1,865 research outputs found
Comment on "Regularizing capacity of metabolic networks"
In a recent paper, Marr, Muller-Linow and Hutt [Phys. Rev. E 75, 041917
(2007)] investigate an artificial dynamic system on metabolic networks. They
find a less complex time evolution of this dynamic system in real networks,
compared to networks of reference models. The authors argue that this suggests
that metabolic network structure is a major factor behind the stability of
biochemical steady states. We reanalyze the same kind of data using a dynamic
system modeling actual reaction kinetics. The conclusions about stability, from
our analysis, are inconsistent with those of Marr et al. We argue that this
issue calls for a more detailed type of modeling
Ice thickness measurements and volume estimates for glaciers in Norway
Glacier volume and ice thickness distribution are important variables for water resource management in Norway and the assessment of future glacier changes. We present a detailed assessment of thickness distribution and total glacier volume for mainland Norway based on data and modelling. Glacier outlines from a Landsat-derived inventory from 1999 to 2006 covering an area of 2692 ± 81 km² were used as input. We compiled a rich set of ice thickness observations collected over the past 30 years. Altogether, interpolated ice thickness measurements were available for 870 km² (32%) of the current glacier area of Norway, with a total ice volume of 134 ± 23 km³. Results indicate that mean ice thickness is similar for all larger ice caps, and weakly correlates with their total area. Ice thickness data were used to calibrate a physically based distributed model for estimating the ice thickness of unmeasured glaciers. The results were also used to calibrate volume–area scaling relations. The calibrated total volume estimates for all Norwegian glaciers ranged from 257 to 300 km³
Investigating the Effect of Stratospheric Radiation on Seed Germination and Growth
Three seed types: bean (Phaseolus vulgaris), corn (Zea mays) and radish (Raphanus sativus) were flown in a high altitude weather balloon into the mid-stratosphere to investigate the effects of high altitude radiation on germination success and seedling growth. After recovering and planting the seeds, the bean seeds showed lower germination success with exposure to high altitude radiation, and consequently stunted seedling growth. Cord and radish seeds experienced a statistically significant positive effect on germination success form radiation exposure compared to control seeds, but negative effect on seedling growth. Overall, the field experiments presented here support laboratory studies that show radiation exposure on vegetable seeds has a mixed effect on the germination success and negative effect on seedling growth on investigated seed types
Clinical and functional characterisation of a novel TNFRSF1A c.605T > A/V173D cleavage site mutation associated with tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), cardiovascular complications and excellent response to etanercept treatment.
Objectives: To study the clinical outcome, treatment
response, T-cell subsets and functional consequences of a
novel tumour necrosis factor (TNF) receptor type 1
(TNFRSF1A) mutation affecting the receptor
cleavage site.
Methods: Patients with symptoms suggestive of tumour
necrosis factor receptor-associated periodic syndrome
(TRAPS) and 22 healthy controls (HC) were screened for
mutations in the TNFRSF1A gene. Soluble TNFRSF1A and
inflammatory cytokines were measured by ELISAs.
TNFRSF1A shedding was examined by stimulation of
peripheral blood mononuclear cells (PBMCs) with phorbol
12-myristate 13-acetate followed by flow cytometric
analysis (FACS). Apoptosis of PBMCs was studied by
stimulation with TNFa in the presence of cycloheximide
and annexin V staining. T cell phenotypes were monitored
by FACS.
Results: TNFRSF1A sequencing disclosed a novel V173D/
p.Val202Asp substitution encoded by exon 6 in one
family, the c.194–14G.A splice variant in another and
the R92Q/p.Arg121Gln substitution in two families.
Cardiovascular complications (lethal heart attack and
peripheral arterial thrombosis) developed in two V173D
patients. Subsequent etanercept treatment of the V173D
carriers was highly effective over an 18-month follow-up
period. Serum TNFRSF1A levels did not differ between
TRAPS patients and HC, while TNFRSF1A cleavage from
monocytes was significantly reduced in V173D and R92Q
patients. TNFa-induced apoptosis of PBMCs and T-cell
senescence were comparable between V173D patients
and HC.
Conclusions: The TNFRSF1A V173D cleavage site
mutation may be associated with an increased risk for
cardiovascular complications and shows a strong
response to etanercept. T-cell senescence does not seem
to have a pathogenetic role in affected patients
First report of bacterial spot caused by Xanthomonas cucurbitae on pumpkin in Italy
In 2018, a disease outbreak was observed on pumpkin (Cucurbita moschata cv. Violina) in the municipality of Reggio Emilia (Northern Italy). Symptoms were observed on leaves and fruits
Modelling the future evolution of glaciers in the European Alps under the EURO-CORDEX RCM ensemble
Glaciers in the European Alps play an important role in
the hydrological cycle, act as a source for hydroelectricity and have a
large touristic importance. The future evolution of these glaciers is driven
by surface mass balance and ice flow processes, of which the latter is to
date not included explicitly in regional glacier projections for the Alps.
