Summary
African swine fever (ASF) is a highly contagious haemorrhagic disease of pigs that has the potential to cause mortality nearing 100% in naïve animals. While an outbreak of ASF in the United ...States’ pig population (domestic and feral) has never been reported, an introduction of the disease has the potential to cause devastation to the pork industry and food security. During the recovery phase of an outbreak, an antibody detection diagnostic assay would be required to prove freedom of disease within the previously infected zone and eventually nationwide. Animals surviving an ASF infection would be considered carriers and could be identified through the persistence of ASF viral antibodies. These antibodies would demonstrate exposure to the disease and not vaccination, as there is no ASF vaccine available. A well‐established commercial enzyme‐linked immunosorbent assay (ELISA) detects antibodies against ASF virus (ASFV), but the diagnostic specificity of the assay had not been determined using serum samples from the pig population of the United States. This study describes an evaluation of the World Organization for Animal Health (OIE)‐recommended Ingezim PPA COMPAC ELISA using a comprehensive cohort (n = 1791) of samples collected in the United States. The diagnostic specificity of the assay was determined to be 99.4% (95% confidence interval (CI): 98.9, 99.7). The result of this study fills a gap in understanding the performance of the Ingezim PPA COMPAC ELISA in the ASF naïve pig population of the United States.
A large Nd-doped core placed in a microstructure cladding (holey fiber) was pumped with a low-brightness diode laser. The area ratio of the pump radiation on the fiber to the core was larger than 30. ...The fiber length was 38 cm. Butt coupled mirrors formed the laser cavity. The emitted radiation at ? = 1060 nm was single transverse mode, the output power amounted to about 10 mW.
We demonstrate femtosecond pulse operation of a soliton fiber laser at 1.06-mum wavelength. This laser makes use of a single piece of microstructure fiber that has been designed to simultaneously ...provide anomalous dispersion and laser gain. Using a saturable absorber mirror with deep modulation depth to initiate and sustain mode-locking, this fiber provides clean and nearly transform-limited pulses down to a pulse duration of 180 fs. To the best of our knowledge, this constitutes the first demonstration of a pure soliton fiber laser in the neodymium gain band
Out-of-phase supermode with adjacent modes was selected in a multicore fiber (MCF) laser phase-locked by field propagation inside an annular waveguide (AW), which was butt coupled to the MCF. The ...individual emitters (microcores) were placed on a ring with a radius of
131
μm
. The AW had a ring radius of
130
μm
and a ring thickness of
25
μm
. In this all-fiber system the radiation of the circular laser array was directly launched into the guiding ring of the AW. The emitted field distribution was reproduced by constructive multimode interference while propagating over the AW. This realized mutual coherence between the individual microcores. Numerical simulations of the field-propagation in the AW are presented. The influence of the ring thickness as well as the influence of geometrical parameter variations on the phase-locking properties of the system is investigated numerically.
A multicore fiber serving as the gain medium for a fiber laser is introduced. Nearly 40 monomode cores are fitted into a standard multimode silica glass fiber. The cores are arranged on an annulus ...situated near the border of the fiber. The multimode fiber guides the pump radiation with which the Nd
3+-doped cores are excited. The pump waveguide was modelled presupposing that the absorption is nearly homogeneously distributed. The lasing properties of this sophisticated design are quite promising giving about 450 mW at
λ=1050 nm for a pump power (
λ=805 nm) of 1800 mW and a fiber length of 40 cm. The slope efficiency amounts to 40%. The far field intensity pattern possessing an angular width defined by a single source resembles that of an ensemble of emitters with random phases.
The dielectric function of PbS quantum dots (Qdots) with diameters of 3.5-5.0 nm in glass matrix is determined from transmission measurements by Maxwell-Garnett effective medium theory combined with ...iterative Kramers-Kronig analysis. The algorithm used provides real and imaginary part of the dielectric function in the 200-1800 nm spectral range, for both Qdot-doped glasses as well as the PbS Qdots alone. The latter data are compared with the results obtained from colloidal PbS quantum dots and, within the limits of the experimental error, agreement is found.
