| 1. |
- Atto, Naures, et al.
(författare)
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Integration Policies, Practices and Experiences – United Kingdom Country Report
- 2020
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Rapport (refereegranskat)abstract
- This report provides an overview of the legal and policy framework of integration policies in the UK and explains the main contours of immigrant integration. The report looks into policies (macro-level), practices of stakeholders (meso-level) and experiences of immigrants (microlevel) in five thematic fields: a) labour market, b) education, c) housing and spatial integration, d) psychosocial health and e) citizenship and belonging. The report draws on interviews with asylum seekers and refugees at the micro level, and with stakeholders from NGOs and local authorities who are involved in the implementation of integration policies at the meso level.The main contribution of this study lies in its micro empirical focus by bringing in ethnographic insights from the perspective of asylum seekers and refugees based on their experiences vis-à-vis migration and integration policies. These individual accounts show us how asylum seekers and refugees are struggling to establish a new home in the UK and at a different level, in developing a belonging to a new place of living, while expressing their frustrations and hopes, their secondary traumas and resilience. In other words, they inform us about their integration experiences in society.
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| 2. |
- Ebrahimi-Fakhari, Darius, et al.
(författare)
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Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia
- 2020
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Ingår i: Brain. - OXFORD ENGLAND : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 143:10, s. 2929-2944
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Tidskriftsartikel (refereegranskat)abstract
- Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 +/- 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 +/- 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 +/- 5.1 years, SD) and later tetraplegia (mean age: 16.1 +/- 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 +/- 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 +/- 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.
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| 3. |
- Gaspard, François, et al.
(författare)
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Quantifying Non-Thermal Silicate Weathering Using Ge/Si and Si Isotopes in Rivers Draining the Yellowstone Plateau Volcanic Field, USA
- 2021
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Ingår i: Geochemistry, Geophysics, Geosystems. - 1525-2027. ; 22:11
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Tidskriftsartikel (refereegranskat)abstract
- In active volcanic regions, high-temperature chemical reactions in the hydrothermal system consume CO2 sourced from magma or from the deep crust, whereas reactions with silicates at shallow depths mainly consume atmospheric CO2. Numerous studies have quantified the load of dissolved solids in rivers that drain volcanic regions to determine chemical weathering rates and atmospheric CO2 consumption rates. However, the balance between thermal and non-thermal components to riverine fluxes in these areas remains poorly constrained, hindering accurate estimates of atmospheric CO2 consumption rates. Here we use the Ge/Si ratio and the stable silicon isotopes (δ30Si) as tracers for quantifying non-thermal silicon contributions in rivers draining the Yellowstone Plateau Volcanic Field, USA. The Ge/Si ratio (µmol.mol−1) was determined for seven thermal water samples (183 ± 22), eight rivers (35 ± 23) and six creeks flowing into Yellowstone Lake (5 ± 3) during base flow and during peak water discharge following snowmelt. The δ30Si value (‰) was determined for thermal waters (−0.09 ± 0.04), Yellowstone River at Yellowstone Lake outlet (1.91 ± 0.23) and creek samples (0.82 ± 0.29). The calculated atmospheric CO2 consumption associated with non-thermal waters flowing through Yellowstone's rivers during peak discharge is ∼3.03 ton.km−2.yr−1, which is ∼2% of the annual mean atmospheric CO2 consumption in other volcanic regions. This study highlights the significance of quantifying seasonal variations in chemical weathering rates for improving estimates of atmospheric CO2 consumption rates in active volcanic regions.
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| 4. |
- Hirst, Catherine, et al.