Here, we model the future evolution of glaciers in the European Alps with
GloGEMflow, an extended version of the Global Glacier Evolution Model (GloGEM),
in which both surface mass balance and ice flow are explicitly
accounted for. The mass balance model is calibrated with glacier-specific
geodetic mass balances and forced with high-resolution regional climate
model (RCM) simulations from the EURO-CORDEX ensemble. The evolution of the
total glacier volume in the coming decades is relatively similar under the
various representative concentrations pathways (RCP2.6, 4.5 and 8.5), with
volume losses of about 47 %–52 % in 2050 with respect to 2017. We find that
under RCP2.6, the ice loss in the second part of the 21st century is
relatively limited and that about one-third (36.8 % ± 11.1 %,
multi-model mean ±1σ) of the present-day (2017) ice volume
will still be present in 2100. Under a strong warming (RCP8.5) the future
evolution of the glaciers is dictated by a substantial increase in surface
melt, and glaciers are projected to largely disappear by 2100 (94.4±4.4 %
volume loss vs. 2017). For a given RCP, differences in future
changes are mainly determined by the driving global climate model (GCM),
rather than by the RCM, and these differences are larger than those arising
from various model parameters (e.g. flow parameters and cross-section
parameterisation). We find that under a limited warming, the inclusion of
ice dynamics reduces the projected mass loss and that this effect increases
with the glacier elevation range, implying that the inclusion of ice
dynamics is likely to be important for global glacier evolution projections.</p
NNLO QCD corrections to event orientation in e+e- annihilation
We present a new implementation of the NNLO QCD corrections to three-jet final states and related event-shape observables in electron–positron annihilation. Our implementation is based on the antenna subtraction method, and is performed in the NNLOjet framework. The calculation improves upon earlier results by taking into account the full kinematical information on the initial state momenta, thereby allowing the event orientation to be computed to NNLO accuracy. We find the event-orientation distributions at LEP and SLC to be very robust under higher order QCD corrections
Constraining regional glacier reconstructions using past ice thickness of deglaciating areas – a case study in the European Alps
In order to assess future glacier evolution and
meltwater runoff, accurate knowledge on the volume and the ice thickness
distribution of glaciers is crucial. However, in situ observations of
glacier thickness are sparse in many regions worldwide due to the difficulty
of undertaking field surveys. This lack of in situ measurements can be
partially overcome by remote-sensing information. Multi-temporal and
contemporaneous data on glacier extent and surface elevation provide past
information on ice thickness for retreating glaciers in the newly
deglacierized regions. However, these observations are concentrated near the
glacier snouts, which is disadvantageous because it is known to introduce
biases in ice thickness reconstruction approaches. Here, we show a strategy
to overcome this generic limitation of so-called retreat thickness
observations by applying an empirical relationship between the ice viscosity
at locations with in situ observations and observations from digital elevation model (DEM) differencing at the glacier margins. Various datasets from the European
Alps are combined to model the ice thickness distribution of Alpine glaciers
for two time steps (1970 and 2003) based on the observed thickness in regions
uncovered from ice during the study period. Our results show that the
average ice thickness would be substantially underestimated (∼ 40 %) when relying solely on thickness observations from previously
glacierized areas. Thus, a transferable topography-based viscosity scaling
is developed to correct the modelled ice thickness distribution. It is shown
that the presented approach is able to reproduce region-wide glacier
volumes, although larger uncertainties remain at a local scale, and thus might
represent a powerful tool for application in regions with sparse
observations.</p
Grapevine fanleaf virus detection in various grapevine organs using polyclonal and monoclonal antibodies
Monoclonal antibodies prepared with grapevine fanleaf virus (GFV) are useful for detecting the virus in plant extracts. In this paper we describe comparisons between different ELISA techniques using rabbit and chicken immunoglobulins as weil as monoclonal antibodies (MCA). The technique using chicken immunoglobulins for coating the plates followed by MCA and goat anti-mouse phosphatase conjugate was the best one for detecting GFV in plant sap. In this technique, ascitic fluids containing MCA could be diluted up to 10-6. Our experiments clearly demonstrate that the detection of GFV is possible in grapevine not only from leaves or rootlets, but also from wood shavings, without grinding them. We replaced the classical nicotine containing extraction medium by a harmless phosphate or Tris-HCl buffer. To detect GFV with these media it is essential that the buffer should contain polyvinylpyrrolidone and that its molarity should not be less than 0.1 M
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