The evolution and storage of primitive melts in the Eastern Volcanic Zone of Iceland: the 10 ka Grímsvötn tephra series (i.e. the Saksunarvatn ash)

Major, trace and volatile elements were measured in a suite of primitive macrocrysts and melt inclusions from the thickest layer of the 10 ka Grímsvötn tephra series (i.e. Saksunarvatn ash) at Lake Hvítárvatn in central Iceland. In the absence of primitive tholeiitic eruptions (MgO > 7 wt.%) within the Eastern Volcanic Zone (EVZ) of Iceland, these crystal and inclusion compositions provide an important insight into magmatic processes in this volcanically productive region. Matrix glass compositions show strong similarities with glass compositions from the AD 1783–84 Laki eruption, confirming the affinity of the tephra series with the Grímsvötn volcanic system. Macrocrysts can be divided into a primitive assemblage of zoned macrocryst cores (An_78–An_92, Mg#_cpx = 82–87, Fo_79.5–Fo_87) and an evolved assemblage consisting of unzoned macrocrysts and the rims of zoned macrocrysts (An_60–An_68, Mg#_cpx = 71–78, Fo_70–Fo_76). Although the evolved assemblage is close to being in equilibrium with the matrix glass, trace element disequilibrium between primitive and evolved assemblages indicates that they were derived from different distributions of mantle melt compositions. Juxtaposition of disequilibrium assemblages probably occurred during disaggregation of incompatible trace element-depleted mushes (mean La/Yb_melt = 2.1) into aphyric and incompatible trace element-enriched liquids (La/Yb_melt = 3.6) shortly before the growth of the evolved macrocryst assemblage. Post-entrapment modification of plagioclase-hosted melt inclusions has been minimal and high-Mg# inclusions record differentiation and mixing of compositionally variable mantle melts that are amongst the most primitive liquids known from the EVZ. Coupled high field strength element (HFSE) depletion and incompatible trace element enrichment in a subset of primitive plagioclase-hosted melt inclusions can be accounted for by inclusion formation following plagioclase dissolution driven by interaction with plagioclase-undersaturated melts. Thermobarometric calculations indicate that final crystal-melt equilibration within the evolved assemblage occurred at ~1140°C and 0.0–1.5 kbar. Considering the large volume of the erupted tephra and textural evidence for rapid crystallisation of the evolved assemblage, 0.0–1.5 kbar is considered unlikely to represent a pressure of long-term magma accumulation and storage. Multiple thermometers indicate that the primitive assemblage crystallised at high temperatures of 1240–1300°C. Different barometers, however, return markedly different crystallisation depth estimates. Raw clinopyroxene-melt pressures of 5.5–7.5 kbar conflict with apparent melt inclusion entrapment pressures of 1.4 kbar. After applying a correction derived from published experimental data, clinopyroxene-melt equilibria return mid-crustal pressures of 4±1.5 kbar, which are consistent with pressures estimated from the major element content of primitive melt inclusions. Long-term storage of primitive magmas in the mid-crust implies that low CO_2 concentrations measured in primitive plagioclase-hosted inclusions (262–800 ppm) result from post-entrapment CO_2 loss during transport through the shallow crust. In order to reconstruct basaltic plumbing system geometries from petrological data with greater confidence, mineral-melt equilibrium models require refinement at pressures of magma storage in Iceland. Further basalt phase equilibria experiments are thus needed within the crucial 1–7 kbar range.D.A.N. was supported by a Natural Environment Research Council studentship (NE/1528277/1) at the start of this project. SIMS analyses were supported by Natural Environment Research Council Ion Microprobe Facility award (IMF508/1013).This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00410-015-1170-

Enuresis amongst schoolchildren in an Icelandic town

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenEnuresis is defined as uncontrolled voiding during day or night after normal control is expected. It is a common disorder, which can be divided into primary and secondary. We looked at the health files from children born between 1986-1988, written when they started school. There were 62 children which were said to have enuresis matched with 62 controls of same sex and from the same class. Questionnaires were sent to the parents of each child. That way five more children were found. A total of 101 took part in the study, 52 patients and 49 controls. The prevalence of enuresis was 9.8%, boys being almost two thirds. 69% had primary enuresis, 56% only/also at daytime. Over 44% of patients had a parent with history of enuresis and 48% other relatives too. 88% said that the disorder influenced their children's lives. Many parents worried and sought advice. Urinary infection was commoner among patients but not other diseases. Many children were evaluated and therapy attempted in 54%, mostly drugs and/or alarm device. Permanent results were disappointing. Our results are similar to other studies. Most of our patients still had enuresis when the study took place but 15-17% should spontaneously cure each year. A few still might have this problem in adulthood.Ósjálfráð þvaglát (enuresis) eru skilgreind sem þvagmissir að nóttu eða degi, eftir að börn hafa náð þeim aldri að þau eiga að hafa stjórn á þvaglátum. Þetta er nokkuð algengur kvilli sem ýmist hefur ávallt verið til staðar eða hætt um tíma og byrjað aftur. Tilgangur þessarar rannsóknar var að kanna tíðni kvillans meðal skólabarna á Akureyri, hugsanlega sjúkdóma sem að baki gætu legið og áhrif kvillans á líf barna og foreldra þeirra. Skoðaðar voru heilsufarsskrár barna í grunnskólum Akureyrar, sem fædd eru á árunum 1986-1988. Alls fundust 62 börn með þennan kvilla við upphaf skólagöngu. Til viðmiðunar voru fengin börn úr sama bekk og af sama kyni. Spurningalisti var sendur foreldrum og þannig fundust fimm börn til viðbótar. Alls tók 101 barn þátt í könnuninni, 52 sjúklingar og 49 börn í viðmiðunarhópi. Algengi reyndist 9,8%, drengir voru 64%. Alls höfðu 69% haft kvillann frá upphafi, 56% einnig eða eingöngu að degi til. Um 44% sjúklinga áttu foreldri með sögu um kvillann en alls 48% foreldra og/eða aðra ættingja. Þetta ástand var talið hafa haft áhrif á sálarlíf 88% barnanna. Margir foreldrar höfðu áhyggjur og leituðu ráða. Þvagfærasýking var algengari meðal sjúklinga, en ekki aðrir sjúkdómar. Mörg barnanna voru rannsökuð og meðferð reynd hjá 54%, aðallega lyf og/eða ýlutæki. Langtímaárangur var lélegur. Niðurstöður okkar eru sambærilegar við niðurstöður annarra rannsókna. Um 50% sjúklinganna misstu enn þvag er rannsóknin var gerð en talið er að 15-17% lagist sjálfkrafa á hverju ári. Kvillinn fylgir þó einstaka sjúklingum fram á fullorðinsár

