5,362 research outputs found
Dynamic Phase Transitions in Cell Spreading
We monitored isotropic spreading of mouse embryonic fibroblasts on
fibronectin-coated substrates. Cell adhesion area versus time was measured via
total internal reflection fluorescence microscopy. Spreading proceeds in
well-defined phases. We found a power-law area growth with distinct exponents
a_i in three sequential phases, which we denote basal (a_1=0.4+-0.2), continous
(a_2=1.6+-0.9) and contractile (a_3=0.3+-0.2) spreading. High resolution
differential interference contrast microscopy was used to characterize local
membrane dynamics at the spreading front. Fourier power spectra of membrane
velocity reveal the sudden development of periodic membrane retractions at the
transition from continous to contractile spreading. We propose that the
classification of cell spreading into phases with distinct functional
characteristics and protein activity patterns serves as a paradigm for a
general program of a phase classification of cellular phenotype. Biological
variability is drastically reduced when only the corresponding phases are used
for comparison across species/different cell lines.Comment: 4 pages, 5 figure
Stability constants of aza-oxa-crown ether complexes with silver(I) in nonaqueous polar solvents
Reference Distorted Prices
I show that when consumers (mis)perceive prices relative to reference prices,
budgets turn out to be soft, prices tend to be lower and the average quality of
goods sold decreases. These observations provide explanations for decentralized
purchase decisions, for people being happy with a purchase even when they have
paid their evaluation, and for why trade might affect high quality local firms
'unfairly'
The freshwater crayfish Austropotamobius pallipes in South Tyrol. Heritage species and bioindicator
Rapid decline of crayfish in European freshwaters and continuing threat necessitate integrated actions in conservation and management of native crayfish populations. Besides biological reasons (diseases, plague), the impact of toxic and harmful substances (fertilisers, herbicides) or wastewater effluents, habitat alteration or fragmentation have been responsible for their decline in some regions. The same is true for the region of South Tyrol, where compared to previous investigations, only 10 of a former total of 15 crayfish locations in the water bodies could be affirmed. Although two new populations of the non-indigenous Astacus astacus were detected, the native Austropotamobius pallipes continues to decline. While many investigations have focused accurately on causal coherences for the decline of native populations, the properties of crayfish facilitate to reverse the situation. In a few examples, the potential of Austropotamobius pallipes, the native crayfish in South Tyrol, as “surrogate species” for effective biological conservation is discussed. Given the various adequate attributes of freshwater crayfish as surrogate species (including indicator species, umbrella species and flagship species qualities), they may help to advance not only the crayfish situation itself but also freshwater ecosystem properties in general
After the Standard Model: New Resonances at the LHC
Experiments will soon start taking data at CERN's Large Hadron Collider (LHC)
with high expectations for discovery of new physics phenomena. Indeed, the
LHC's unprecedented center-of-mass energy will allow the experiments to probe
an energy regime where the standard model is known to break down. In this
article, the experiments' capability to observe new resonances in various
channels is reviewed.Comment: Preprint version of a Brief Review for Modern Physics Letters A.
Changes w.r.t. the fully corrected version are smal
Lysine Supplementation of Barley-Soybean Meal Diets for Growing Pigs
The lysine requirement of pigs as suggested by the National Research Council (NRC) was determined using corn-soybean meal based diets. More recent research has indicated that differences exist in the availability of lysine in different ingredients. It has been suggested that lysine in barley is less available than lysine in corn. Thus, it is possible that diets formulated with barley and soybean meal to meet the NRC\u27s suggested lysine requirement, might actually be deficient in this amino acid. This study was conducted to determine the lysine needs of pigs fed barley-soybean meal diets from approximately 45 to 75 lb
Contribution of snowfall from diverse synoptic conditions in the Catskill/Delaware Watershed of New York State
Snowfall in the six basins of the Catskill/Delaware Watershed in south‐central New York State historically contributes roughly 20–30% of the water resources derived from the watershed for use in the New York City water supply. The watershed regularly experiences snowfall from three distinctive weather patterns: coastal mid‐latitude cyclones, overrunning systems, and lake‐effect or Great Lakes enhanced storms. Using synoptic weather classification techniques, these distinct regional atmospheric patterns impacting the watershed are isolated and analysed in conjunction with daily snowfall observations from 1960 to 2009 to allow the influence of each synoptic weather pattern on snowfall to be evaluated independently.
Results indicate that snowfall‐producing events occur on average approximately 63 days/year, or once every 4 days during the October–May season, leading to an average of 213 cm/year of snowfall within the watershed. Snowfall from Great Lakes enhanced storms and overrunning systems contribute nearly equally to seasonal totals, representing 38 and 39%, respectively. Coastal mid‐latitude cyclones, while producing the highest amount of snowfall per event on average, contribute only 16% to the watershed average total snowfall. Predicted climate change is expected to impact snowfall differently depending on the specific atmospheric pattern producing the snow. As such, quantifying the contribution of snowfall to the watershed by synoptic pattern can inform future water management and reservoir operation practices for the New York City Water Supply Management System
Commensurate antiferromagnetic ordering in Ba(Fe{1-x}Co{x})2As2 determined by x-ray resonant magnetic scattering at the Fe K-edge
We describe x-ray resonant magnetic diffraction measurements at the Fe K-edge
of both the parent BaFe2As2 and superconducting Ba(Fe0.953Co0.047)2As2
compounds. From these high-resolution measurements we conclude that the
magnetic structure is commensurate for both compositions. The energy spectrum
of the resonant scattering is in reasonable agreement with theoretical
calculations using the full-potential linear augmented plane wave method with a
local density functional.Comment: 5 pages, 3 figures; accepted for publication in Phys. Rev. B Rapid
Com
Unusual temperature dependence of band dispersion in Ba(Fe(1-x)Ru(x))2As2 and its consequences for antiferromagnetic ordering
We have performed detailed studies of the temperature evolution of the
electronic structure in Ba(Fe(1-x)Ru(x))2As2 using Angle Resolved Photoemission
Spectroscopy (ARPES). Surprisingly, we find that the binding energy of both
hole and electron bands changes significantly with temperature in pure and Ru
substituted samples. The hole and electron pockets are well nested at low
temperature in unsubstituted (BaFe2As2) samples, which likely drives the spin
density wave (SDW) and resulting antiferromagnetic order. Upon warming, this
nesting is degraded as the hole pocket shrinks and the electron pocket expands.
Our results demonstrate that the temperature dependent nesting may play an
important role in driving the antiferromagnetic/paramagnetic phase transition.Comment: 5 pages, 6 figure
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