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Tidewater glaciers in Greenland experienced widespread retreat during the last century. Information on their behaviour prior to this is often poorly constrained due to lack of observations, while determining the drivers prior to instrumental records is also problematic. Here we present a record of the dynamics of Kangiata Nunaata Sermia (KNS), southwest Greenland, from its Little Ice Age maximum (LIAmax) to 1859 – the period before continuous air temperature observations began at Nuuk in 1866. Using glacial geomorphology, historical accounts, photographs and GIS analyses, we provide evidence KNS was at its LIAmax by 1761, had retreated by ~5 km by 1808 and a further 7 km by 1859. This predates retreat at Jakobshavn Isbræ by 43–113 years, demonstrating the asynchroneity of tidewater glacier terminus response following the LIA. We use a one-dimensional flowband model to determine the relative sensitivity of KNS to atmospheric and oceanic climate forcing. Results demonstrate that terminus forcing rather than surface mass balance drove the retreat. Modelled glacier sensitivity to submarine melt rates is also insufficient to explain the retreat observed. However, moderate increases in crevasse water depth, driving an increase in calving, are capable of causing terminus retreat of the observed magnitude and timing.
Ten ice-sheet models are used to study sensitivity of the Greenland and Antarctic ice sheets to prescribed changes of surface mass balance, sub-ice-shelf melting and basal sliding. Results exhibit a large range in projected contributions to sea-level change. In most cases, the ice volume above flotation lost is linearly dependent on the strength of the forcing. Combinations of forcings can be closely approximated by linearly summing the contributions from single forcing experiments, suggesting that nonlinear feedbacks are modest. Our models indicate that Greenland is more sensitive than Antarctica to likely atmospheric changes in temperature and precipitation, while Antarctica is more sensitive to increased ice-shelf basal melting. An experiment approximating the Intergovernmental Panel on Climate Change’s RCP8.5 scenario produces additional first-century contributions to sea level of 22.3 and 8.1 cm from Greenland and Antarctica, respectively, with a range among models of 62 and 14 cm, respectively. By 200 years, projections increase to 53.2 and 26.7 cm, respectively, with ranges of 79 and 43 cm. Linear interpolation of the sensitivity results closely approximates these projections, revealing the relative contributions of the individual forcings on the combined volume change and suggesting that total ice-sheet response to complicated forcings over 200 years can be linearized.
The challenge for all photovoltaic technologies is to maximize light absorption, convert photons with minimal losses to electrical charges and efficiently extract them towards the electrical circuit. For thin film silicon solar cells, a compromise must be found as light trapping is usually performed through textured interfaces, that are detrimental to the subsequent growth of dense and high quality silicon layers. We introduce here the concept of smoothening intermediate reflecting layers (IRL), enabling to combine high currents and good electrical quality in Micromorph devices in the superstrate configuration. After exposing the motivation for such structures, we validate the concept by showing a VOCenhancement when employing a polished silicon-oxide-based IRL. Shunting issues and additional reflection losses are pointed out with such technique, highlighting the need to develop alternative techniques for an efficient morphology adaptation before the microcrystalline silicon cell growth.
The clinical and dimensional features associated with suicidal behaviour in bipolar patients during euthymic states are not well characterised.
In a sample of 652 euthymic bipolar patients, we assessed clinical features with the Diagnostic Interview for Genetics Studies (DIGS) and dimensional characteristics with questionnaires measuring impulsivity/hostility and affective lability/intensity. Bipolar patients with and without suicidal behaviour were compared for these clinical and dimensional variables.
Of the 652 subjects, 42.9% had experienced at least one suicide attempt. Lifetime history of suicidal behaviour was associated with being a woman, a history of head injury, tobacco misuse and indicators of severity of bipolar disorder including early age at onset, high number of depressive episodes, positive history of rapid cycling, alcohol misuse and social phobia. Indirect hostility and irritability were dimensional characteristics associated with suicidal behaviour in bipolar patients, whereas impulsivity and affective lability/intensity were not associated with suicidal behaviour.