(författare)
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Characterisation of Fe-bearing particles and colloids in the Lena River basin, NE Russia
- 2017
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Ingår i: Geochimica et Cosmochimica Acta. - Cambridge : Elsevier. - 0016-7037 .- 1872-9533. ; 213, s. 553-573
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Tidskriftsartikel (refereegranskat)abstract
- Rivers are significant contributors of Fe to theocean. However, the characteristics of chemically reactive Fe remain poorly constrained, especially in large Arctic rivers, which drain landscapes highly susceptible to climate change and carbon cycle alteration. The aim of this study was a detailed characterisation (size, mineralogy, and speciation) of riverine Fe-bearing particles (> 0.22 µm) and colloids (1 kDa – 0.22 µm) and their association with organic carbon (OC), in the Lena River and tributaries, which drain a catchment almost entirely underlain by permafrost. Samples fromthe main channel and tributaries representing watersheds that span a wide rangein topography and lithology were taken after the spring flood in June 2013 and summer baseflow in July 2012. Fe-bearing particles were identified, usingTransmission Electron Microscopy, as large (200 nm – 1 µm) aggregates of smaller (20 nm - 30 nm) spherical colloids of chemically-reactive ferrihydrite.In contrast, there were also large (500 nm – 1 µm) aggregates of clay (illite) particles and smaller (100 - 200 nm) iron oxide particles (dominantly hematite) that contain poorly reactive Fe. TEM imaging and Scanning Transmission X-raymicroscopy (STXM) indicated that the ferrihydrite is present as discrete particles within networks of amorphous particulate organic carbon (POC) and attached to the surface of primary produced organic matter and clay particles.Together, these larger particles act as the main carriers of nanoscale ferrihydrite in the Lena River basin. The chemically reactive ferrihydrite accounts for on average 70 ± 15 % of the total suspended Fe in the Lena River and tributaries. These observations place important constraints on Fe and OC cycling in the Lena River catchment area and Fe-bearing particle transport to the Arctic Ocean.
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| 5. |
- Hirst, Catherine, 1989-
(författare)
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Iron in the Lena River basin, NE Russia : Insights from microscopy, spectroscopy and isotope analysis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Iron is an important mediator of biotic and abiotic processes on the Earth’s surface, being an electron acceptor in organic matter degradation, a surface for organic matter and trace element adsorption, and a required element for enzymatic processes during primary production. Yet, the role of iron as a mediator of carbon and trace element cycling in high latitude, permafrost-dominated regions remains poorly investigated. The aim of this study was to characterise the chemical reactivity (by size separation, microscopy and spectroscopy) and sources (by isotope composition) of Fe in the Lena River and major tributaries, spanning a wide range in lithology, topography and climate. The Fe transported in the Lena River and major tributaries carries an integrated signal of Fe weathering processes across the permafrost-dominated terrain.A spatial sample set was collected during the post-spring flood period (July 2012, June 2013), from the main channel and tributaries draining contrasting topography and permafrost extent. Across the basin, Fe is mainly transported as chemically reactive ferrihydrite that spans the particulate (> 0.22 µm) and colloidal (0.22 µm – 1 kDa) fractions. The remaining Fe transported as poorly reactive detrital Fe in clays and crystalline oxides. Fe is transported in larger size fractions than the dissolved OM showing that Fe is not a major carrier of DOM. Nano-sized ferrihydrite was attached to OM in the particulate fraction, evidence of a Fe – OM particle association in the Lena River basin.Ferrihydrite shows distinct isotope values in particulate and colloidal fractions, showing that there is a difference in isotopic composition between different size fractions of the same mineral. A conceptual model was developed to understand ferrihydrite formation in the riparian zone of the Lena River and tributaries. Particulate ferrihydrite has isotope values lower than crustal values resulting from redox and organic-ligand promoted mineral dissolution and precipitation of Fe(II)aq to form coatings of ferrihydrite on particles in the riparian zone. Ferrihydrite colloids span a wider range of isotope values, higher than Fe particles, resulting from variations in the size and isotope composition of the Fe(II)aq pool transported in soil groundwaters, and the isotope fractionation factor for Fe oxidation and organic complexation.A temporal sample set was collected in the main channel between September 2012 – March 2013 and every three days during May 2015. The colloidal Fe shows distinct seasonal Fe isotope signatures and Fe fluxes, with isotope values lower than crustal during winter baseflow, overlying crustal values during spring flood and higher than crustal values during summer, attributed to changing sources and thus conditions for isotope fractionation. The combined understanding of Fe reactivity and isotope composition allows us to isolate the dominant sources of Fe entering the Lena River.
