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The Upper Doubs River Valley is a 910-km2watershed feeding into Lake Chaillexon. The lake was formed by a natural rockfall at the end of the Bølling Chronozone (around 14,250 cal yr B.P.) and since then has trapped material eroded from the watershed. The filling process and variations in sediment yield have been investigated by mechanical coring, seismic surveys, and electric soundings. The detrital sediment yield of the upstream watershed can be calculated by quantifying the sedimentary stocks for each climatic stage of the Late-Glacial period and Holocene Epoch and estimating the lake's entrapment capacity. This enables us to determine the intensity of the erosion processes in relation to climate and environmental factors. The Bølling–Allerød Interstade produced the greatest yields with mean values of 19,500 metric tons per calendar year (t/yr). The Younger Dryas Chronozone saw a sharp fall (8900 t/yr) that continued into the Preboreal (2100 t/yr). Clastic supply increased during the Boreal (4500 t/yr) before declining again in the Early Atlantic (2400 t/yr). Since then, yields have risen from 4500 t/yr in the Late Atlantic to 6800 t/yr in the Subboreal and 11,100 t/yr in the Subatlantic. Comparison of quantitative data with the qualitative analysis of the deposits and with the paleohydrologic curve of the watershed based on level fluctuations in lakes around Chaillexon shows that climate was the controlling factor of sediment yield until the Late Atlantic. From the Late Atlantic–Subboreal around 5400 cal yr B.P. (470014C yr B.P.) and especially from the end of the Subboreal Chronozone and during the Subatlantic Chronozone (2770 cal yr B.P./270014C yr B.P.–present) climatic constraints have been compounded by human activity related to forest clearing and land use.
Agriculture in southern Greenland has a two-phase history: with the Norse, who first settled and farmed the region between 985ad and circa 1450ad, and with the recent reintroduction of sheep farming (1920ad to the present). The agricultural sector in Greenland is expected to grow over the next century as anticipated climate warming extends the length of the growing season and increases productivity. This article presents a synthesis of results from a well-dated 1500-year lake sediment record from Lake Igaliku, south Greenland (61°00′N, 45°26′W, 15m asl) that demonstrates the relative impacts of modern and Norse agricultural activities. Pollen, non-pollen palynomorphs (NPPs), sediment mass accumulation rates, diatoms and stable isotopes of nitrogen provide a comprehensive history of both phases of agriculture and their associated impacts on the landscape and adjacent lake. The initial colonisation of southern Greenland is marked by a loss of tree birch pollen, a rise in weed taxa, and an increase in coprophilous fungi and sediment accumulation rate consistent with land-use changes. The biological and chemical proxies within the lake, however, show only slight changes in diatom taxa, and a rise in δ15N. After the Norse demise and during the Little Ice Age, most of the markers return to pre-settlement conditions. However, the continuation of non-indigenous plant taxa suggests that the landscape did not completely return to a pre-disturbance state. After 1988, the character of the lake changed markedly: mesotrophic diatoms and N isotopes all reveal major shifts consistent with a trophic shift, together with a sharp rise in sediment accumulation rate. The post-1988 lake environment, affected by modern farming development, is unprecedented within the context of the last 1500 years. These results demonstrate the potential of lake sediment studies paired with archaeological investigations to reveal the relationship between climate, environment and human societies.
In the framework of the study of long-term storage of the spent nuclear fuel, polycrystalline UO2 samples have been implanted with He ions. The thin implanted layer, close to the free surface is subjected to elastic stresses which are studied by x-ray diffraction (micro Laue diffraction) and a mechanical modeling. A simple expression of the displacement gradient tensor has been evidenced; it concerns only three terms (ε3, ε4 and ε5) which strongly evolve with considered grain orientations. Finally, we show that results obtained with micro diffraction are in very good agreement with conventional x-ray diffraction measurements done in laboratory at macro scale.
The energy systems that provide the “life blood” to cities are as complex and diverse as cities themselves. Reflecting local natural resource and economic conditions, supply chains that may extend globally, historic investments in technology, and cultural and political preferences, urban energy systems serve as either a key accelerator or brake on the vitality and prospects of a city or urban region. Because of this, the local energy system can be of great interest to policymakers in a city, and many have begun to develop plans that seek to change one or more aspects of this system over the coming decades.
Climate change concerns are increasingly a key driver behind these changes, with local authorities seeking to reduce their city's current level of contribution to global climate change. Climate is not the only reason local authorities engage on energy issues, however. In some cases, cities are seeking to ameliorate pollution attributable to local energy use, while in other cities, economic development is a key concern. The latter is particularly prominent in developing countries, where a lack of access to adequate, reliable energy services continues to impede the economic growth of many cities (UNDP/WHO, 2009). In these situations, climate-related concerns are often secondary to efforts to improve access to modern energy services to reduce poverty, allow for new types of economic activity, and improve public health.