This study had a retrospective design with no replication sample.
Bipolar patients with earlier onset, mood instability (large number of depressive episodes, rapid cycling) and/or particular addictive and anxiety comorbid disorders might be at high risk of suicidal behaviour. In addition, hostility dimensions (indirect hostility and irritability), may be trait components associated with suicidal behaviour in euthymic bipolar patients.
Lower absorption, lower refractive index and tunable resistance are three advantages of doped silicon oxide containing nanocrystalline silicon grains (nc-SiOx) compared to doped microcrystalline silicon, for the use as p- and n-type layers in thin-film silicon solar cells. In this study we show how optical, electrical and microstructural properties of nc-SiOx layers depend on precursor gas ratios and we propose a growth model to explain the phase separation in such films into Si-rich and O-rich regions as visualized by energy-filtered transmission electron microscopy.
The development of functional-structural plant models has opened interesting perspectives
for a better understanding of plant growth as well as for potential applications in
breeding or decision aid in farm management. Parameterization of such models is however a
difficult issue due to the complexity of the involved biological processes and the
interactions between these processes. The estimation of parameters from experimental data
by inverse methods is thus a crucial step. This paper presents some results and
discussions as first steps towards the construction of a general framework for the
parametric estimation of functional-structural plant models. A general family of models of
Carbon allocation formalized as dynamic systems serves as the basis for our study. An
adaptation of the 2-stage Aitken estimator to this family of model is introduced as well
as its numerical implementation, and applied in two different situations: first a
morphogenetic model of sugar beet growth with simple plant structure, multi-stage and
detailed observations, and second a tree growth model characterized by sparse observations
and strong interactions between functioning and organogenesis. The proposed estimation
method appears robust, easy to adapt to a wide variety of models, and generally provides a
satisfactory goodness-of-fit. However, it does not allow a proper evaluation of estimation
uncertainty. Finally some perspectives opened by the theory of hidden models are
Using a hard exotemplate procedure, hierarchically structured carbonaceous foams have been designed, using silica monolith as inorganic template and phenolic resin as carbon precursor. The open cell carbonaceous monoliths exhibit specific surface areas from 500 to 800 m2.g-1, essentially based on microporosity and macropores ranging from 0.05 up to 50 μm. Application as electrochemical energy storage devices have been checked and discuss inhere.
Tree nuts, peanuts and seeds are nutrient dense foods whose intake has been shown to be associated with reduced risk of some chronic diseases. They are regularly consumed in European diets either as whole, in spreads or from hidden sources (e.g. commercial products). However, little is known about their intake profiles or differences in consumption between European countries or geographic regions. The objective of this study was to analyse the population mean intake and average portion sizes in subjects reporting intake of nuts and seeds consumed as whole, derived from hidden sources or from spreads. Data was obtained from standardised 24-hour dietary recalls collected from 36 994 subjects in 10 different countries that are part of the European Prospective Investigation into Cancer and Nutrition (EPIC). Overall, for nuts and seeds consumed as whole, the percentage of subjects reporting intake on the day of the recall was: tree nuts = 4·4%, peanuts = 2·3% and seeds = 1·3%. The data show a clear northern (Sweden: mean intake = 0·15 g/d, average portion size = 15·1 g/d) to southern (Spain: mean intake = 2·99 g/d, average portion size = 34·7 g/d) European gradient of whole tree nut intake. The three most popular tree nuts were walnuts, almonds and hazelnuts, respectively. In general, tree nuts were more widely consumed than peanuts or seeds. In subjects reporting intake, men consumed a significantly higher average portion size of tree nuts (28·5 v. 23·1 g/d, P<0·01) and peanuts (46·1 v. 35·1 g/d, P<0·01) per day than women. These data may be useful in devising research initiatives and health policy strategies based on the intake of this food group.