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| 6. |
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| 7. |
- Hirst, Catherine, 1989-, et al.
(författare)
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Iron isotopes reveal seasonal variations in the mechanisms for iron-bearing particle and colloid formation in the Lena River catchment, NE Siberia
- 2023
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Ingår i: Geochimica et Cosmochimica Acta. - 0016-7037 .- 1872-9533. ; 363, s. 77-93
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Tidskriftsartikel (refereegranskat)abstract
- Large Arctic rivers are an important source of iron (Fe) to the Arctic Ocean, though seasonal variations in the terrestrial source and supply of Fe to the ocean are unknown. To constrain the seasonal variability, we present Fe concentrations and isotopic compositions (δ56Fe) for particulate (>0.22 µm) and colloidal (<0.22 µm–1 kDa) Fe from the Lena River, NE Russia. Samples were collected every month during winter baseflow (September 2012–March 2013) and every 2–3 days before, during and after river ice break-up (May 2015).Iron in particles have isotope ratios lower than crustal values during winter (e.g., δ56FePart = −0.37 ± 0.16‰), and crustal-like values during river ice break-up and spring flood (e.g., δ56FePart = 0.07 ± 0.08‰), indicating a change in the source of particulate Fe between winter and spring flood. Low isotope values are indicative of mineral dissolution, transport of reduced Fe in sub-oxic, ice-covered sub-permafrost groundwaters and near-quantitative precipitation of Fe as particles. Crustal-like isotopic compositions result from the increased supply of detrital particles from riverbank and soil erosion during river ice break-up and flooding. Iron colloids (<0.22 μm) have δ56Fe values that are comparable to or lower than crustal values during winter (e.g., δ56FeCol = −0.08 ± 0.05‰) but similar to or higher than crustal values during spring flood (e.g., δ56FeCol = +0.24 ± 0.11‰). Low δ56Fe ratios for colloidal Fe during winter are consistent with precipitation from isotopically light Fe(II)aq transported in sub-permafrost groundwaters. Higher colloidal δ56Fe ratios during the spring flood indicate that these colloids are supplied from surface soils, where Fe is fractionated via oxidation or organic carbon complexation, similar to during summer. Approximately half of the annual colloidal Fe flux occurs during spring flood while most of the remaining colloidal Fe is supplied during summer months. The total amount of colloidal Fe transported during winter was relatively low. The seasonal variation in colloidal Fe isotope values may be a useful tool to trace the source of colloidal Fe to the Arctic Ocean and monitor future changes in the sources and supply of Fe from the permafrost landscape to the Lena River basin.
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| 8. |
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| 9. |
- Hirst, Catherine, et al.
(författare)
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Iron isotopes reveal the sources of Fe-bearing particles and colloids in the Lena River basin
- 2020
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 269, s. 678-692
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Tidskriftsartikel (refereegranskat)abstract
- Large Arctic rivers are important suppliers of iron to the Arctic Ocean. However, the sources of Fe-bearing particles in permafrost-dominated systems and the mechanisms driving this supply of Fe are poorly resolved. Here, Fe isotope ratios were used to determine the sources of Fe-bearing particles and colloids in the Lena River and tributaries. In samples collected after the spring floods, Fe-bearing particles (>0.22 mu m) carried similar to 70% of the Fe and have isotope ratios that are lower than, or similar to that of the continental crust. These particles are composed of a leachable Fe fraction of largely ferrihydrite, with isotope values of -1.40 parts per thousand to -0.12 parts per thousand, and a fraction of clays and Fe oxides with continental crust values. Co-existing Fe-bearing colloids (<0.22 mu m), composed mainly of ferrihydrite, have higher isotope values, of -0.22 parts per thousand to +1.83 parts per thousand. A model is proposed in which soil mineral weathering generates aqueous Fe with lower delta Fe-56 values. During transport, a small fraction of the dissolved Fe is precipitated as colloidal ferrihydrite with higher delta Fe-56 values. Most of the Fe is precipitated onto mineral grains in oxic riparian zones, with the delta Fe-56 values largely generated during weathering. Groundwater discharge and riparian erosion supply the colloids and coated particles to the rivers. The differences between delta Fe-56 values in leachates and detrital grains in Fe-bearing particles agree with values determined in mineral dissolution experiments and in Fe accumulation horizons in soils. The difference in delta Fe-56 values between leachates and colloids reflects isotope fractionation during incremental Fe(III)(aq) precipitation and Fe-OC complexation during transport towards the riparian zone. Overall, the Fe isotope values of riverine particles and colloids reflect processes that occur during mineral dissolution, transport, and secondary mineral formation in permafrost soils.
