Documentation of glacier changes is a key element for reconstruction of past climate variability and early detection of global climate change. In this paper, records of Holocene glacier variations in ...different regions in Norway have been synthesised. During the period from approximately 8000 to 4000 cal. yr BP, most glaciers in Norway were completely melted away at least once due to high summer temperatures and/or reduced winter precipitation. Lichenometrically and historically dated moraines at Jostedalsbreen, in Jotunheimen, at Hardangerjøkulen, and at Folgefonna were used to extend records of glacier length variations back to their maximum position during the ‘Little Ice Age’. The timing of the maximum ‘Little Ice Age’ glacial advance in different parts of southern Norway varied considerably, ranging from the early 18th century to the late 19th century. Cumulative glacier length variations of glaciers in southern Norway show an overall retreat from ∼
AD 1750 to the 1930s–40s. Thereafter, most Norwegian glaciers retreated significantly. Short maritime outlet glaciers with a short response time (<
10–15 yr) started to advance in the mid-1950s, whereas long outlet glaciers with longer frontal time lag (>
15–20 yr) continued their retreat to the 1980s. In the 1990s, however, several of the maritime glaciers started to advance as a response to higher winter accumulation during the first part of the 1990s. Since 2000 most of the observed glaciers have retreated remarkably fast (annual frontal retreat >
100 m) mainly due to high summer temperatures. The last glacier inventory in Norway published in 1988 shows that there were 1627 glaciers covering a total area of 2609 km
2 with an estimated volume of 164 km
3. Modern climate–glacier relationships from mass balance data in Scandinavia have been used to present possible effects on the Norwegian glaciers of climate scenarios between 1961–1990 and 2070–2100 presented by the ‘RegClim’ project. This long-term weather ‘forecast’ for western Norway indicates a rise in the summer temperature of 2.3 °C and an increase in the winter precipitation of 16% by the end of the 21st century. This climate scenario may, if it occurs, cause the equilibrium-line altitude (ELA) to rise 260
±
50 m. As a result, about 98% of the Norwegian glaciers are likely to disappear and the glacier area may be reduced ∼
34% by AD 2100.
The development of nutrition and health guidelines and policies requires reliable scientific information. Unfortunately, theoretical considerations and empirical evidence indicate that a large ...percentage of science-based claims rely on studies that fail to replicate. The session “Strategies to Optimize the Impact of Nutrition Surveys and Epidemiological Studies” focused on the elements of design, interpretation, and communication of nutritional surveys and epidemiological studies to enhance and encourage the production of reliable, objective evidence for use in developing dietary guidance for the public. The speakers called for more transparency of research, raw data, consistent data-staging techniques, and improved data analysis. New approaches to collecting data are urgently needed to increase the credibility and utility of findings from nutrition epidemiological studies. Such studies are critical for furthering our knowledge and understanding of the effects of diet on health.
A new approach to regional lichenometric dating is developed and applied to 'Little Ice Age' moraine-ridge sequences on 16 glacier forelands in Jotunheimen, southern Norway. Lichenometric-dating ...curves, based on the Rhizocarpon subgenus, are constructed independently for west, central and east Jotunheimen. Although there are differences between the subregions, a composite regional moraine chronology for Jotunheimen identifies 12 episodes of moraine formation in AD 1743-1750 (the regional 'Little Ice Age' glacier maximum), 1762-1771, 1782-1790, 1796-1802, 1811-1818, 1833-1838, 1845-1854, 1860-1868, 1871-1879, 1886-1898, 1915-1922 and 1927-1934. Spatialand temporalpatterns in glacier behaviour between the subregions and between Jotunheimen and the neighbouring Jostedalsbreen are explained in terms of the interaction of annual to decadal variations in summer temperature and winter precipitation: glacier advances and moraine-formation events driven primarily by winter-precipitation variations exhibit subregionalpatterns whil e summer-temperature forcing affects more synchronous glacier behaviour across the region. Regionally controlled lichenometric dating improves the accuracy of dating by up to about ±20 years on relatively old moraines and is dependent on regional patterns in the rate of lichen growth. On relatively young surfaces, mean cumulative growth rate declines from about 0.75 mm yr-1 in maritime west Jotunheimen to about 0.55 mm yr-1 in continentaleast Jotunheimen (though the differential in growth rate is less on older surfaces).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In the context of reconstruction of Holocene glacier chronologies, there has been a clear tendency during the past few decades towards imprecise use of the term ‘high resolution’. Furthermore, it ...seems to be increasingly assumed that recently developed terrestrial cosmogenic nuclide dating (TCND) is replacing earlier dating methods. Although recent glaciological knowledge clearly reveals the futility of oversimplified global and inter-hemispheric correlation on the basis of few ‘key’ sites, such comparisons are widely attempted. Stimulated by the example of a recently published article relating to the Southern Alps of New Zealand (Schaefer et al., 2009, Science 324: 622—625) we highlight some related potential problems with the interpretation of Holocene glacier chronologies. In particular, we consider (1) that the term ‘high resolution’ should be applied only to decadal-scale resolution or better and, therefore, not to TCND-based chronologies; (2) that discontinuous moraine chronologies should not be termed high resolution and that their potential geomorphological limitations should be acknowledged; and (3) that TCND-based moraine chronologies should not automatically replace evidence available from other dating techniques but that they should be regarded as complementary and an opportunity for mutual evaluation. Owing to local and regional patterns in glacier response to climate, it is concluded (4) that intra-hemispheric synchroneity in high-resolution Holocene glacier variations is still unproven, and hence (5) that inter-hemispheric comparison is arguably premature, if not impossible. Finally, it is suggested (6) that the first priority for research in this field should be to establish the spatial patterns in glacier behaviour evident at various scales in Holocene records.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Although estimates of suboptimal adherence to oral corticosteroids in asthma range from 30% to 50%, no ideal method for measurement exists; the impact of poor adherence in severe asthma is likely to ...be particularly high.
