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Production from smallholder owned goats in the semi-arid tropics is constrained by dry season feed shortages. Kid mortality is high and low growth rate of kids weaned at the onset of the dry season delays slaughtering of males and breeding in females. Supplementation with purchased feed is unaffordable so only locally available, probably non-conventional feeds can be considered. In Southern Zimbabwe, the typical natural vegetation in communal grazing areas consists of annual and perennial grasses and trees and shrubs, many of which are Acacia species. In this project tree fruits, from Acacia and other available species were evaluated as dry season protein supplements for goats.
After prolonged exposure to tanniniferous diets, it has been reported that some rumen microorganisms acquire defensive mechanisms against tannins (Brooker et al., 2000) or produce tannin-degrading enzymes. Such rumen microorganisms are said to be “tannin resistant” as their fermentation activity is less inhibited by the presence of tannins in the host’s diet. As acacia pods contain tannins their use as protein supplements for goats in the dry season may require that they be first detannified e.g. by using polyethylene glycol (PEG). However, goats with prior exposure to tanniniferous diets may have developed adaptive mechanisms to deal with tannins. This study, therefore, investigated the need for tannin inactivation in feeds given to ‘adapted’ animals by comparing the effect on the in vitro fermentation of tree pods incubated with and without PEG using rumen fluid from adapted and unadapted goats.
A comparison of two electron microscopy techniques used to determine the polarity of GaN nanowires is presented. The techniques are convergent beam electron diffraction (CBED) in TEM mode and annular bright field (ABF) imaging in aberration corrected STEM mode. Both measurements were made at nominally the same locations on a variety of GaN nanowires. In all cases the two techniques gave the same polarity result. An important aspect of the study was the calibration of the CBED pattern rotation relative to the TEM image. Three different microscopes were used for CBED measurements. For all three instruments there was a substantial rotation of the diffraction pattern (120 or 180°) relative to the image, which, if unaccounted for, would have resulted in incorrect polarity determination. The study also shows that structural defects such as inversion domains can be readily identified by ABF imaging, but may escape identification by CBED. The relative advantages of the two techniques are discussed.
We describe the performance of the Boolardy Engineering Test Array, the prototype for the Australian Square Kilometre Array Pathfinder telescope. Boolardy Engineering Test Array is the first aperture synthesis radio telescope to use phased array feed technology, giving it the ability to electronically form up to nine dual-polarisation beams. We report the methods developed for forming and measuring the beams, and the adaptations that have been made to the traditional calibration and imaging procedures in order to allow BETA to function as a multi-beam aperture synthesis telescope. We describe the commissioning of the instrument and present details of Boolardy Engineering Test Array’s performance: sensitivity, beam characteristics, polarimetric properties, and image quality. We summarise the astronomical science that it has produced and draw lessons from operating Boolardy Engineering Test Array that will be relevant to the commissioning and operation of the final Australian Square Kilometre Array Path telescope.
This paper is an interim report of our inferences about the hydrostatic structure of the Sun, following the first report of the GONG team in Science (Gough et al., 1996). That work confirms that the spherically averaged structure of the Sun is more or less in agreement with current standard solar models. However, there remain some significant deviations which we regard as important clues to the existence of dynamical phenomena which are not taken into account in standard solar modelling.
Flexible copper indium gallium diselenide (CIGS) solar cells on lightweight substrates can deliver high specific powers. Flexible lightweight CIGS solar cells are also primary candidates for building-integrated panels. In all applications, CIGS cells can greatly benefit from the application of broadband and wide-angle AR coating technology. The AR coatings can significantly improve the transmittance of light over the entire CIGS absorption band spectrum. Increased short-circuit current has been observed after integrating AR coated films onto baseline solar panels. NREL’s System Advisor Model (SAM) has predicted up to 14% higher annual power output on AR integrated vertical or building-integrated panels. The combination of lightweight flexible substrates and advanced device designs employing nanostructured optical coatings together have the potential to achieve flexible CIGS modules with enhanced efficiencies and specific power.
The impact of nanostructured broadband antireflection (AR) coatings on solar panel performance has been projected for a broad range of panel tilt angles at various locations. AR coated films have been integrated on test panels and the short-circuit current has been measured for the entire range of panel tilts. The integration of the AR coatings resulted in an increase in short-circuit current of the panels by eliminating front sheet reflection loss for a broad spectrum of light and wide angle of light incidence. The short-circuit current enhancement is 5% for normal light incidence and approximately 20% for off-angle light incidence. The National Renewable Energy Laboratory (NREL) System Advisor Model (SAM) predicts that this AR coating can yield at least 6.5% improvement in solar panel annual power output. The greatest enhancement, approximately 14%, is predicted for vertical panels. The AR coating’s contributions to vertical mount panels and building-integrated solar panels are significant. This nanostructured broadband AR coating thus has the potential to lower the cost per watt of photovoltaic solar energy.