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| 10. |
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| 11. |
- Hirst, Catherine, et al.
(författare)
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United Kingdom - Country Report : Legal and Policy Framework of Migration Governance
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report explores the legal and policy framework of migration governance in the United Kingdom (UK). It shows that migration governance is complicated, reactive, and that the needs of immigrants, refugees and asylum seekers have been eroded at the expense of border control overtime. The constitutional organisation of the state has contributed to these features of immigration policy. Evidence of the complexity, reactivity and restrictiveness of migration governance is found in the UK’s legislative framework, the legal status of foreigners, the reception system and post-refugee crisis reforms. Constitutionally there are three tiers of government in the UK – the central UK Government, the devolved governments of Northern Ireland, Scotland and Wales, and local authorities. The rights of asylum seekers are in a more precarious position than in other countries for two reasons. First, there is no specific right to asylum enshrined in the UK’s uncodified constitution, although the Human Rights Act 1998 plays a significant role in protecting asylum seeker rights. Second, the UK has no entrenched provisions in its constitution, meaning that legislation such as the Human Rights Act 1998 could be amended or replaced simply via an act of parliament. Evidence of the complexity, reactivity and restrictive nature of migration governance can be found in the evolution of legislation. With some notable exceptions, the evolution of primary legislation on immigration and asylum has been regressive, with successive restrictions on appeal rights, social benefits and the criminalization of irregular migrants. Legislation has been introduced to circumvent more progressive court decisions and has at times been rushed through without adequate consultation. Legislation has also tended to be reactive, with each wave of immigration throughout the 20th century being met with a legislative backlash.Routes to live in the UK are incredibly complex, with over 16 different types of work visa, which are being amended, removed and replaced all the time. The reception system for asylum seekers provides another example of the complexity and regressive nature of immigration governance, which fails to meet asylum seekers’ needs. Only destitute and unaccompanied asylum-seeking children have access to the reception system. The weekly allowance given to destitute asylum seekers is barely enough to make ends meet, while reception centre accommodation is not sensitive to the needs of vulnerable asylum seekers.Since the outbreak of the Syrian war, the Government has set up the Syrian Vulnerable Person Resettlement Scheme (VPRS), the Vulnerable Children Resettlement Scheme and children relocated under the ‘Dubs Amendment’. Advocates have been particularly critical of the implementation of the ‘Dubs Amendment’. The current immigration landscape notwithstanding, Brexit has generated significant ambiguity as to the future of UK migration governance. However, there are significant components of UK migration governance that will remain unaffected – the UK will still need to meet its obligations under the Convention Relating to the Status of Refugees 1951 (Refugee Convention) and the European Convention on Human Rights (ECHR), while Brexit will not directly affect the UK’s export of border controls to France2 (Gauci, 2017, p.3). The methodological approach of the report has been to rely on secondary research. Where possible, government documents, policies, legislation and publications have been used in order to gather information about the policy and legal environment directly from the source. This has been supplemented by third sector research reports, text books, academic journal articles, media articles and other public commentary.
