Species competition in multispecies grass swards

There is growing interest in establishing highly biodiverse grasslands that are also capable of maintaining high yields. In order to design successful multispecies mixtures it is necessary to know the competitiveness of individual species and how different management regimes affect this. Some species can survive in highly productive pastures, while others need nursing in special mixtures if they are to make a significant contribution to the forage. This is investigated in the ECOSERVE project and has also been studied in the earlier ORGGRASS project

Slow-light enhanced light-matter interactions with applications to gas sensing

Optical gas detection in microsystems is limited by the short micron scale optical path length available. Recently, the concept of slow-light enhanced absorption has been proposed as a route to compensate for the short path length in miniaturized absorption cells. We extend the previous perturbation theory to the case of a Bragg stack infiltrated by a spectrally strongly dispersive gas with a narrow and distinct absorption peak. We show that considerable signal enhancement is possible. As an example, we consider a Bragg stack consisting of PMMA infiltrated by O2. Here, the required optical path length for visible to near-infrared detection (~760 nm) can be reduced by at least a factor of 10^2, making a path length of 1 mm feasible. By using this technique, optical gas detection can potentially be made possible in microsystems

Creamery organization and construction

Nearly two years ago the Iowa Agricultural Experiment station set out to answer a demand from scores of communities for accurate information on when, where, and how creamery associations might be organized with profit and how a satisfactory creamery should be bulit. Since that time, the station has assisted in the organization of different creamery companies and aided in the construction of eight different creamery buildings. The companies represent every type, from individual ownership to regularly incorporated associations and the buildings are of various types and sizes, ranging in cost from less than $2,000 to more than$6,000. Much valuable detailed information was secured which is now published so that it may be of service to other communities which face the question of organizing a creamery association and erecting a creamery building

Lacto

Interest in sour milk drinks has become quite general in recent years through the work and teaching of Metchnikoff, who believes that their use will aid materially in prolonging life and delaying the changes incident to old age. However, most people dislike sour milk and will not use it, so several years ago the writer undertook to prepare sour milk drinks so flavored with fruit juices as to make them more palatable. The dairy section of the Iowa Agricultural Experiment station took up these experiments and produced a frozen sour milk product of the consistency of ice cream and possessing a delicate and agreeable flavor. This frozen product was called “lacto” and as such became widely known, not merely in this country but in other countries as well

Stoichiometry of δ subunit containing GABAA receptors.

Although the stoichiometry of the major synaptic αβγ subunit-containing GABAA receptors has consensus support for 2α:2β:1γ, a clear view of the stoichiometry of extrasynaptic receptors containing δ subunits has remained elusive. Here we examine the subunit stoichiometry of recombinant α4β3δ receptors using a reporter mutation and a functional electrophysiological approach

Photonic crystal resonator integrated in a microfluidic system

We report on a novel optofluidic system consisting of a silica-based 1D photonic crystal, integrated planar waveguides and electrically insulated fluidic channels. An array of pillars in a microfluidic channel designed for electrochromatography is used as a resonator for on-column label-free refractive index detection. The resonator was fabricated in a silicon oxynitride platform, to support electroosmotic flow, and operated at 1.55 microns. Different aqueous solutions of ethanol with refractive indices ranging from n = 1.3330 to 1.3616 were pumped into the column/resonator and the transmission spectra were recorded. Linear shifts of the resonant wavelengths yielded a maximum sensitivity of 480 nm/RIU and a minimum difference of 0.007 RIU was measured

Universality in edge-source diffusion dynamics

We show that in edge-source diffusion dynamics the integrated concentration N(t) has a universal dependence with a characteristic time-scale tau=(A/P)^2 pi/(4D), where D is the diffusion constant while A and P are the cross-sectional area and perimeter of the domain, respectively. For the short-time dynamics we find a universal square-root asymptotic dependence N(t)=N0 sqrt(t/tau) while in the long-time dynamics N(t) saturates exponentially at N0. The exponential saturation is a general feature while the associated coefficients are weakly geometry dependent.Comment: 4 pages including 4 figures. Minor changes. Accepted for PR

Ptychographic X-ray computed tomography of extended colloidal networks in food emulsions

As a main structural level in colloidal food materials, extended colloidal networks are important for texture and rheology. By obtaining the 3D microstructure of the network, macroscopic mechanical properties of the material can be inferred. However, this approach is hampered by the lack of suitable non-destructive 3D imaging techniques with submicron resolution. We present results of quantitative ptychographic X-ray computed tomography applied to a palm kernel oil based oil-in-water emulsion. The measurements were carried out at ambient pressure and temperature. The 3D structure of the extended colloidal network of fat globules was obtained with a resolution of around 300 nm. Through image analysis of the network structure, the fat globule size distribution was computed and compared to previous findings. In further support, the reconstructed electron density values were within 4% of reference values.Comment: 19 pages, 4 figures, to be published in Food Structur

Low-loss criterion and effective area considerations for photonic crystal fibers

We study the class of endlessly single-mode all-silica photonic crystal fibers with a triangular air-hole cladding. We consider the sensibility to longitudinal nonuniformities and the consequences and limitations for realizing low-loss large-mode area photonic crystal fibers. We also discuss the dominating scattering mechanism and experimentally we confirm that both macro and micro-bending can be the limiting factor.Comment: Accepted for Journal of Optics A - Pure and Applied Optic