The consistency between the severity of dental caries among 12- and 15-year old children (DMFT/S) and caries in key teeth

Efst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinnTilgangur: Markmið rannsóknarinnar var að skoða staðsetningu og dreifingu tannátu og kanna hvort hægt sé að benda á lykiltennur eða fleti tanna við mat á tannátu hjá 12 og 15 ára börnum í gögnum MUNNÍS (VSN 03-140) 2005. Efniviður og aðferðir: Gögn um tannátu hjá 12 og 15 ára börnum sem skoðuð voru í MUNNÍS (VSN 03-140) 2005 voru greind til að meta dreifingu á tannátu og til að finna hvort hægt væri að benda á lykiltennur til greiningar á tannátu hjá börnum. Upplýsingar um 1.388 börn voru skoðaðar. Notuð var núll þanin Poisson aðhvarfsgreining, hlutfall rétt flokkað, Cohen´s Kappa og næmi og sértæki til að meta gögnin. Niðurstöður: Sex ára jaxlar höfðu oftast fyllingu eða tannátu sem náði inn í tannbein hjá bæði 12 og 15 ára börnum. Ef litið var til framtanna í efri gómi voru hliðarframtennur með mest af byrjandi tannátu í glerungi hjá báðum aldurshópum. Framtennur neðri góms voru með minnst af fyllingum og tannátu hjá þessum aldurshópum. Hjá bæði 12 og 15 ára börnunum voru 12 ára jaxlar næst á eftir sex ára jöxlum hvað varðar fjölda fyllinga og tannátu sem náði inn í tannbein. Þegar fjórir til átta jaxlar voru skoðaðir sjónrænt og bornir saman við bestu skoðun (samsett sjónræn skoðun og röntgenskoðun) var næmi þess 69-77, hlutfall rétt flokkað 0,737-0,839 og Kappa 0,53-0,63. Skimun á öllum tönnum gaf næmið 78,8, hlutfall rétt flokkað 0,841 og Kappa 0,65 samanborið við bestu skoðun í gögnum MUNNÍS en 38,7% þeirra sem voru greind án tannátu með sjónrænni skimun allra tanna voru í raun með tannátu við bestu skoðun. Ályktun: Gæði skimunar allra tanna með sjónrænni skoðun eru ekki góð og gefur ekki rétta mynd af tannheilsu einstaklingsins þannig að ekki er réttlætanlegt að benda á ákveðnar lykiltennur fyrir slíka skimun.Introduction: The objective of this research was to analyse the location and distribution of dental caries to determine ig it would be possible to find key teeth or tooth surfaces in the assessment of dental caries in 12- and 15-year old children from the MUNNIS data (VSN 03-140) in 2005. Materials and methods: Data on dental caries in 12- and 15-year old children surveyed in MUNNIS (VSN 03-140) in 2005 were analysed (N=1.388 children) to see the distribution of dental caries and to analyse if it would be possible to find key teeth for the diagnosis of dental caries in children. Zero Inflated Poisson Regression, Agreement, Cohen´s Kappa and Sensitivity and Specificity were used to analyse the data. Results: First molars were most often affected by dental caries in both 12- and 15-year old children. Looking at the front teeth in the upper jaw, lateral incisors were those most at risk for dental caries in both age groups. Canines and incisors in the lower jaw were the least affected teeth in these age groups. In both 12-year old and 15-year old children, second molars were next to first molars when scoring the teeth most affected by dental caries. When four to eight molars were examined visually and compared with combined visual and X-ray examination then the sensitivity was 69-77, Agreement 0.737-0.839 and Kappa 0.53-0.63. Screening all teeth gave sensitivity of 78.8, Agreement of 0.841 and Kappa of 0.65 compared with combined visual and X-ray examination in MUNNIS data and 38.7% of those diagnosed without caries did in fact have caries. Conclusion: The quality of screening all teeth by visual examination is not good enough to allow one to point out certain key teeth for such screening and the screening do not give an accurate picture of the individuals dental health

Rhyolitic tephra horizons in northwestern Europe and Iceland from the AD 700s-800s: a potential alternative for dating first human impact