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| 12. |
- Hudson, Thomas J., et al.
(författare)
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International network of cancer genome projects
- 2010
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 464:7291, s. 993-998
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Tidskriftsartikel (refereegranskat)abstract
- The International Cancer Genome Consortium (ICGC) was launched to coordinate large-scale cancer genome studies in tumours from 50 different cancer types and/or subtypes that are of clinical and societal importance across the globe. Systematic studies of more than 25,000 cancer genomes at the genomic, epigenomic and transcriptomic levels will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.
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| 13. |
- Jenei, Veronika, et al.
(författare)
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Nitric oxide produced in response to engagement of beta 2 integrins on human neutrophils activates the monomeric GTPases Rap1 and Rap2 and promotes adhesion
- 2006
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 281:46, s. 35008-35020
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Tidskriftsartikel (refereegranskat)abstract
- We found that engagement of beta 2 integrins on human neutrophils increased the levels of GTP-bound Rap1 and Rap2. Also, the activation of Rap1 was blocked by PP1, SU6656, LY294002, GF109203X, or BAPTA-AM, which indicates that the downstream signaling events in Rap1 activation involve Src tyrosine kinases, phosphoinositide 3-kinase, protein kinase C, and release of calcium. Surprisingly, the beta 2 integrin-induced activation of Rap2 was not regulated by any of the signaling pathways mentioned above. However, we identified nitric oxide as the signaling molecule involved in beta 2 integrin-induced activation of Rap1 and Rap2. This was illustrated by the fact that engagement of beta 2 integrins increased the production of nitrite, a stable end-product of nitric oxide. Furthermore, pretreatment of neutrophils with N-omega-mono-methy1-L-arginine, or 1400W, which are inhibitors of inducible nitric- oxide synthase, blocked beta 2 integrin-induced activation of Rap1 and Rap2. Similarly, R-P-8pCPT-cGMPS, an inhibitor of cGMP-dependent serine/threonine kinases, also blunted the beta 2 integrin-induced activation of Rap GTPases. Also nitric oxide production and its downstream activation of cGMP-dependent serine/threonine kinases were essential for proper neutrophil adhesion by beta 2 integrins. Thus, we made the novel findings that beta 2 integrin engagement on human neutrophils triggers production of nitric oxide and its downstream signaling is essential for activation of Rap GTPases and neutrophil adhesion.
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| 14. |
- Kutscher, Liselott, et al.
(författare)
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Spatial variation in concentration and sources of organic carbon in the Lena River, Siberia
- 2017
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Ingår i: Journal of Geophysical Research - Biogeosciences. - New York. - 2169-8953 .- 2169-8961. ; 122
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Tidskriftsartikel (refereegranskat)abstract
- Global warming in permafrost areas is expected to change fluxes of riverine organic carbon (OC) 22 to the Arctic Ocean. Here OC concentrations, stable carbon isotope signatures (δ13C) and carbon-23 nitrogen ratios (C/N) are presented from 22 sampling stations in the Lena River and 40 of its 24 tributaries. Sampling was conducted during two expeditions: the first in July 2012 in the south 25 and southeastern region and the second in June 2013 in the northern region of the Lena basin. 26 The data showed significant spatial differences in concentrations and major sources of OC. Mean 27 sub-catchment slopes were correlated with OC concentrations, implying that mountainous areas 28 in general had lower concentrations than lowland areas. δ13C and C/N data from tributaries 29 originating in mountainous areas indicated that both dissolved and particulate OC (DOC and 30 POC) were mainly derived from soil organic matter (SOM). In contrast, tributaries originating in 31 lowland areas had larger contributions from fresh vegetation to DOC, while aquatically produced 32 OC was the major source of POC. We suggest that these differences in dominant sources 33 indicated differences in dominant flow pathways. Tributaries with larger influence of fresh 34 vegetation probably had surficial flow pathways, while tributaries with more SOM influence had 35 deeper water flow pathways. Thus, the future export of OC to the Arctic Ocean will likely be 36 controlled by changes in spatial patterns in hydroclimatology and the depth of the active layers 37 influencing the dominant water flow pathways in Arctic river basins.
