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Rock‐slope failures (RSFs) constitute significant natural hazards, but the geophysical processes that control their timing are poorly understood. However, robust chronologies can provide valuable information on the environmental controls on RSF occurrence: information that can inform models of RSF activity in response to climatic forcing. This study uses Schmidt‐hammer exposure‐age dating (SHD) of boulder deposits to construct a detailed regional Holocene chronology of the frequency and magnitude of small rock‐slope failures (SRSFs) in Jotunheimen, Norway. By focusing on the depositional fans of SRSFs (≤103 m3), rather than on the corresponding features of massive RSFs (~108 m3), 92 single‐event RSFs are targeted for chronology building. A weighted SHD age–frequency distribution and probability density function analysis indicated four centennial‐ to millennial‐scale periods of enhanced SRSF frequency, with a dominant mode at ~4.5 ka. Using change detection and discreet Meyer wavelet analysis, in combination with existing permafrost depth models, we propose that enhanced SRSF activity was primarily controlled by permafrost degradation. Long‐term relative change in permafrost depth provides a compelling explanation for the high‐magnitude departures from the SRSF background rate and accounts for: (i) the timing of peak SRSF frequency; (ii) the significant lag (~2.2 ka) between the Holocene Thermal Maximum and the SRSF frequency peak; and (iii) the marked decline in frequency in the late‐Holocene. This interpretation is supported by geomorphological evidence, as the spatial distribution of SRSFs is strongly correlated with the aspect‐dependent lower altitudinal limit of mountain permafrost in cliff faces. Results are indicative of a causal relationship between episodes of relatively warm climate, permafrost degradation and the transition to a seasonal‐freezing climatic regime. This study highlights permafrost degradation as a conditioning factor for cliff collapse, and hence the importance of paraperiglacial processes; a result with implications for slope instability in glacial and periglacial environments under global warming scenarios. [ABSTRACT FROM AUTHOR]

Matthews, J. A. & Winkler, S. 2010: Schmidt-hammer exposure-age dating (SHD): application to early Holocene moraines and a reappraisal of the reliability of terrestrial cosmogenic-nuclide dating (TCND) at Austanbotnbreen, Jotunheimen, Norway. Boreas, 10.1111/j.1502-3885.2010.00178.x. ISSN 0300-9483. Schmidt-hammer exposure-age dating (SHD) and terrestrial cosmogenic-nuclide dating (TCND) are complementary techniques that can be used for mutual testing. SHD is low-cost but requires local control points of known age and may be affected by local geological variation and other environmental factors that influence weathering rates. TCND is vulnerable to the occurrence of anomalous boulders, other geomorphological uncertainties and the effects of snow-shielding at high altitudes. Both techniques are sensitive to post-depositional disturbances if other than solid bedrock is sampled. SHD was applied to two moraine ridges beyond the Little Ice Age limit of Austanbotnbreen in the Hurrungane massif, southern Norway. Independent regional and experimental local age-calibration curves were used to reappraise previous TCND results. Neither the two boulder surfaces nor their proximal bedrock surfaces could be differentiated statistically in terms of SHD exposure ages or their mean R-values (±95% confidence intervals), which ranged from 40.73±1.72 to 43.34±0.69. The best of the independent regional-calibration curves produced SHD exposure ages of 9413±723 and 9304±602 years, which are consistent with moraine formation early ( c. 10.2 ka) and late ( c. 9.7 ka) within the late-Preboreal Erdalen Event. The current precision of SHD, as reflected in 95% confidence intervals of ±500-900 years, enables rejection of a Finse Event ( c. 8.2 ka) age for either moraine. Results are consistent with a retracted Austanbotnbreen between the Erdalen Event and the Little Ice Age, and a modified model of Neoglaciation. [ABSTRACT FROM AUTHOR]

Surface exposure–age dating was applied to rock surfaces associated with ice‐marginal moraines at elevations of ~1520–1780 m a.s.l. on the slopes of Galdhøpiggen and Glittertinden, the two highest mountains in Scandinavia located in the Jotunheimen mountains of central southern Norway. This is important for understanding the pattern and timing of wastage of the Scandinavian Ice Sheet at the Younger Dryas–Holocene transition. Cosmogenic exposure dating (here 10Be dating) of boulders from the moraine ridges yielded overall mean ages (corrected for glacio‐isostatic uplift, surface erosion and snow shielding) of ~11.6 ka from Galdhøpiggen and ~11.2 ka from Glittertinden. Similar 10Be ages were also obtained from additionally collected proximal and distal erratic boulders and bedrock samples. These enabled age calibration of Schmidt‐hammer R‐values and independent Schmidt‐hammer exposure‐age dating (SHD) of the moraine ridges, which yielded comparable mean SHD ages of ~10.8 and ~10.6 ka from the Galdhøpiggen and Glittertinden sites, respectively. Taking account of the age resolution and other limitations of both dating techniques, the results suggest that the two sets of moraines have approximately the same age but that neither technique can distinguish unambiguously between moraine formation in the late Younger Dryas or Early Holocene. Together with features of moraine‐ridge morphology and estimates of equilibrium‐line altitude depression of ~360–575 m (corrected for land uplift), the results imply moraine formation during short‐lived re‐advances of active glaciers, at least the lower reaches of which were warm‐based. It is concluded that the local glaciers remained active and advanced during deglaciation either very late in the Younger Dryas or very early in the Holocene, possibly in response to the Preboreal Oscillation at ~11.4 ka. The study supports the concept of a thin Younger Dryas ice sheet and places time constraints on the timing of final deglaciation in southern Norway. [ABSTRACT FROM AUTHOR]

The article discusses the preservation of periglacial and glacial landforms of South Island (Te Wai Pounamu) of New Zealand (Aotearoa). It cites on the studies using cosmogenic nuclide of moraines to recostruct palaeoclimatic conditions in the country. The article also discusses that the studies are used as basis for climatic analysis and interchemispheric correlations.

