947 research outputs found
Abandonment of crop lands leads to different recovery patterns for ant and plant communities in Eastern Europe
Significant proportion of crop lands have been abandoned as management strategies have changed in Central and Eastern Europe in the past decades. The study of insect versus plant communities in such areas could help us understand how these processes take place, and whether these communities return to a semi-natural state maintained by human activities. Amongst insects ants, as ecosystem engineers, are a perfect target group in this respect. We studied epigaeic ant and plant communities of abandoned old-fields in Romania. Contrary to our expectations, the total number of ant species did not increase with time during succession on old-fields contrary to plants, where an increase was registered in the total number. Disturbancetolerant ant species dominated the ant communities throughout the successional gradient, while in the case of plants a transition was found from weed-dominated to semi-natural communities. The diversity of both ant and plant communities increased after the 1-year stage, but the patterns were different. While a return to semi-natural state could be observed in plants during old-field succession, such a definite change did not occur in ants. This might be caused by the landscape context: the lack of connectivity of old-fields to larger natural areas. While plant propagules of semi-natural and natural habitat species can still successfully colonize the old fields even under such conditions, ant colonizers are mainly disturbance-tolerant species typical for agricultural areas, which can be hardly replaced by typical grassland species. Our findings underline the existence of important discrepancies between plant and ant community succession, mostly treated as paralleling each other. This is the first study to handle the effect of abandonment on ant and plant communities simultaneously in Eastern Europe
Automated glycan assembly of galactosylated xyloglucan oligosaccharides and their recognition by plant cell wall glycan-directed antibodies
We report the automated glycan assembly of oligosaccharides related to the plant cell wall hemicellulosic polysaccharide xyloglucan. The synthesis of galactosylated xyloglucan oligosaccharides was enabled by introducing p-methoxybenzyl (PMB) as a temporary protecting group for automated glycan assembly. The generated oligosaccharides were printed as microarrays, and the binding of a collection of xyloglucan-directed monoclonal antibodies (mAbs) to the oligosaccharides was assessed. We also demonstrated that the printed glycans can be further enzymatically modified while appended to the microarray surface by Arabidopsis thaliana xyloglucan xylosyltransferase 2 (AtXXT2)
evidence from cerebrospinal fluid analysis
Background The diagnosis of multiple sclerosis (MS) is currently based solely
on clinical and magnetic resonance imaging features. However,
histopathological studies have revealed four different patterns of lesion
pathology in patients diagnosed with MS, suggesting that MS may be a
pathologically heterogeneous syndrome rather than a single disease entity.
Objective The aim of this study was to investigate whether patients with
pattern I MS differ from patients with pattern II or III MS with regard to
cerebrospinal fluid (CSF) findings, especially with reference to intrathecal
IgG synthesis, which is found in most patients with MS but is frequently
missing in MS mimics such as aquaporin-4-IgG-positive neuromyelitis optica
spectrum disorders and myelin oligodendrocyte glycoprotein-IgG-positive
encephalomyelitis. Methods Findings from 68 lumbar punctures in patients who
underwent brain biopsy as part of their diagnostic work-up and who could be
unequivocally classified as having pattern I, pattern II or pattern III MS
were analysed retrospectively. Results Oligoclonal bands (OCBs) were present
in 88.2% of samples from pattern I MS patients but in only 27% of samples from
patients with pattern II or pattern III MS (P < 0.00004); moreover, OCBs were
present only transiently in some of the latter patients. A polyspecific
intrathecal IgG response to measles, rubella and/or varicella zoster virus
(so-called MRZ reaction) was previously reported in 60â80% of MS patients, but
was absent in all pattern II or III MS patients tested (P < 0.00001 vs.