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| 15. |
- Murphy, Melissa, et al.
(författare)
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Tracingsilicate weathering processes in the permafrost-dominated Lena River watershedusing lithium isotopes
- 2019
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Ingår i: Geochimica et Cosmochimica Acta. - : Saunders Elsevier. - 0016-7037 .- 1872-9533. ; 245, s. 154-171
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Tidskriftsartikel (refereegranskat)abstract
- Increasing global temperatures are causing widespread changes in the Arctic, including permafrost thawing and altered freshwater inputs and trace metal and carbon fluxes into the ocean and atmosphere. Changes in the permafrost active layer thickness can affect subsurface water flow paths and water-rock interaction times, and hence weathering processes. Riverine lithium isotope ratios (reported as δ7Li) are tracers of silicate weathering that are unaffected by biological uptake, redox, carbonate weathering and primary lithology. Here we use Li isotopes to examine silicate weathering processes in one of the largest Russian Arctic rivers: the Lena River in eastern Siberia. The Lena River watershed is a large multi-lithological catchment, underlain by continuous permafrost. An extensive dataset of dissolved Li isotopic compositions of waters from the Lena River main channel, two main tributaries (the Aldan and Viliui Rivers) and a range of smaller sub tributaries are presented from the post-spring flood/early-summer period at the onset of active layer development and enhanced water-rock interactions. The Lena River main channel (average δ7Lidiss ~19‰) has a slightly lower isotopic composition than the mean global average of 23‰ (Huhet al., 1998a). The greatest range of [Li] and δ7Lidiss are observed in catchments draining the south facing slopes of the Verkhoyansk Mountain Range. South-facing slopes in high-latitude, permafrost dominated regions are typically characterised by increased summer insolation and higher daytime temperatures relative to other slope aspects. The increased solar radiation on south-facing catchments promotes repeated freeze-thaw cycles, and contributes to more rapid melting of snow cover, warmer soils, and increased active layer thaw depths. The greater variability in δ7Li and [Li] in the south-facing rivers likely reflect the greater infiltration of melt water and enhanced water rock interactions within the active layer. A similar magnitude of isotopic fractionation is observed between the low-lying regions of the Central Siberian Plateau (and catchments draining into the Viliui River), and catchments draining the Verkhoyansk Mountain Range into the Aldan River. This is in contrast to global rivers in non permafrost terrains that drain high elevations or areas of rapid uplift, where high degrees of physical erosion promote dissolution of freshly exposed primary rock typically yielding low δ7Lidiss, and low lying regions exhibit high riverine δ7Li values resulting from greater water-rock interaction and formation of secondary mineral that fractionates Li isotopes. Overall, the range of Li concentrations and δ7Lidiss observed within the Lena River catchment are comparable to global rivers located in temperate and tropical regions. This suggests that cryogenic weathering features specific to permafrost regions (such as the continual exposure of fresh primary minerals due to seasonal freeze-thaw cycles, frost shattering and salt weathering), and climate (temperature and runoff), are not a dominant control on δ7Li variations. Despite vastly different climatic and weathering regimes, the same range of riverine δ7Li values globally suggests that the same processes govern Li geochemistry – that is, the balance between primary silicate mineral dissolution and the formation (or exchange with) secondary minerals. This has implications for the use of δ7Li as a palaeo weathering tracer for interpreting changes in past weathering regimes.
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| 16. |
- Pallavicini, Nicola, et al.