The distribution and geochemistry of four rhyolitic tephra horizons from Iceland dated to the ad 700s–800s is assessed. These include the rhyolitic phase of the Landnám tephra (ad 870s), the ad 860 layer, a previously unrecorded tephra called the GA4–85 layer (c. ad 700–800) and the Tjïrnuvík tephra (c. ad 800s). The ad 860 and GA4–85 layers were first found in peat bogs in north Ireland. They are here correlated with equivalent horizons on Iceland which were found below the Landnám tephra (c. ad 870s). This time period is considered important in the North Atlantic region, because it coincides with a phase of human settlement in Iceland and the Faroe Islands. The establishment of a detailed tephrochronology may provide a tool for exact dating of sediment successions and sediments associated with archaeological excavations. Caution must be taken especially on Iceland where the Landnám tephra is often used for dating archaeological sites. This investigation show that several rhyolitic tephra horizons occur close in time to the Landnám tephra, and that mistakes can be made if detailed geochemical analyses are not carried out, especially in areas which are distal to the source of the Landnám tephra (the Veidivötn and Torfajökull volcanic systems, southern Iceland)

Using dissolved H₂O in rhyolitic glasses to estimate palaeo-ice thickness during a subglacial eruption at Bláhnúkur(Torfajökull, Iceland)

The last decade has seen the refinement of a technique for reconstructing palaeo-ice thicknesses based on using the retained H2O and CO2 content in glassy eruptive deposits to infer quenching pressures and therefore ice thicknesses. The method is here applied to Bláhnúkur, a subglacially erupted rhyolitic edifice in Iceland. A decrease in water content from ~0.7 wt.% at the base to ~0.3 wt.% at the top of the edifice suggests that the ice was 400 m thick at the time of the eruption. As Bláhnúkur rises 350 m above the surrounding terrain, this implies that the eruption occurred entirely within ice, which corroborates evidence obtained from earlier lithofacies studies. This paper presents the largest data set (40 samples) so far obtained for the retained volatile contents of deposits from a subglacial eruption. An important consequence is that it enables subtle but significant variations in water content to become evident. In particular, there are anomalous samples which are either water-rich (up to 1 wt.%) or water-poor (~0.2 wt.%), with the former being interpreted as forming intrusively within hyaloclastite and the latter representing batches of magma that were volatile-poor prior to eruption. The large data set also provides further insights into the strengths and weaknesses of using volatiles to infer palaeo-ice thicknesses and highlights many of the uncertainties involved. By using examples from Bláhnúkur, the quantitative use of this technique is evaluated. However, the relative pressure conditions which have shed light on Bláhnúkur’s eruption mechanisms and syn-eruptive glacier response show that, despite uncertainties in absolute values, the volatile approach can provide useful insight into the mechanisms of subglacial rhyolitic eruptions, which have never been observed

The consistency between the severity of dental caries among 12- and 15-year old children (DMFT/S) and caries in key teeth