previous cohorts). In contrast, the albumin CSF/serum ratio (QAlb), a marker
of bloodâCSF barrier function, was more frequently elevated in samples from
pattern II and III MS patients (P < 0.002). Accordingly, QAlb values and
albumin and total protein levels were higher in pattern II and III MS samples
than in pattern I MS samples (P < 0.005, P < 0.009 and P < 0.006,
respectively). Conclusions Patients with pattern II or pattern III MS differ
significantly from patients with pattern I MS as well as from previous,
histologically non-classified MS cohorts with regard to both intrathecal IgG
synthesis and bloodâCSF barrier function. Our findings strongly corroborate
the notion that pattern II and pattern III MS are entities distinct from
pattern I MS
Ground-State Properties of a Rotating Bose-Einstein Condensate with Attractive Interaction
The ground state of a rotating Bose-Einstein condensate with attractive
interaction in a quasi-one-dimensional torus is studied in terms of the ratio
of the mean-field interaction energy per particle to the
single-particle energy-level spacing. The plateaus of quantized circulation are
found to appear if and only if with the lengths of the plateaus
reduced due to hybridization of the condensate over different angular-momentum
states.Comment: 4 pages, 2 figures, Accepted for publication in Physical Reveiw
Letter
Dynamic Aperture Studies for the Transfer Line From FLUTE to cSTART
The compact STorage ring for Accelerator Research and Technology cSTART project will deliver a new KIT accelerator test facility for the application of novel acceleration techniques and diagnostics. The goal is to demonstrate storing an electron beam of a Laser Plasma Accelerator (LPA) in a compact circular accelerator for the first time. Before installing an LPA, the Far-Infrared Linac and Test Experiment (FLUTE) will serve as a full energy injector for the compact storage ring, providing stable bunches with a length down to a few femtoseconds. The transport of the bunches from FLUTE to the cSTART storage ring requires a transfer line which includes horizontal, vertical and coupled deflections which leads to coupling of the dynamics in the two transverse planes. In order to realize ultra-short bunch lengths at the end of the transport line, it relies on special optics which invokes high and negative dispersion. This contribution presents dynamic aperture studies based on six-dimensional tracking through the lattice of the transfer line
Pattern II and pattern III MS are entities distinct from pattern I MS: evidence from cerebrospinal fluid analysis
Background: The diagnosis of multiple sclerosis (MS) is currently based solely on clinical and magnetic resonance imaging features. However, histopathological studies have revealed four different patterns of lesion pathology in patients diagnosed with MS, suggesting that MS may be a pathologically heterogeneous syndrome rather than a single disease entity. Objective: The aim of this study was to investigate whether patients with pattern I MS differ from patients with pattern II or III MS with regard to cerebrospinal fluid (CSF) findings, especially with reference to intrathecal IgG synthesis, which is found in most patients with MS but is frequently missing in MS mimics such as aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein-IgG-positive encephalomyelitis. Methods: Findings from 68 lumbar punctures in patients who underwent brain biopsy as part of their diagnostic work-up and who could be unequivocally classified as having pattern I, pattern II or pattern III MS were analysed retrospectively. Results: Oligoclonal bands (OCBs) were present in 88.2% of samples from pattern I MS patients but in only 27% of samples from patients with pattern II or pattern III MS (PÂ <Â 0.00004); moreover, OCBs were present only transiently in some of the latter patients. A polyspecific intrathecal IgG response to measles, rubella and/or varicella zoster virus (so-called MRZ reaction) was previously reported in 60â80% of MS patients, but was absent in all pattern II or III MS patients tested (PÂ <Â 0.00001 vs. previous cohorts). In contrast, the albumin CSF/serum ratio (QAlb), a marker of bloodâCSF barrier function, was more frequently elevated in samples from pattern II and III MS patients (PÂ <Â 0.002). Accordingly, QAlb values and albumin and total protein levels were higher in pattern II and III MS samples than in pattern I MS samples (PÂ <Â 0.005, PÂ <Â 0.009 and PÂ <Â 0.006, respectively). Conclusions: Patients with pattern II or pattern III MS differ significantly from patients with pattern I MS as well as from previous, histologically non-classified MS cohorts with regard to both intrathecal IgG synthesis and bloodâCSF barrier function. Our findings strongly corroborate the notion that pattern II and pattern III MS are entities distinct from pattern I MS
Two-dimensional loosely and tightly bound solitons in optical lattices and inverted traps
We study the dynamics of nonlinear localized excitations (solitons) in
two-dimensional (2D) Bose-Einstein condensates (BECs) with repulsive
interactions, loaded into an optical lattice (OL), which is combined with an
external parabolic potential. First, we demonstrate analytically that a broad
(loosely bound, LB) soliton state, based on a 2D Bloch function near the edge
of the Brillouin zone (BZ), has a negative effective mass (while the mass of a
localized state is positive near the BZ center). The negative-mass soliton
cannot be held by the usual trap, but it is safely confined by an inverted
parabolic potential (anti-trap). Direct simulations demonstrate that the LB
solitons (including the ones with intrinsic vorticity) are stable and can
freely move on top of the OL. The frequency of elliptic motion of the
LB-soliton's center in the anti-trapping potential is very close to the
analytical prediction which treats the solition as a quasi-particle. In
addition, the LB soliton of the vortex type features real rotation around its
center. We also find an abrupt transition, which occurs with the increase of
the number of atoms, from the negative-mass LB states to tightly bound (TB)
solitons. An estimate demonstrates that, for the zero-vorticity states, the
transition occurs when the number of atoms attains a critical number N=10^3,
while for the vortex the transition takes place at N=5x10^3 atoms. The
positive-mass LB states constructed near the BZ center (including vortices) can
move freely too. The effects predicted for BECs also apply to optical spatial
solitons in bulk photonic crystals.Comment: 17 pages, 12 figure
Moment of Inertia and Superfluidity of a Trapped Bose Gas
The temperature dependence of the moment of inertia of a dilute Bose gas
confined in a harmonic trap is determined. Deviations from the rigid value, due
to the occurrence of Bose-Einstein condensation, reveal the superfluid
behaviour of the system. In the noninteracting gas these deviations become
important at temperatures of the order of . The role of
interactions is also discussed.Comment: 10 pages, REVTEX, 1 figure attached as postscript fil
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