Heterodyne optical feedback on a class B laser is investigated for Scanning Near field Optical Microscopy (SNOM). All-fiberized set-up combining an Er-doped Distributed Feedback (DFB) fiber laser, a pair of pigtailed acousto-optics modulators (AOM) and a shear-force based scanning probe technique has been developed for the simultaneous observation of topography and evanescent light field on integrated optical devices. First demonstration of imaging using this technique is illustrated by characterizing the propagating modes into a rib waveguide at 1.54μm. Comparison between a theoretical model based on beam propagation mode (BPM) simulations and experimental measurements validates the results.
The diagnosis and treatment for paediatric and congenital cardiac disease has undergone remarkable progress over the last 60 years. Unfortunately, this progress has been largely limited to the developed world. Yet every year approximately 90% of the more than 1,000,000 children who are born with congenital cardiac disease across the world receive either suboptimal care or are totally denied care.
While in the developed world the focus has changed from an effort to decrease post-operative mortality to now improving quality of life and decreasing morbidity, which is the focus of this Supplement, the rest of the world still needs to develop basic access to congenital cardiac care. The World Society for Pediatric and Congenital Heart Surgery [http://www.wspchs.org/] was established in 2006. The Vision of the World Society is that every child born anywhere in the world with a congenital heart defect should have access to appropriate medical and surgical care. The Mission of the World Society is to promote the highest quality comprehensive care to all patients with pediatric and/or congenital heart disease, from the fetus to the adult, regardless of the patient’s economic means, with emphasis on excellence in education, research and community service.
We present in this article an overview of the epidemiology of congenital cardiac disease, the current and future challenges to improve care in the developed and developing world, the impact of the globalization of cardiac surgery, and the role that the World Society should play. The World Society for Pediatric and Congenital Heart Surgery is in a unique position to influence and truly improve the global care of children and adults with congenital cardiac disease throughout the world [http://www.wspchs.org/].
A number of mitochondrial (mt) tRNAs have strong structural
deviations from the classical tRNA cloverleaf secondary
structure and from the conventional L-shaped tertiary structure.
As a consequence, there is a general trend to consider all
mitochondrial tRNAs as “bizarre” tRNAs. Here,
a large sequence comparison of the 22 tRNA genes within 31
fully sequenced mammalian mt genomes has been performed to
define the structural characteristics of this specific group
of tRNAs. Vertical alignments define the degree of
conservation/variability of primary sequences and secondary
structures and search for potential tertiary interactions
within each of the 22 families. Further horizontal alignments
ascertain that, with the exception of serine-specific tRNAs,
mammalian mt tRNAs do fold into cloverleaf structures with
mostly classical features. However, deviations exist and
concern large variations in size of the D- and T-loops. The
predominant absence of the conserved nucleotides G18G19 and
T54T55C56, respectively in these loops, suggests that classical
tertiary interactions between both domains do not take place.
Classification of the tRNA sequences according to their genomic
origin (G-rich or G-poor DNA strand) highlight specific features
such as richness/poorness in mismatches or G-T pairs in stems
and extremely low G-content or C-content in the D- and T-loops.
The resulting 22 “typical” mammalian mitochondrial
sequences built up a phylogenetic basis for experimental structural
and functional investigations. Moreover, they are expected to help
in the evaluation of the possible impacts of those point mutations
detected in human mitochondrial tRNA genes and correlated with
In vitro transcription with T7 RNA polymerase is
one of the most powerful tools in RNA research. This is
mainly linked to the easy preparation of the enzyme, the
quite unlimited range of sizes and sequences of the RNA
that can be synthesized, as well as the efficiency and
accuracy of synthesis. So far only two major limitations
are common knowledge, namely poor transcription efficiency
of non-G-rich initial sequences (Dunn & Studier, 1983)
and 3′-end heterogeneities of the transcripts by
1 or 2 nt (Milligan et al., 1987; Draper et al., 1988;
Kholod et al., 1998). These drawbacks have been overcome
in most cases by improving the initiating sequence and/or
purifying the transcription products to single-nucleotide
resolution when necessary. The Uhlenbeck laboratory has
published the first evidence for shifty errors by the T7
RNA polymerase at the very 5′ end of the synthesized
RNA, an as yet unsuspected event (Pleiss et al., 1998).
They demonstrated that in the particular case of tRNA sequences
starting with G-rich stretches, the enzyme incorporates
additional nontemplated G residues in up to 30% of the
transcripts. The authors point to the fact that these errors,
in combination with the 3′-end heterogeneity common
to T7 transcripts, may be crucial, for instance, for functional
studies of tRNAs, because some in vitro-transcribed tRNA
molecules of rigorously correct final size may be erroneously
considered as functional.
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