We demonstrate the generation of ultrabroad spectra in a photonic crystal fiber with a kagome-lattice transverse structure. This two-dimensional periodic photonic lattice allows for strong ...confinement of light without employing defect states nor using photonic bandgap guiding. Light guiding is mediated by total internal reflection in the intersections of the lattice structure, similar to tapered or micro-structured fibers. The kagome lattice structure is manufactured from a soft glass with a high nonlinearity. Using a Ti:sapphire oscillator as a pump source, we observe for the first time impressive supercontinuum generation in the guided modes of a 2D photonic lattice. Supercontinuum generation is caused by fission and radiation of higher-order solitons in the anomalous dispersion range. Our spectrum encompasses the spectral range from 200 to 1750 nm. The dependence of the continuum on coupling spot location, fiber length, and pump wavelength and power as well as on pulse duration and polarization state is investigated. Using a numerical simulation for the lattice structure, pulse propagation through this structure is theoretically studied. Our model reveals the mechanism of supercontinuuum generation in the 2D photonic structure and explains the essential experimental findings.
A novel design for a microstructure fiber (MSF) laser consisting of a large core and a single annulus of 5 air holes is described. The fiber design incorporates a silica core that was doped in the ...liquid phase with 1300 ppm Nd2O3. The light guiding losses in the structurally very simple MSF are approximately 0.7 dB/m. Single transverse mode emission is demonstrated with a mode field area larger than 200 microm2. The laser simultaneously emits at two groups of wavelengths centered at 1060 nm and 1090 nm. Pumped by a cw Ti:sapphire laser, the fiber laser yields a maximum output power of 280 mW (pump power limited) at a slope efficiency of 52%. Our results indicate how the advanced possibilities of MSF's can be used for optimized fiber laser designs.
We investigated the emission behavior of cw diode pumped double clad fiber lasers with and without a semiconductor saturable absorber mirror (SESAM) present. Without the SESAM, we verified that ...cw-pumped multi longitudinal mode lasers start oscillating in a pulsed fashion. Maximizing the emission rate (maximum emission principle C.L. Tang, H. Statz, Maximum emission principle and phase locking in multimode lasers, J. Appl. Phys. 38 (7) (1967) 2963), the lasing system favors a pulsed emission (self-pulsing) over a cw one. Simultaneous oscillation of a large number of modes in homogeneously broadened lasers is not exclusively due to spatial hole burning but due to spontaneous mode locking spanning a certain frequency range regardless of the number of modes contained in this range. Third order nonlinear polarization terms (combination tones) help to equalize non equidistant (dispersion shifted) mode intervals. The combination tones act as seed signals onto which the dispersion shifted mode frequencies lock establishing moreover, at the same time, definite phase relationships between the modes. With the SESAM self pulsing goes over into a self locked mode of emission. The conditions to achieve this type of emission behavior are inferred from the self pulsing state.
The embryo of the grass shrimp, Palaemonetes pugio, is surrounded during development by a protective extracellular coat designated as the embryonic coat (EC). At hatching, this EC is composed of four ...embryonic envelopes (EE), each of which is composed of multiple layers. The outermost layer of the EC, the outer investment coat (OIC), is derived primarily, if not completely, from pleopods of the female. The first envelope (EE1) forms as a bilayered envelope, EE1 a and EE1 b, immediately after oviposition. The OIC becomes closely associated with EE1 and remains in close contact with EE1 until hatching occurs. An additional layer, EE1 c, is added to the inner side of EE1 between 3 and 5 d after oviposition. Three more embryonic envelopes, EE2, EE3, and EE4, are formed between the embryo and EE1 by 7 d after oviposition. Formation of embryonic envelopes continues until 10 d after oviposition; by this time each envelope is morphologically distinct in composition, with "outer" and "inner" sides clearly identifiable. All but the innermost embryonic envelope (EE4) are shed by the embryo about 6 h before hatching. Permeability of the EC during the 12-d incubation period is found to decrease between 0 and 5 d after oviposition, and then increase until hatching. Fluorescently labeled lectins react positively with the OIC, indicating the presence of glucose and N-acetylglucosamine residues. Thus, the palaemonid EC is a dynamic structure throughout embryonic development.
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