Efst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinnTilgangur: Markmið rannsóknarinnar var að skoða staðsetningu og dreifingu tannátu og kanna hvort hægt sé að benda á lykiltennur eða fleti tanna við mat á tannátu hjá 12 og 15 ára börnum í gögnum MUNNÍS (VSN 03-140) 2005. Efniviður og aðferðir: Gögn um tannátu hjá 12 og 15 ára börnum sem skoðuð voru í MUNNÍS (VSN 03-140) 2005 voru greind til að meta dreifingu á tannátu og til að finna hvort hægt væri að benda á lykiltennur til greiningar á tannátu hjá börnum. Upplýsingar um 1.388 börn voru skoðaðar. Notuð var núll þanin Poisson aðhvarfsgreining, hlutfall rétt flokkað, Cohen´s Kappa og næmi og sértæki til að meta gögnin. Niðurstöður: Sex ára jaxlar höfðu oftast fyllingu eða tannátu sem náði inn í tannbein hjá bæði 12 og 15 ára börnum. Ef litið var til framtanna í efri gómi voru hliðarframtennur með mest af byrjandi tannátu í glerungi hjá báðum aldurshópum. Framtennur neðri góms voru með minnst af fyllingum og tannátu hjá þessum aldurshópum. Hjá bæði 12 og 15 ára börnunum voru 12 ára jaxlar næst á eftir sex ára jöxlum hvað varðar fjölda fyllinga og tannátu sem náði inn í tannbein. Þegar fjórir til átta jaxlar voru skoðaðir sjónrænt og bornir saman við bestu skoðun (samsett sjónræn skoðun og röntgenskoðun) var næmi þess 69-77, hlutfall rétt flokkað 0,737-0,839 og Kappa 0,53-0,63. Skimun á öllum tönnum gaf næmið 78,8, hlutfall rétt flokkað 0,841 og Kappa 0,65 samanborið við bestu skoðun í gögnum MUNNÍS en 38,7% þeirra sem voru greind án tannátu með sjónrænni skimun allra tanna voru í raun með tannátu við bestu skoðun. Ályktun: Gæði skimunar allra tanna með sjónrænni skoðun eru ekki góð og gefur ekki rétta mynd af tannheilsu einstaklingsins þannig að ekki er réttlætanlegt að benda á ákveðnar lykiltennur fyrir slíka skimun.Introduction: The objective of this research was to analyse the location and distribution of dental caries to determine ig it would be possible to find key teeth or tooth surfaces in the assessment of dental caries in 12- and 15-year old children from the MUNNIS data (VSN 03-140) in 2005. Materials and methods: Data on dental caries in 12- and 15-year old children surveyed in MUNNIS (VSN 03-140) in 2005 were analysed (N=1.388 children) to see the distribution of dental caries and to analyse if it would be possible to find key teeth for the diagnosis of dental caries in children. Zero Inflated Poisson Regression, Agreement, Cohen´s Kappa and Sensitivity and Specificity were used to analyse the data. Results: First molars were most often affected by dental caries in both 12- and 15-year old children. Looking at the front teeth in the upper jaw, lateral incisors were those most at risk for dental caries in both age groups. Canines and incisors in the lower jaw were the least affected teeth in these age groups. In both 12-year old and 15-year old children, second molars were next to first molars when scoring the teeth most affected by dental caries. When four to eight molars were examined visually and compared with combined visual and X-ray examination then the sensitivity was 69-77, Agreement 0.737-0.839 and Kappa 0.53-0.63. Screening all teeth gave sensitivity of 78.8, Agreement of 0.841 and Kappa of 0.65 compared with combined visual and X-ray examination in MUNNIS data and 38.7% of those diagnosed without caries did in fact have caries. Conclusion: The quality of screening all teeth by visual examination is not good enough to allow one to point out certain key teeth for such screening and the screening do not give an accurate picture of the individuals dental health

Large Rotations of Crustal Blocks in the Tjörnes Fracture Zone of Northern Iceland

The interpretation of uppermost crustal deformation near oceanic transform faults is based on bathymetric lineaments and earthquake focal mechanisms, and relatively little is known about the detailed kinematics within the transform tectonized zone. The Tjörnes Fracture Zone is a broad zone of deformation produced by right‐lateral transform shearing in north Iceland and is partly exposed on land providing the opportunity to study shallow‐level crustal structure of mid‐Miocene, thick, oceanic‐like crust formed by subaerial spreading. A pronounced structural curvature of lava and dike orientations near the Húsavík‐Flatey Fault within the transform zone is well documented, yet of controversial origin. In order to develop an assessment of deformation near the transform zone, samples of lavas and dikes were collected from 182 paleomagnetic sites within eight structural localities across the deformation zone on the Flateyjarskagi Peninsula. A progressive clockwise increase in locality mean remanence declinations over more than 10 km south of the fault broadly mimics the structural curvature of lava and dike orientations. Rotation estimates based on inclined rotation axes indicate significant clockwise rotation (74° ± 7° to 96° ± 9°) of multiple crustal blocks. When combined, all data from 108 sites within the deformed zone \u3c12 km to the Húsavík‐Flatey Fault yield a best fit inclined axis rotation of 55° ± 7°. The paleomagnetic data and field relationships are consistent with a modified bookshelf faulting model, with relatively small (~1 km across) independently rotated crustal blocks with variable, and in some cases large‐magnitude rotations found within 10 km to the transform fault zone. Similar crustal deformation and comparable amounts of rotation may be present near other oceanic transforms, where accessibility and surficial deposits may limit documentation of more complex fault structures

A cascade of warming impacts brings bluefin tuna to Greenland waters

Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predator-prey dynamics in food webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species in ecological isolation from others. Here, we show that a large highly migratory top predator fish species has entered a high latitude subpolar area beyond its usual range. Bluefin tuna, Thunnus thynnus Linnaeus 1758, were captured in waters east of Greenland (65°N) in August 2012 during exploratory fishing for Atlantic mackerel, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9–11 °C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed to a warming trend since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species to the region. We conclude that a cascade of climate change impacts is restructuring the food web in east Greenland waters