Planters and their Components: Types, attributes, functional requirements, classification and description

Crop Production/Industries, Farm Management,

Samuel Johnson: authority for an age

The following thesis is concerned with Samuel Johnson’s authority both as a personality and as a writer. It is almost impossible to think of Johnson in terms other than those of an authority. The use of Johnsonian aphorisms to clinch an argument, as though they were imbued with inherent legitimacy, is frequent, and throughout the pages of Boswell's Life, which is the organ through which Johnson is most often revealed, his role as an authority, and in particular, a moralist, is stressed. Johnson’s authority is viewed through various aspects of his life. There are chapters on: his life as a social agent, his Dictionary, his Literary Criticism, his troubled religious life and the Rambler Essays which did more to secure him authority in his own age than any other writings. There is a common thread working through all the chapters. It becomes quite clear that the authority which Johnson obtained was based upon his honest acceptance of his own humanity. Though this fact gave his views legitimacy, it often prevented the type of consistency of thought which we feel that we are entitled to from the pen of a serious moralist. It is this strange fact which provides the matter and the interest of this thesis

Habitat complexity and food item size modify the foraging behaviour of a freshwater fish

The functional response describes the relationship between feeding rate and prey density, and is important ecologically as it describes how foraging behaviour may change in response to food availability. The effects of habitat complexity and food item size were experimentally tested on the foraging parameters and functional responses of the freshwater fish roach Rutilus rutilus. Habitat complexity was varied through the manipulation of substrate and turbidity, and food item size was varied by using fishmeal pellets in two sizes. As water turbidity and substrate complexity increased, the reaction distance and consumption rate (per number) significantly decreased. Increased food item size significantly decreased consumption rates (per number) but had no influence on any other foraging parameter. Analysis of the interactions between substrate complexity, turbidity and food item size revealed food item size had the greatest influence on consumption rate (per number). Turbidity had the least effect on all the foraging parameters tested. Across all experiments, the functional responses were best described by the Type II response, a relatively consistent finding for R. rutilus. These outputs reveal that fish foraging behaviours and functional responses are highly context dependent, varying with environmental parameters and the availability of food resources of different sizes

Measurement of throughput variation across a large format volume-phase holographic grating

In this paper, we report measurements of diffraction efficiency and angular dispersion for a large format (~ 25 cm diameter) Volume-Phase Holographic (VPH) grating optimized for near-infrared wavelengths (0.9 ~ 1.8 μm). The aim of this experiment is to see whether optical characteristics vary significantly across the grating. We sampled three positions in the grating aperture with a separation of 5 cm between each. A 2 cm diameter beam is used to illuminate the grating. At each position, throughput and diffraction angle were measured at several wavelengths. It is found that whilst the relationship between diffraction angle and wavelength is nearly he same at the three positions, the throughputs vary by up to ~ 10% from position to position. We explore the origin of the throughput variation by comparing the data with predictions from coupled-wave analysis. We find that it can be explained by a combination of small variations over the grating aperture in gelatin depth and/or refractive index modulation amplitude, and amount of energy loss by internal absorption and/or surface reflection

Ten years of pulling: Ecosystem recovery after long‐term weed management in Garry oak savanna

Ecosystem restoration is the practice of assisting recovery in degraded ecological communities. The aims of restoration are typically broad, involving the reinstatement of composition, structure, function, and resilience to disturbances. One common restoration tactic in degraded urban systems is to control invasive species, relying on passive restoration for further ecosystem‐level recovery. Here, we test whether this is an effective restoration strategy in Garry oak savanna, a highly threatened and ecologically important community in the North American Pacific Northwest. In urban savanna patches surrounding Victoria, British Columbia, community members have been actively removing aggressive invasive exotic species for over a decade. Based on vegetation surveys from 2007, we tested ecosystem changes in structure, composition, and resilience (i.e., functional redundancy and response diversity) across 10 years of varied management levels. We expected higher levels of invasive species management would correspond with improvements to these ecosystem metrics. However, management explained little of the patterns found over the 10‐year‐period. Woody encroachment was a complicated process of native and exotic invasion, while resilience and compositional changes were most closely tied with landscape connectivity. Thus, though invasive species management may prevent further degradation, active restoration strategies after removal are likely required for recovery of the ecosystem

The ‘caged torch procession’: Celebrities, protesters and the 2008 Olympic torch relay in London, Paris and San Francisco

