7,924 research outputs found
Dimensionality of spin modulations in 1/8-doped lanthanum cuprates from the perspective of NQR and muSR experiments
We investigate the dimensionality of inhomogeneous spin modulation patterns
in the cuprate family of high-temperature superconductors with particular focus
on 1/8-doped lanthanum cuprates. We compare one-dimensional stripe modulation
pattern with two-dimensional checkerboard of spin vortices in the context of
nuclear quadrupole resonance(NQR) and muon spin rotation(muSR) experiments. In
addition, we also consider the third pattern, a two-dimensional superposition
of spin spirals. Overall, we have found that none of the above patterns leads
to a consistent interpretation of the two types of experiments considered.
This, in particular, implies that the spin vortex checkerboard cannot be ruled
out on the basis of available NQR/muSR experimental results.Comment: 6 pages, 2 figure
Telescopic actions
A group action H on X is called "telescopic" if for any finitely presented
group G, there exists a subgroup H' in H such that G is isomorphic to the
fundamental group of X/H'.
We construct examples of telescopic actions on some CAT[-1] spaces, in
particular on 3 and 4-dimensional hyperbolic spaces. As applications we give
new proofs of the following statements:
(1) Aitchison's theorem: Every finitely presented group G can appear as the
fundamental group of M/J, where M is a compact 3-manifold and J is an
involution which has only isolated fixed points;
(2) Taubes' theorem: Every finitely presented group G can appear as the
fundamental group of a compact complex 3-manifold.Comment: +higher dimension
Rapid shifts in Atta cephalotes fungus-garden enzyme activity after a change in fungal substrate (Attini, Formicidae)
Fungus gardens of the basidiomycete Leucocoprinus gongylophorus sustain large colonies of leaf-cutting ants by degrading the plant material collected by the ants. Recent studies have shown that enzyme activity in these gardens is primarily targeted toward starch, proteins and the pectin matrix associated with cell walls, rather than toward structural cell wall components such as cellulose and hemicelluloses. Substrate constituents are also known to be sequentially degraded in different sections of the fungus garden. To test the plasticity in the extracellular expression of fungus-garden enzymes, we measured the changes in enzyme activity after a controlled shift in fungal substrate offered to six laboratory colonies of Atta cephalotes. An ant diet consisting exclusively of grains of parboiled rice rapidly increased the activity of endo-proteinases and some of the pectinases attacking the backbone structure of pectin molecules, relative to a pure diet of bramble leaves, and this happened predominantly in the most recently established top sections of fungus gardens. However, fungus-garden amylase activity did not significantly increase despite the substantial increase in starch availability from the rice diet, relative to the leaf diet controls. Enzyme activity in the older, bottom sections of fungus gardens decreased, indicating a faster processing of the rice substrate compared to the leaf diet. These results suggest that leaf-cutting ant fungus gardens can rapidly adjust enzyme activity to provide a better match with substrate availability and that excess starch that is not protected by cell walls may be digested by the ants rather than by the fungus-garden symbiont
Inherited epidermolysis bullosa
Inherited epidermolysis bullosa (EB) encompasses a number of disorders characterized by recurrent blister formation as the result of structural fragility within the skin and selected other tissues. All types and subtypes of EB are rare; the overall incidence and prevalence of the disease within the United States is approximately 19 per one million live births and 8 per one million population, respectively. Clinical manifestations range widely, from localized blistering of the hands and feet to generalized blistering of the skin and oral cavity, and injury to many internal organs. Each EB subtype is known to arise from mutations within the genes encoding for several different proteins, each of which is intimately involved in the maintenance of keratinocyte structural stability or adhesion of the keratinocyte to the underlying dermis. EB is best diagnosed and subclassified by the collective findings obtained via detailed personal and family history, in concert with the results of immunofluorescence antigenic mapping, transmission electron microscopy, and in some cases, by DNA analysis. Optimal patient management requires a multidisciplinary approach, and revolves around the protection of susceptible tissues against trauma, use of sophisticated wound care dressings, aggressive nutritional support, and early medical or surgical interventions to correct whenever possible the extracutaneous complications. Prognosis varies considerably and is based on both EB subtype and the overall health of the patient
The Stripe 82 1-2 GHz Very Large Array Snapshot Survey: Multiwavelength Counterparts
We have combined spectrosopic and photometric data from the Sloan Digital Sky
Survey (SDSS) with GHz radio observations, conducted as part of the
Stripe 82 GHz Snapshot Survey using the Karl G. Jansky Very Large Array
(VLA), which covers sq degrees, to a flux limit of 88 Jy rms.
Cross-matching the radio source components with optical data via
visual inspection results in a final sample of cross-matched objects,
of which have spectroscopic redshifts and objects have
photometric redshifts. Three previously undiscovered Giant Radio Galaxies
(GRGs) were found during the cross-matching process, which would have been
missed using automated techniques. For the objects with spectroscopy we
separate radio-loud Active Galactic Nuclei (AGN) and star-forming galaxies
(SFGs) using three diagnostics and then further divide our radio-loud AGN into
the HERG and LERG populations. A control matched sample of HERGs and LERGs,
matched on stellar mass, redshift and radio luminosity, reveals that the host
galaxies of LERGs are redder and more concentrated than HERGs. By combining
with near-infrared data, we demonstrate that LERGs also follow a tight
relationship. These results imply the LERG population are hosted by population
of massive, passively evolving early-type galaxies. We go on to show that
HERGs, LERGs, QSOs and star-forming galaxies in our sample all reside in
different regions of a WISE colour-colour diagram. This cross-matched sample
bridges the gap between previous `wide but shallow' and `deep but narrow'
samples and will be useful for a number of future investigations.Comment: 17 pages, 19 figures. Resubmitted to MNRAS after the initial comment
Pelatihan Implementasi Kurikulum 2013 Bagi Guru SD di Kota Semarang
Curriculum 2013 (henceforth: K13) is designed to support students?óÔé¼Ôäó competence in knowledge, skill and attitude. They can be achieved from learning the series of subjects as a continuum supporting to the competence. Providing teachers is one important thing in K13 because they meet a change of teaching methods. They do not only give materials in the head of the class, but also encourage their students to act creatively and make them speak courageously. Training K13 attempts to formalize the teachers?óÔé¼Ôäó mindsets to prepare, conduct, and evaluate learning based on the approach and evaluation of K13 correctly. The approaches offered in this public service include systemic and continuing steps. After training, the teachers get the information on how to apply K13 and how to make a set of teaching curriculum in primary schools (SD/MI) so that they can improve their skills in applying their teaching
Transverse Demagnetization Dynamics of a Unitary Fermi Gas
Understanding the quantum dynamics of strongly interacting fermions is a
problem relevant to diverse forms of matter, including high-temperature
superconductors, neutron stars, and quark-gluon plasma. An appealing benchmark
is offered by cold atomic gases in the unitary limit of strong interactions.
Here we study the dynamics of a transversely magnetized unitary Fermi gas in an
inhomogeneous magnetic field. We observe the demagnetization of the gas, caused
by diffusive spin transport. At low temperatures, the diffusion constant
saturates to the conjectured quantum-mechanical lower bound ,
where is the particle mass. The development of pair correlations,
indicating the transformation of the initially non-interacting gas towards a
unitary spin mixture, is observed by measuring Tan's contact parameter.Comment: 8 pages, 6 figures. Accepted versio
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