Optical properties of GaN templates grown by the Epitaxial Lateral Overgrowth (ELO) technique along the nonpolar (1120) and the semipolar (1122) directions on R- and M-sapphire were investigated. Spatially resolved Cathodoluminescence (CL) was carried out in order to identify defect related transitions, to resolve their localization and to study the efficiency of ELO concerning defect filtration. The wing region of semipolar GaN is shown to be almost defect free with a luminescence spectrum dominated by the GaN emission at 3,472 eV. It is shown that the defect related emissions are localized in the seed, but different defects occur as well in the wing, especially in A-plane (nonpolar) GaN.
The structural and optical properties of InGaN quantum dots grown by plasma-assisted molecular beam epitaxy (MBE) have been characterised using atomic force microscopy, high-resolution transmission electron microscopy (TEM), Z-contrast scanning TEM, micro-photoluminescence (PL), temperature dependent PL and time-resolved PL. The uncapped InGaN nano-islands have densities of ∼1.5 × 1011 cm−2, heights of (1.7 ± 1.0) nm and diameters of (10 ± 4) nm. These parameters are not substantially changed during overgrowth of a GaN cap and the resulting quantum dots have a composition of In0.15Ga0.85N. The observation of narrow luminescence peaks in micro-PL measurements proves light emission from discrete energy states and the optical properties indicate strong confinement of carriers in the quantum dots and an unusually weak impact of piezoelectric field effects.
Facultative paedomorphosis is an environmentally induced polymorphism that results in the coexistence of mature, gilled, and fully aquatic paedomorphic adults and transformed, terrestrial, metamorphic adults in the same population. This polymorphism has been of interest to scientists for decades because it occurs in a large number of caudate amphibian taxa as well as in a large diversity of habitats. Numerous experimental and observational studies have been conducted to explain the proximate and ultimate factors affecting these heterochronic variants in natural populations. The production of each alternative phenotype is based on a genotype×environment interaction and research suggests that differences in the environment can produce paedomorphs through several ontogenetic pathways. No single advantage accounts for the maintenance of this polymorphism. Rather, the interplay of different costs and benefits explains the success of the polyphenism across variable environments. Facultative paedomorphosis allows individuals to cope with habitat variation, to take advantage of environmental heterogeneity in the presence of open niches, and to increase their fitness. This process is expected to constitute a first step towards speciation events, and is also an example of biodiversity at the intraspecific level. The facultative paedomorphosis system is thus ripe for future studies encompassing ecology, evolution, behaviour, endocrinology, physiology, and conservation biology. Few other systems have been broad enough to provide varied research opportunities on topics as diverse as phenotypic plasticity, speciation, mating behaviour, and hormonal regulation of morphology. Further research on facultative paedomorphosis will provide needed insight into these and other important questions facing biologists.
To establish baseline data, using a quantitative motor evaluation protocol, prior to a prospective longitudinal study of the natural history of muscular involvement in myotonic dystrophy (DM).
We conducted a cross-sectional study using a protocol consisting of manual muscle testing (MMT), quantitative muscle testing (QMT), and timed functional testing (TFT) on 50 definite DM patients (27 men, 23 women), aged 16 to 67 years. The relationships between MMT, QMT and TFT scores and disease duration were examined using linear regression analysis.
The muscle weakness was symmetric and the neck flexors and the distal muscles of upper and lower extremities were weaker than proximal muscles. Using MMT scores, the average strength decline was 0.95% per year and was similar for men and women. The strength decline was significantly more rapid for distal muscles than for proximal muscles. Quantitative muscle testing scores documented a strength decline per year of disease duration of 1.2-1.6% for the hip flexors and of 2.0-3.0% for the hand grip flexors.
We observed significant linear relationships between the scores generated by this protocol and disease duration. These data illustrate the distal to proximal progression of muscular involvement in DM, a pattern of progression well-recognized by the clinicians. The follow-up assessment of a large DM cohort in a longitudinal study will establish whether this quantitative protocol provides sensitive measures of the disease progression.