(författare)
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Ranges of B, Cd, Cr, Cu, Fe, Pb, Sr, Tl, and Zn Concentrations and Isotope Ratios in Environmental Matrices from an Urban Area
- 2018
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Ingår i: Journal of Spectroscopy. - : Hindawi Publishing Corporation. - 2314-4920 .- 2314-4939. ; , s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Isotopic information may provide powerful insight into the elemental cycling processes which occur in natural compartments. Further implementation of isotopic techniques in natural sciences requires a better understanding of the range of elemental and isotopic compositional variability in environmental matrices. This study assesses the local-scale concentration and isotopic composition variability of nine elements: boron (B), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), strontium (Sr), thallium (Tl), and zinc (Zn) in lysimetric waters, mushrooms, litter, needles, leaves, and lichens. Sequential extractions were also performed on soil samples from 6 depth profiles providing more detailed information on the variability of elemental concentrations and isotope ratios between the elemental pools present in soil. For most of the sample types studied the range of isotopic variability between samples spans almost the entire ranges reported in the literature for natural samples. These results represent a starting point for discussing the role of natural variability in isotopic studies (for example, as a limiting factor in the use of isotopic mixing models) and a baseline for future in-depth studies examining the controls on isotope fraction in natural systems
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| 17. |
- Sun, Xiaole, et al.
(författare)
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Stable silicon isotopic compositions of the Lena River and its tributaries : Implications for silicon delivery to the Arctic Ocean
- 2018
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 241, s. 120-133
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Tidskriftsartikel (refereegranskat)abstract
- Silicon isotope values (delta Si-30(DSi)) of dissolved silicon (DSi) have been analyzed in the Lena River and its tributaries, one of the largest Arctic watersheds in the world. The geographical and temporal variations of delta Si-30(DSi) range from +0.39 to +1.86% with DSi concentrations from 34 to 121 mu M. No obvious patterns of DSi concentrations and delta Si-30(DSi) values were observed along over 200 km of the two major tributaries, the Viliui and Aldan Rivers. In summer, the variations of DSi concentrations and delta Si-30(DSi) values in the water are either caused by biological uptake by higher plants and phytoplankton or by mixing of water masses carrying different DSi concentrations and delta Si-30(DSi) values. DSi in tributaries from the Verkhoyansk Mountain Range seems to be associated with secondary clay formation that increased the delta Si-30(DSi) values, while terrestrial biological production is likely more prevalent in controlling delta Si-30(DSi) values in Central Siberian Plateau and Lena Amganski Inter-River Area. In winter, when soils were frozen, the delta Si-30(DSi) values in the river appeared to be controlled by weathering and clay formation in deep intrapermafrost groundwater. During the spring flood, dissolved silicate materials and phytoliths were flushed from the upper thawed soils into rivers, which reset delta Si-30(DSi) values to the values observed prior to the biological bloom in summer. The results indicate that the Si isotope values reflect the changing processes controlling Si outputs to the Lena River and to the Arctic Ocean between seasons. The annual average delta Si-30(DSi) value of the Lena Si flux is calculated to be +0.86 +/- 0.3 parts per thousand using measured delta Si-30(DSi) values from each season. Combined with the estimate of + 1.6 +/- 0.25 parts per thousand for the Yenisey River, an updated delta Si-30(DSi) value of the major river Si inputs to the Arctic Ocean is estimated to be + 1.3 +/- 0.3 parts per thousand. This value is expected to shift towards higher values in the future because of the impacts from a variety of biological and geochemical processes and sources under global warming.
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| 18. |
- Wang, Haidong, et al.