Objective: The study was undertaken to assess the impact of B cell depletion on humoral and cellular immune responses to severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) vaccination in patients with various neuroimmunologic disorders on anti‐CD20 therapy. This included an analysis of the T cell vaccine response to the SARS‐CoV‐2 Delta variant. Methods: We investigated prospectively humoral and cellular responses to SARS‐CoV‐2 mRNA vaccination in 82 patients with neuroimmunologic disorders on anti‐CD20 therapy and 82 age‐ and sex‐matched healthy controls. For quantification of antibodies, the Elecsys anti‐SARS‐CoV‐2 viral spike (S) immunoassay against the receptor‐binding domain (RBD) was used. IFN‐gamma enzyme‐linked immunosorbent spot assays were performed to assess T cell responses against the SARS‐CoV‐2 Wuhan strain and the Delta variant. Results: SARS‐CoV‐2‐specific antibodies were found less frequently in patients (70% [57/82]) compared with controls (82/82 [100%], p < 0.001). In patients without detectable B cells (<1 B cell/mcl), seroconversion rates and antibody levels were lower compared to nondepleted (≥1 B cell/mcl) patients (p < 0.001). B cell levels ≥1 cell/mcl were sufficient to induce seroconversion in our cohort of anti‐CD20 treated patients. In contrast to the antibody response, the T‐cell response against the Wuhan strain and the Delta variant was more pronounced in frequency (p < 0.05) and magnitude (p < 0.01) in B‐cell depleted compared to nondepleted patients. Interpretation: Antibody responses to SARS‐CoV‐2 mRNA vaccinnation can be attained in patients on anti‐CD20 therapy by the onset of B cell repopulation. In the absence of B cells, a strong T cell response is generated which may help to protect against severe coronavirus disease 2019 (COVID‐19) in this high‐risk population. ANN NEUROL 2022;91:342–352 [ABSTRACT FROM AUTHOR]

Eur J Clin Invest 2011; 41 (10): 1071-1076 Abstract Background IFN-γ release assays (IGRA), widely used for latent tuberculosis screening prior to anti-TNF-α treatment, are limited by indeterminate results in patients under immunomodulatory (IM) therapy. The aim of our observational study was to delineate factors associated with indeterminate IGRA results. Methods A total of 190 patients with inflammatory bowel disease were included. IGRA was indeterminate if the result of IFN-γ concentration was < 0·35 IU mL−1 for tuberculosis-specific antigens and < 0·5 IU mL−1 for the positive control. Predictors for indeterminate results were delineated from multivariate logistic regression. Results IFN-γ release assays was indeterminate in 26/190 (13·7%) patients. Indeterminate IGRA were associated with lower serum albumin levels (odds ratio [OR] 0·88, 95% confidence interval [CI] 0·79-0·96), lower absolute lymphocyte count (OR 0·39, 95% CI 0·18-0·75) and double IM therapy (OR 2·98, 95% CI 0·95-8·90). Sub-analysis of IM therapy revealed an association of steroid therapy with indeterminate IGRA (OR 3·19, 95% CI 1·35-7·70). Hypoalbuminaemia increased the risk of indeterminate IGRA by (OR 2·97, 95% CI 1·03-8·61) and lymphopaenia by (OR 3·28, 95% CI 1·41-7·65). After a mean of 18·5 ± 14·4 days, retesting of IGRA in 18 patients with indeterminate results yielded 9 negative vs. 9 indeterminate results. Conclusions Our results reveal associations of indeterminate IGRA with low serum albumin levels and absolute lymphocyte count and double IM therapy. IGRA testing appears best to be performed prior to initiation of IM therapy in patients with inflammatory bowel disease. [ABSTRACT FROM AUTHOR]

ABSTRACT CD3[sup +] T cells are important sources of both pro- and anti-inflammatory cytokines during Plasmodium falciparum malaria. We studied the frequency of interleukin-2 (IL-2), gamma interferon (IFN-γ), tumour necrosis factor-alpha (TNF-α) and IL-10 expressing CD3[sup +] cells in 10 non-immune malaria patients with uncomplicated malaria and in one patient with cerebral malaria after P. falciparum-specific and non-specific mitogenic stimulation. Analysis by fluorescence-activated cell sorting was performed after drug-induced clearance of parasites to allow previously sequestered T cells to be detected in peripheral blood. CD3[sup +] cells of patients responded to P. falciparum infected erythrocytes with significant increases in the percentage of IL-2, IFN-γ, and TNF-α, but also IL-10, positive cells. CD3[sup +] cells from malaria-naïve donors were also responsive to specific stimulation albeit to a much lesser extent. Mitogenic stimulation of PBMC revealed no significant differences between cells of patients and controls. CD3[sup +] cells of the patient with cerebral malaria were hyporesponsive both to the infecting parasite isolate as well as to our laboratory-adapted P. falciparum isolate, whereas two patients with uncomplicated disease were more responsive to their infecting parasites than to the laboratory-adapted isolate. The results indicate that the increased responsiveness of in vivo primed compared to malaria-naïve CD3[sup +] cells is Plasmodium-specific and biased towards production of IFN-γ and TNF-α. [ABSTRACT FROM AUTHOR]