Enuresis amongst schoolchildren in an Icelandic town

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenEnuresis is defined as uncontrolled voiding during day or night after normal control is expected. It is a common disorder, which can be divided into primary and secondary. We looked at the health files from children born between 1986-1988, written when they started school. There were 62 children which were said to have enuresis matched with 62 controls of same sex and from the same class. Questionnaires were sent to the parents of each child. That way five more children were found. A total of 101 took part in the study, 52 patients and 49 controls. The prevalence of enuresis was 9.8%, boys being almost two thirds. 69% had primary enuresis, 56% only/also at daytime. Over 44% of patients had a parent with history of enuresis and 48% other relatives too. 88% said that the disorder influenced their children's lives. Many parents worried and sought advice. Urinary infection was commoner among patients but not other diseases. Many children were evaluated and therapy attempted in 54%, mostly drugs and/or alarm device. Permanent results were disappointing. Our results are similar to other studies. Most of our patients still had enuresis when the study took place but 15-17% should spontaneously cure each year. A few still might have this problem in adulthood.Ósjálfráð þvaglát (enuresis) eru skilgreind sem þvagmissir að nóttu eða degi, eftir að börn hafa náð þeim aldri að þau eiga að hafa stjórn á þvaglátum. Þetta er nokkuð algengur kvilli sem ýmist hefur ávallt verið til staðar eða hætt um tíma og byrjað aftur. Tilgangur þessarar rannsóknar var að kanna tíðni kvillans meðal skólabarna á Akureyri, hugsanlega sjúkdóma sem að baki gætu legið og áhrif kvillans á líf barna og foreldra þeirra. Skoðaðar voru heilsufarsskrár barna í grunnskólum Akureyrar, sem fædd eru á árunum 1986-1988. Alls fundust 62 börn með þennan kvilla við upphaf skólagöngu. Til viðmiðunar voru fengin börn úr sama bekk og af sama kyni. Spurningalisti var sendur foreldrum og þannig fundust fimm börn til viðbótar. Alls tók 101 barn þátt í könnuninni, 52 sjúklingar og 49 börn í viðmiðunarhópi. Algengi reyndist 9,8%, drengir voru 64%. Alls höfðu 69% haft kvillann frá upphafi, 56% einnig eða eingöngu að degi til. Um 44% sjúklinga áttu foreldri með sögu um kvillann en alls 48% foreldra og/eða aðra ættingja. Þetta ástand var talið hafa haft áhrif á sálarlíf 88% barnanna. Margir foreldrar höfðu áhyggjur og leituðu ráða. Þvagfærasýking var algengari meðal sjúklinga, en ekki aðrir sjúkdómar. Mörg barnanna voru rannsökuð og meðferð reynd hjá 54%, aðallega lyf og/eða ýlutæki. Langtímaárangur var lélegur. Niðurstöður okkar eru sambærilegar við niðurstöður annarra rannsókna. Um 50% sjúklinganna misstu enn þvag er rannsóknin var gerð en talið er að 15-17% lagist sjálfkrafa á hverju ári. Kvillinn fylgir þó einstaka sjúklingum fram á fullorðinsár

Embracing the variety of sustainable business models: A prolific field of research and a future research agenda

Investigating the benefits of sustainable business models for our societies is an important and timely topic. This Special Volume contributes to current research by exploring a variety of sustainable models in use around the world. The accepted articles provide an overview of the various organizational forms, management mechanisms, sustainability solutions, challenges, theoretical lenses and empirical evidence, i.e. fundamental elements in the study of sustainable business models. In this introductory paper, the thirty-seven articles included in this Special Volume are presented, organized in four approaches to sustainable business models: 1/the generalist approach, 2/the technology-based approach, 3/the entrepreneurship and innovation approach and 4/the behavioral approach. In conclusion, avenues for future research are formulated, with a call for solid theory building, more sophisticated research methods, focus on the interplay of sustainable with existing conventional business models, and systemic consideration of the role of governments in advancing sustainable business models

Climatic control on Icelandic volcanic activity during the mid-Holocene: REPLY

We identify flaws in the criticisms of Harning et al. (2018)