(författare)
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Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015 : a systematic analysis for the Global Burden of Disease Study 2015
- 2016
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Ingår i: The Lancet. - 0140-6736 .- 1474-547X. ; 388:10053, s. 1459-1544
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Improving survival and extending the longevity of life for all populations requires timely, robust evidence on local mortality levels and trends. The Global Burden of Disease 2015 Study (GBD 2015) provides a comprehensive assessment of all-cause and cause-specific mortality for 249 causes in 195 countries and territories from 1980 to 2015. These results informed an in-depth investigation of observed and expected mortality patterns based on sociodemographic measures.METHODS: We estimated all-cause mortality by age, sex, geography, and year using an improved analytical approach originally developed for GBD 2013 and GBD 2010. Improvements included refinements to the estimation of child and adult mortality and corresponding uncertainty, parameter selection for under-5 mortality synthesis by spatiotemporal Gaussian process regression, and sibling history data processing. We also expanded the database of vital registration, survey, and census data to 14 294 geography-year datapoints. For GBD 2015, eight causes, including Ebola virus disease, were added to the previous GBD cause list for mortality. We used six modelling approaches to assess cause-specific mortality, with the Cause of Death Ensemble Model (CODEm) generating estimates for most causes. We used a series of novel analyses to systematically quantify the drivers of trends in mortality across geographies. First, we assessed observed and expected levels and trends of cause-specific mortality as they relate to the Socio-demographic Index (SDI), a summary indicator derived from measures of income per capita, educational attainment, and fertility. Second, we examined factors affecting total mortality patterns through a series of counterfactual scenarios, testing the magnitude by which population growth, population age structures, and epidemiological changes contributed to shifts in mortality. Finally, we attributed changes in life expectancy to changes in cause of death. We documented each step of the GBD 2015 estimation processes, as well as data sources, in accordance with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER).FINDINGS: Globally, life expectancy from birth increased from 61·7 years (95% uncertainty interval 61·4-61·9) in 1980 to 71·8 years (71·5-72·2) in 2015. Several countries in sub-Saharan Africa had very large gains in life expectancy from 2005 to 2015, rebounding from an era of exceedingly high loss of life due to HIV/AIDS. At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence. From 2005 to 2015, male life expectancy in Syria dropped by 11·3 years (3·7-17·4), to 62·6 years (56·5-70·2). Total deaths increased by 4·1% (2·6-5·6) from 2005 to 2015, rising to 55·8 million (54·9 million to 56·6 million) in 2015, but age-standardised death rates fell by 17·0% (15·8-18·1) during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14·1% (12·6-16·0) to 39·8 million (39·2 million to 40·5 million) in 2015, whereas age-standardised rates decreased by 13·1% (11·9-14·3). Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias. By contrast, both total deaths and age-standardised death rates due to communicable, maternal, neonatal, and nutritional conditions significantly declined from 2005 to 2015, gains largely attributable to decreases in mortality rates due to HIV/AIDS (42·1%, 39·1-44·6), malaria (43·1%, 34·7-51·8), neonatal preterm birth complications (29·8%, 24·8-34·9), and maternal disorders (29·1%, 19·3-37·1). Progress was slower for several causes, such as lower respiratory infections and nutritional deficiencies, whereas deaths increased for others, including dengue and drug use disorders. Age-standardised death rates due to injuries significantly declined from 2005 to 2015, yet interpersonal violence and war claimed increasingly more lives in some regions, particularly in the Middle East. In 2015, rotaviral enteritis (rotavirus) was the leading cause of under-5 deaths due to diarrhoea (146 000 deaths, 118 000-183 000) and pneumococcal pneumonia was the leading cause of under-5 deaths due to lower respiratory infections (393 000 deaths, 228 000-532 000), although pathogen-specific mortality varied by region. Globally, the effects of population growth, ageing, and changes in age-standardised death rates substantially differed by cause. Our analyses on the expected associations between cause-specific mortality and SDI show the regular shifts in cause of death composition and population age structure with rising SDI. Country patterns of premature mortality (measured as years of life lost [YLLs]) and how they differ from the level expected on the basis of SDI alone revealed distinct but highly heterogeneous patterns by region and country or territory. Ischaemic heart disease, stroke, and diabetes were among the leading causes of YLLs in most regions, but in many cases, intraregional results sharply diverged for ratios of observed and expected YLLs based on SDI. Communicable, maternal, neonatal, and nutritional diseases caused the most YLLs throughout sub-Saharan Africa, with observed YLLs far exceeding expected YLLs for countries in which malaria or HIV/AIDS remained the leading causes of early death.INTERPRETATION: At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected on the basis of development measured by the SDI. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems.
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