What is the prevalence of suboptimal adherence detected by self-reporting and direct measures? Is suboptimal adherence associated with disease activity?
Data were included from individuals with severe asthma taking part in the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) study and prescribed daily oral corticosteroids. Participants completed the Medication Adherence Report Scale, a five-item questionnaire used to grade adherence on a scale from 1 to 5, and provided a urine sample for analysis of prednisolone and metabolites by liquid chromatography-mass spectrometry.
Data from 166 participants were included in this study: mean (SD) age, 54.2 (± 11.9) years; FEV1, 65.1% (± 20.5%) predicted; female, 58%; 37% completing the Medication Adherence Report Scale reported suboptimal adherence; and 43% with urinary corticosteroid data did not have detectable prednisolone or metabolites in their urine. Good adherence by both methods was detected in 49 of the 142 (35%) of participants in whom both methods were performed; adherence detection did not match between methods in 53%. Self-reported high adherers had better asthma control and quality of life, whereas directly measured high adherers had lower blood eosinophil levels.
Low adherence is a common problem in severe asthma, whether measured directly or self-reported. We report poor agreement between the two methods, suggesting some disassociation between self-assessment of medication adherence and regular oral corticosteroid use, which suggests that each approach may provide complementary information in clinical practice.
Tephra layers are assuming an increasingly important role in the dating and correlation of Late Quaternary marine sequences. Here we demonstrate their potential by reporting a new study of the ...sediment sequence of marine core SA03-11, recovered from the Southern Adriatic Sea, which spans the last c. 39 ka. A total of 28 discrete tephra layers are reported from this sequence, 10 of which are visible in the core and a further 18 are non-visible cryptotephra layers. These have been analysed using more than 1400 WDS-EPMA measurements of glass chemistry and results have been compared with published chemical measurements obtained from relevant proximal and distal sites which preserve eruptive material dating to within the same time interval. The data show that a high proportion of the layers originate from the Campi Flegrei volcanic field but more distinctive layers are sourced from Vesuvius, the Aeolian Islands and Vulcano, and these provide key marker horizons. The results show that the sequence extends in time to the Campanian Ignimbrite at the base, that a number of the layers have robust age estimates that permit a better constrained age–depth model to be constructed for the sequence, and that the potential exists for importing terrestrially-based age estimates into marine contexts, thereby circumventing problems of incorporating reservoir uncertainties associated with marine radiocarbon dates. The WDS-EPMA dataset generated here also provides important new data that constrain key Late Quaternary tephra layers in the central Mediterranean region.
•28 tephra layers dated between 0 and 39 ka have been identified.•18 tephras are detected as cryptotephra, highlighting the value of this approach.•New tephra layers have been identified from the Campi Flegrei and Aeolian Islands.•We construct an age model for the core using terrestrial 14C and tephra information.•The results indicate the Adriatic has a varying 14C reservoir between 30 and 39 ka.
Age-related odontometric changes of human teeth Murray, Peter E.; Stanley, Harold R.; Matthews, John B. ...
Oral surgery, oral medicine, oral pathology, oral radiology and endodontics,
04/2002, Letnik:
93, Številka:
4
Journal Article
Recenzirano
Objective. The number of older patients requiring restorative treatment are likely to increase due to improvements in oral health and increased longevity. However, aging odontometric data are ...lacking. The aim of this study was to determine possible changes in pulp cell density, pulp area, and dentinal thickness with age. Study Design. Incisors (50), canines (39), premolars (51), and molars (7) extracted from 60 patients aged between 10 and 59 years, were analyzed histomorphometrically for cell density (odontoblasts, subodontoblasts, and pulp core fibroblasts) and dentinal thickness. Results. With increasing patient age, in both crown and root aspects of teeth, dentinal thickness increased (P <.001), while the density of odontoblasts (P <.001), subodontoblasts (P = 0.001), and pulp fibroblasts (crown, P <.011; root, P =.0015) decreased. The degree of age-related changes in teeth appeared to be asymmetrical, with decreases in the root being greater than in the crown. At all ages pulp cell densities, including odontoblasts, within the crown were greater than in the root (P <.001), even though the calculated rate of dentinal deposition was greatest in the root. Conclusion. Decreases in pulp cell density may reduce pulp repair activity after restorative treatments, although increases in dentinal thickness may aid pulp protection. An understanding of these age-related changes will influence the provision of restorative and endodontic care and benefit older patients. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:474-82)
The trajectories of acquired immunity to severe acute respiratory syndrome coronavirus 2 infection are not fully understood. We present a detailed longitudinal cohort study of UK healthcare workers ...prior to vaccination, presenting April-June 2020 with asymptomatic or symptomatic infection. Here we show a highly variable range of responses, some of which (T cell interferon-gamma ELISpot, N-specific antibody) wane over time, while others (spike-specific antibody, B cell memory ELISpot) are stable. We use integrative analysis and a machine-learning approach (SIMON - Sequential Iterative Modeling OverNight) to explore this heterogeneity. We identify a subgroup of participants with higher antibody responses and interferon-gamma ELISpot T cell responses, and a robust trajectory for longer term immunity associates with higher levels of neutralising antibodies against the infecting (Victoria) strain and also against variants B.1.1.7 (alpha) and B.1.351 (beta). These variable trajectories following early priming may define subsequent protection from severe disease from novel variants.
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