Wave Chaos in Elastodynamic Cavity Scattering

The exact elastodynamic scattering theory is constructed to describe the spectral properties of two- and more-cylindrical cavity systems, and compared to an elastodynamic generalization of the semi-classical Gutzwiller unstable periodic orbits formulas. In contrast to quantum mechanics, complex periodic orbits associated with the surface Rayleigh waves dominate the low-frequency spectrum, and already the two-cavity system displays chaotic features.Comment: 7 pages, 5 eps figures, latex (with epl.cls

Unchanged thermopower enhancement at the semiconductor-metal transition in correlated FeSb2−x_{2-x}Tex_x

Substitution of Sb in FeSb$_2$ by less than 0.5% of Te induces a transition from a correlated semiconductor to an unconventional metal with large effective charge carrier mass $m^*$. Spanning the entire range of the semiconductor-metal crossover, we observed an almost constant enhancement of the measured thermopower compared to that estimated by the classical theory of electron diffusion. Using the latter for a quantitative description one has to employ an enhancement factor of 10-30. Our observations point to the importance of electron-electron correlations in the thermal transport of FeSb$_2$, and suggest a route to design thermoelectric materials for cryogenic applications.Comment: 3 pages, 3 figures, accepted for publication in Appl. Phys. Lett. (2011

Strongly aligned molecules inside helium droplets in the near-adiabatic regime

Iodine (I$_2$) molecules embedded in He nanodroplets are aligned by a 160 ps long laser pulse. The highest degree of alignment, occurring at the peak of the pulse and quantified by $\langle \cos^2 \theta_{2D} \rangle$, is measured as a function of the laser intensity. The results are well described by $\langle \cos^2 \theta_{2D} \rangle$ calculated for a gas of isolated molecules each with an effective rotational constant of 0.6 times the gas-phase value, and at a temperature of 0.4 K. Theoretical analysis using the angulon quasiparticle to describe rotating molecules in superfluid helium rationalizes why the alignment mechanism is similar to that of isolated molecules with an effective rotational constant. A major advantage of molecules in He droplets is that their 0.4 K temperature leads to stronger alignment than what can generally be achieved for gas phase molecules -- here demonstrated by a direct comparison of the droplet results to measurements on a $\sim$ 1 K supersonic beam of isolated molecules. This point is further illustrated for more complex system by measurements on 1,4-diiodobenzene and 1,4-dibromobenzene. For all three molecular species studied the highest values of $\langle \cos^2 \theta_{2D} \rangle$ achieved in He droplets exceed 0.96.Comment: 11 pages, 8 figure

Anaerobic co-digestion of agricultural by-products with manure, for enhanced biogas production

Biogas is extensively promoted as a promising renewable energy. Therefore, the search of appropriate co-substrates has come into focus. In this study, we examined the potential of using agricultural byproducts as alternative co-substrates for increased biogas production. The biochemical methane potential (BMP) of six agricultural organic byproducts were tested. Consecutively, the byproduct with the highest BMP was used as a co-digestion substrate with manure, in a continuous stirred tank reactor (CSTR). Meadow grass had the highest BMP value [388 ± 30 NmL of CH₄ g^–1 of volatile solids (VS)] among all mono-substrates tested. On the basis of BMP, the substrates ranked as follows: meadow grass > spring barley, winter wheat, winter barley, ryegrass > rapeseed > manure. Co-digestion of manure with byproducts resulted in only an additive and not synergistic methane production. Continuous co-digestion of 34 g L^–1 raw meadow grass with manure increased the methane production rate of the CSTR reactor by 114% compared to the manure alone

Observation of Periodic Orbits on Curved Two - dimensional Geometries

We measure elastomechanical spectra for a family of thin shells. We show that these spectra can be described by a "semiclassical" trace formula comprising periodic orbits on geodesics, with the periods of these orbits consistent with those extracted from experiment. The influence of periodic orbits on spectra in the case of two-dimensional curved geometries is thereby demonstrated, where the parameter corresponding to Planck's constant in quantum systems involves the wave number and the curvature radius. We use these findings to explain the marked clustering of levels when the shell is hemispherical

Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae

<p>Abstract</p> <p>Background</p> <p>Yeast surface display is a technique, where the proteins of interest are expressed as fusions with yeast surface proteins and thus remain attached to the yeast cell wall after expression. Our purpose was to study whether allergens expressed on the cell surface of baker's yeast <it>Saccharomyces cerevisiae </it>preserve their native allergenic properties and whether the yeast native surface glycoproteins interfere with IgE binding. We chose to use the major allergens from the common wasp <it>Vespula vulgaris </it>venom: phospholipase A1, hyaluronidase and antigen 5 as the model.</p> <p>Results</p> <p>The proteins were expressed on the surface as fusions with a-agglutinin complex protein AGA2. The expression was confirmed by fluorescent cytometry (FACS) after staining the cells with antibody against a C-tag attached to the C-terminal end of the allergens. Phospholipase A1 and hyaluronidase retained their enzymatic activities. Phospholipase A1 severely inhibited the growth of the yeast cells. Antigen 5 - expressing yeast cells bound IgE antibodies from wasp venom allergic patient sera but not from control sera as demonstrated by FACS. Moreover, antigen 5 - expressing yeast cells were capable of mediating allergen-specific histamine release from human basophils.</p> <p>Conclusions</p> <p>All the three major wasp venom allergens were expressed on the yeast surface. A high-level expression, which was observed only for antigen 5, was needed for detection of IgE binding by FACS and for induction of histamine release. The non-modified <it>S. cerevisiae </it>cells did not cause any unspecific reaction in FACS or histamine release assay despite the expression of high-mannose oligosaccharides.</p> <p>In perspective the yeast surface display may be used for allergen discovery from cDNA libraries and possibly for sublingual immunotherapy as the cells can serve as good adjuvant and can be produced in large amounts at a low price.</p

Typologier

TypologiesBy Steffen M. SøndergaardTypologies are needed because they relate the local expression to a greater context and create a general view of the process of evolution. Typologies are therefore needed in establishing the basis of a qualified restoration.Transverse partitioned plan arrangementsIn a number of town gable houses from the 16th century the dwelling fundamentally included two rooms separated by a transverse wall. The residents lived in the rear room with the open fire-place, whereas the front room might have a more out-turned function as a shop or workshop. A best room might be added to the rear room.Longitudinal partitioned plan arrangementsIn (North) Slesvig plan arrangements in town houses existed with a longitudinal partition of the front part of the building: On one side was the long hallway, on the other side the living-room and behind that the kitchen.A best room composed the rear part of the big buildings and now and then there was a third part of the building. The big gable houses built in Ribe after the great fire in 1580 were disposed according to this plan arrangement. Besides longitudinal partitioned plan arrangements – with several and more specialized rooms – gradually displaced transverse partitioned plan arrangements during the 18th century. In farm-houses in (North) Slesvig a similar development took place from transverse partitioned plan arrangements with few and larger rooms into longitudinal partitioned plan arrangements with several and more specialized rooms. From this development I am trying to explain why the dwelling in about ten houses in Sonderho on the wadden-sea island Fano have been enlarged with about two feet width: Nearly all houses in Sonderho are placed with the gables in the east and west and the mentioned enlargement is always made in the north side of the house. These houses have had dwelling and stable under the same roof, separated by a hallway, the socalled »frangel« and now appear with two rows of rooms in the dwelling, separated by a longitudinal partition. The enlargement is documented by added ends of beams and a consequent asymmetrical cross section of the dwelling. Fire insurance documents inform that all these enlargements were half-timbered, and as the change from half-timbering to brick-building in Sonderho takes place about 1800, these enlargements must have been made earlier. The age of the houses however is unknown. Referring to the development mentioned above from few and larger rooms in transverse partitioned plan arrangements to several and smaller rooms in longitudinal partitioned plan arrangements in town houses it is my theory, that these houses have undergone a similar change of the dwelling – but the old, narrow houses have had to be enlarged to be able to contain two rows of rooms.Roof-supporting constructions of timberTraditional constructions are mainly half-timbering and brick-building. In the western part of (North) Slesvig we find a number of farm-houses that seem brick-built, but in these houses the top plate with the beams and the weight of the roof is not placed on the outer wall but is supported by wooden posts in every bay or in every second or third bay – wherefore the top plate can be rather big. The outer wall therefore has no supporting function, but is merely a shade. During the latest 15 years I have registered several of these buildings, and none of these seem to be built later than mid 18th century. The reason for this construction may be the threat of flood-wawes in this area and the possibility of rescue if the timber-construction remained standing when the walls were swept away by the flood