Along with the opening and closing ceremonies, one of the major non-sports events associated with the modern Olympic Games is the torch relay. Although initiated in 1936, the relay has been subject to relatively little academic scrutiny. The events of April 2008 however will have cast a long shadow on the practice. This essay focuses primarily on one week (6–13 April) in the press coverage of the 2008 torch relay as the flame made its way from London to Paris in Europe and then to San Francisco in the USA. It discusses the interpretations offered in the mediated coverage about the relay, the Olympic movement, the host city and the locations where the relay was taking place, and critically analyses the role of agencies, both for and against the Olympics, that framed the ensuing debate

Phenotypic blood glutathione concentration and selenium supplementation interactions on meat colour stability and fatty acid concentrations in Merino lambs

The interaction between blood glutathione (GSH) and supplementation of selenium (Se, 2.5 mg/kg diet) on meat colour and fatty acids concentrations was studied. Forty eight Merino lambs selected for high blood GSH (HGSH) or low GSH (LGSH) concentration were used. They were fed individually with or without Se supplement for 8 weeks. There were interactions (P< 0.05) between GSH and Se on the colour stability (as w630 nm/w580 nm ratio) of m. longissimus (LD), m. semimembranosus (SM) and m. semitendinosus. Without Se supplementation the ratio was higher in HGSH than LGSH group. However, the difference was reduced with Se supplement. Polyunsaturated and n-3 fatty acids in SM and LD were higher in HGSH than in LGSH group (P< 0.05), and did not change with Se supplement. Se supplementation increased Se content in LD (P< 0.001) and the lungs (P< 0.05), but had no influence in the heart

Characterization of the embedded micromechanical device approach to the monolithic integration of MEMS with CMOS

Recently, a great deal of interest has developed in manufacturing processes that allow the monolithic integration of MicroElectroMechanical Systems (MEMS) with driving, controlling, and signal processing electronics. This integration promises to improve the performance of micromechanical devices as well as lower the cost of manufacturing, packaging, and instrumenting these devices by combining the micromechanical devices with a electronic devices in the same manufacturing and packaging process. In order to maintain modularity and overcome some of the manufacturing challenges of the CMOS-first approach to integration, we have developed a MEMS-first process. This process places the micromechanical devices in a shallow trench, planarizes the wafer, and seals the micromechanical devices in the trench. Then, a high-temperature anneal is performed after the devices are embedded in the trench prior to microelectronics processing. This anneal stress-relieves the micromechanical polysilicon and ensures that the subsequent thermal processing associated with fabrication of the microelectronic processing does not adversely affect the mechanical properties of the polysilicon structures. These wafers with the completed, planarized micromechanical devices are then used as starting material for conventional CMOS processes. The circuit yield for the process has exceeded 98%. A description of the integration technology, the refinements to the technology, and wafer-scale parametric measurements of device characteristics is presented. Additionally, the performance of integrated sensing devices built using this technology is presented

Evidence for large superhumps in TX Col and V4742 Sgr

Since the discovery of the largest positive superhump period in TV Col, we have started a program to search for superhumps in CVs with large orbital periods. Here, we summarize preliminary results of TX Col and V4742 Sgr. TX Col is an intermediate polar with a 5.7-h orbital period. V4742 Sgr is a recent nova with no known periods. CCD unfiltered continuous photometry of these 2 objects was carried out during 56 nights in 2002-3. In TX Col, in addition to the orbital period of 5.7 h, we found peaks at 7.1 h and 5.0 h. These are interpreted as positive and negative superhumps correspondingly, although the effects of the quasi-periodic oscillations at about 2 h were not taken into consideration. In the light curve of V4742 Sgr 2 long periods are detected -- 6.1 and 5.4 h as well as a short-term period at 1.6 h. This result suggests that V4742 Sgr is an intermediate polar candidate and a permanent superhump system with a large orbital period (5.4 h) and a superhump period excess of 13 percent. If these results are confirmed, TX Col, V4742 Sgr and TV Col form a group of intermediate polars with extremely large superhump periods. There seems to be now growing evidence that superhumps can occur in intermediate polars with long orbital periods, which is very likely inconsistent with the theoretical prediction that superhumps can only occur in systems with mass ratios below 0.33. Alternatively, if the mass ratio in these systems is nevertheless below the theoretical limit, they should harbour undermassive secondaries and massive white dwarfs, near the Chandrasekhar limit, which would make them excellent candidates for progenitors of supernovae type Ia.Comment: 9 pages, 8 figures, 3 sty files, To appear in the proceedings of IAU JD5, `White Dwarfs: Galactic and Cosmological Probes', eds. Ed Sion, Stephane Vennes and Harry Shipman, Full abstract in pape