic radiative power losses, which suggests that intrinsic impurity radiation, despite the carbon walls, is minor. These observations are observed in Ohmic L-mode, ELM-free H-mode and type I ELMy H-mode discharges

Genetic and environmental aspects in the association between attention-deficit hyperactivity disorder symptoms and binge-eating behavior in adults: A twin study

Background Prior research demonstrated that attention-deficit hyperactivity disorder (ADHD) is associated with binge-eating behavior, binge-eating disorder (BED), and bulimia nervosa (BN). The aim of this study was to investigate these associations in an adult twin population, and to determine the extent to which ADHD symptoms and binge-eating behavior share genetic and environmental factors. Methods We used self-reports of current ADHD symptoms and lifetime binge-eating behavior and associated characteristics from a sample of over 18 000 adult twins aged 20-46 years, from the population-based Swedish Twin Registry. Mixed-effects logistic regression was used to examine the association between ADHD and lifetime binge-eating behavior, BED, and BN. Structural equation modeling was used in 13 773 female twins to determine the relative contribution of genetic and environmental factors to the association between ADHD symptoms and binge-eating behavior in female adult twins. Results ADHD symptoms were significantly associated with lifetime binge-eating behavior, BED, and BN. The heritability estimate for current ADHD symptoms was 0.42 [95% confidence interval (CI) 0.41-0.44], and for lifetime binge-eating behavior 0.65 (95% CI 0.54-0.74). The genetic correlation was estimated as 0.35 (95% CI 0.25-0.46) and the covariance between ADHD and binge-eating behavior was primarily explained by genetic factors (91%). Non-shared environmental factors explained the remaining part of the covariance. Conclusions The association between adult ADHD symptoms and binge-eating behavior in females is largely explained by shared genetic risk factors

Variability in oxidative degradation of charcoal: influence of production variables and environmental exposure

&lt;p&gt;Charcoal is a key component of the Black Carbon (BC) continuum, where BC is characterized as a recalcitrant, fire-derived, polyaromatic material. Charcoal is an important source of palaeoenvironmental data, and of great interest as a potential carbon sink, due to its high apparent environmental stability. However, at least some forms of charcoal are clearly susceptible to environmental alteration and degradation over relatively short timescales. Although these processes have importance for the role of charcoal in global biogeochemistry, they remain poorly understood.&lt;/p&gt; &lt;p&gt;Here we present results of an investigation into the susceptibility of a range of charcoal samples to oxidative degradation in acidified potassium dichromate. The study examines both freshly-produced charcoal, and charcoal exposed to environmental conditions for up to 50,000 years. We compare the proportion of carbon present in different forms between the samples, specifically with respect to the relative chemical resistance of these forms. This was undertaken in order to improve understanding of the post-depositional diagenetic changes affecting charcoal within environmental deposits.&lt;/p&gt; &lt;p&gt;A wide range in chemical compositions are apparent both within and between the sample groups. In freshly-produced charcoal, material produced at 300 °C contains carbon with more labile forms than charcoal produced at &#x2265;400 °C, signifying a key chemical change over the 300–400 °C temperature range. Charcoal exposed to environmental depositional conditions is frequently composed of a highly carboxylated aromatic structure and contains a range of carbon fractions of varying oxidative resistance. These findings suggest that a significant number of the environmental charcoals have undergone post-depositional diagenetic alteration. Further, the data highlight the potential for the use of controlled progressive oxidative degradation as a method to characterize chemical differences between individual charcoal samples.&lt;/p&gt

Determining the temporal profile of intracranial pressure changes following transient stroke in an ovine model

Cerebral edema and elevated intracranial pressure (ICP) are the leading cause of death in the first week following stroke. Despite this, current treatments are limited and fail to address the underlying mechanisms of swelling, highlighting the need for targeted treatments. When screening promising novel agents, it is essential to use clinically relevant large animal models to increase the likelihood of successful clinical translation. As such, we sought to develop a survival model of transient middle cerebral artery occlusion (tMCAO) in the sheep and subsequently characterize the temporal profile of cerebral edema and elevated ICP following stroke in this novel, clinically relevant model. Merino-sheep (27M;31F) were anesthetized and subject to 2 h tMCAO with reperfusion or sham surgery. Following surgery, animals were allowed to recover and returned to their home pens. At preselected times points ranging from 1 to 7 days post-stroke, animals were re-anesthetized, ICP measured for 4 h, followed by imaging with MRI to determine cerebral edema, midline shift and infarct volume (FLAIR, T2 and DWI). Animals were subsequently euthanized and their brain removed for immunohistochemical analysis. Serum and cerebrospinal fluid samples were also collected and analyzed for substance P (SP) using ELISA. Intracranial pressure and MRI scans were normal in sham animals. Following stroke, ICP rose gradually over time and by 5 days was significantly (p < 0.0001) elevated above sham levels. Profound cerebral edema was observed as early as 2 days post-stroke and continued to evolve out to 6 days, resulting in significant midline shift which was most prominent at 5 days post-stroke (p < 0.01), in keeping with increasing ICP. Serum SP levels were significantly elevated (p < 0.01) by 7 days post-tMCAO. We have successfully developed a survival model of ovine tMCAO and characterized the temporal profile of ICP. Peak ICP elevation, cerebral edema and midline shift occurred at days 5-6 following stroke, accompanied by an elevation in serum SP. Our findings suggest that novel therapeutic agents screened in this model targeting cerebral edema and elevated ICP would most likely be effective when administered prior to 5 days, or as early as possible following stroke onset.Annabel J. Sorby-Adams, Anna V. Leonard, Levi E. Elms, Oana C. Marian, Jan W. Hoving, Nawaf Yassi, Robert Vink, Emma Thornton and Renée J. Turne