The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0–∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
The present study compared executive dysfunction among children with attention-deficit/hyperactivity disorder (ADHD) after traumatic brain injury (TBI), also called secondary ADHD (S-ADHD), pre-injury ADHD and children with TBI only (i.e., no ADHD). Youth aged 6–16 years admitted for TBI to five trauma centers were enrolled (n=177) and evaluated with a semi-structured psychiatric interview scheduled on three occasions (within 2 weeks of TBI, i.e., baseline assessment for pre-injury status; 6-months and 12-months post-TBI). This permitted the determination of 6- and 12-month post-injury classifications of membership in three mutually exclusive groups (S-ADHD; pre-injury ADHD; TBI-only). Several executive control measures were administered. Unremitted S-ADHD was present in 17/141 (12%) children at the 6-month assessment, and in 14/125 (11%) children at 12-months post-injury. The study found that children with S-ADHD exhibited deficient working memory, attention, and psychomotor speed as compared to children with pre-injury ADHD. Furthermore, the children with S-ADHD and the children with TBI-only were impaired compared to the children with pre-injury ADHD with regard to planning. No group differences related to response inhibition emerged. Age, but not injury severity, gender, or adaptive functioning was related to executive function outcome. Neuropsychological sequelae distinguish among children who develop S-ADHD following TBI and those with TBI only. Moreover, there appears to be a different pattern of executive control performance in those who develop S-ADHD than in children with pre-injury ADHD suggesting that differences exist in the underlying neural mechanisms that define each disorder, underscoring the need to identify targeted treatment interventions. (JINS, 2014, 20, 971–981)
Cell-implant adhesive strength is important for prostheses. In this paper, an investigation is described into the adhesion of bovine chondrocytes to Ti6Al4V-based substrates with different surface roughnesses and compositions. Cells were cultured for 2 or 5 days, to promote adhesion. The ease of cell removal was characterised, using both biochemical (trypsin) and mechanical (accelerated buoyancy and liquid flow) methods. Computational fluid dynamics (CFD) modelling has been used to estimate the shear forces applied to the cells by the liquid flow. A comparison is presented between the ease of cell detachment indicated using these methods, for the three surfaces investigated.
We have grown a variety of isolated GaN nanowires using gas-source molecular beam epitaxy (MBE) and characterized their structural and optical properties. The nanowires have demonstrated a number of promising materials characteristics, including low defect density and high luminescent intensity. Well-separated nanowires formed spontaneously on Si(111) substrates after deposition of a thin AlN buffer layer. Metal catalysts were not used. X-ray diffraction indicates that the c and a lattice parameters are within 0.01 % of the lattice parameters of bulk GaN. Transmission electron microscopy (TEM) revealed the nanowires to be free of dislocations and stacking faults, although a GaN matrix layer growing at the base of the wires was found to have a high density of basal plane stacking faults. The room temperature photoluminescence (PL) intensity compared favorably with a free-standing, thick film of high quality GaN. Several features of the low temperature PL spectra also indicated that the nanowires had few structural defects or chemical impurities. Finally, electrical characterization of dispersed nanowires demonstrated that efficient electrical contacts could be made and that the resistivity of the nanowires was comparable to that of bulk material.
Growth rates from 10 to 38 μm/h were achieved for heteroepitaxial 3C-SiC on Si (100) substrates by using the propane-silane-hydrogen gas chemistry with HCl as a growth additive. A low-pressure horizontal hot-wall CVD reactor was employed to perform the deposition. The growth rate dependences on silane mole fraction, the process pressure and the growth time were determined experimentally. The growth rate dependence on silane mole fraction was found to follow a linear relationship. The 3C-SiC films were characterized by Normaski Optical Microscopy, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Atomic Force Microscopy and X-ray Diffraction. The X-ray rocking curve taken on the (002) diffraction plane displayed a FWHM of 360 arcsec which indicates that the films are monocrystalline.
A method of secondary enrichment is described suitable for the isolation of a wide range of salmonella serotypes from abattoir swabs and polluted river water. The technique does not employ selectively toxic chemicals.
LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30–240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient buffering makes retrospective imaging of explosive short-term events possible. The scientific focus of LOFAR will initially be on four key science projects (KSPs): (i) Detection of the formation of the very first stars and galaxies in the universe during the so-called epoch of reionization by measuring the power spectrum of the neutral hydrogen 21-cm line (Shaver et al. 1999) on the ∼ 5′ scale; (ii) Low-frequency surveys of the sky with of order 108 expected new sources; (iii) All-sky monitoring and detection of transient radio sources such as γ-ray bursts, X-ray binaries, and exo-planets (Farrell et al. 2004); and (iv) Radio detection of ultra-high energy cosmic rays and neutrinos (Falcke & Gorham 2003) allowing for the first time access to particles beyond 1021 eV (Scholten et al. 2006). Apart from the KSPs open access for smaller projects is also planned. Here we give a brief description of the telescope.