Investigating the electrical response of the brain of the domestic chicken (Gallus gallus domesticus) to nociception through the use of depth electroencephalography (dEEG) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physiology at Massey University, Manawatū, New Zealand

Nociception is an unavoidable side effect of many routine management and clinical procedures in animals. Electroencephalography (EEG) has previously been used to investigate the effect of nociception on mammalian brain activity. This study aimed to develop a method of assessing the avian response to nociception through depth electroencephalography (dEEG) of brain regions believed to be involved in central pain processing. Two groups of chickens were used in this study to investigate two brain regions, the rostral hyperpallium apicale (HA) and the caudomedial nidopallium (NCM). These regions were chosen due to the afferent and efferent projections they receive from the sensory thalamus and their previous implication in pain processing. Subjects were anaesthetised, and a concentric needle electrode was inserted into the brain to record the electrical activity in response to a number of stimuli. These stimuli included one non-painful, somatosensory stimulus, and four nociceptive stimuli (mechanical, thermal, feather removal and electrical). The dEEG data was then run through a spectral analyser which generated the median frequency (F50), spectral edge frequency (F95) and total power (PTOT). Inspection of these variables determined that within the HA there were two populations of birds, therefore these birds were treated as separate groups in the analysis (hHA and lHA). It was seen that spectral characteristics of the three groups investigated differed significantly, indicating differences in activity and function. The response to stimulation was seen to be significantly different between these brain regions. Following stimulation, the hHA was seen to have a significantly lower percentage of baseline spectral edge frequency and median frequency compared to the NCM and lHA. In response to stimulation the activity of the NCM and lHA remained constant and showed no distinguishable response, while the hHA was more variable. The hHA was much more variable. Although there was no consistent response to stimulation, there was a significant decrease in total power following electrical stimulation in the hHA. This study presents a number of interesting findings and demonstrates that different regions of the brain respond in differing ways to stimulation. The findings suggest that the hyperpallium apicale may respond to nociceptive stimulation, however further work is required to distinguish this. The presence of two populations within the HA group suggests that recordings were taken from two distinct brain regions, one of which displayed comparatively higher sensitivity to nociceptive stimulation. Elucidation of this brain region and further research into the response to nociception is required to further understand the response of the avian brain to pain. For future studies, the development of more precise methods will be required to enable more accurate recording of the activity occurring throughout the avian brain

Are Consumers Disadvantaged or Vulnerable? An Examination of Consumer Complaints to the Better Business Bureau

Questions have emerged recently about the appropriateness of defining disadvantaged consumers based on their membership in certain demographic categories, such as income, age, education, and race. This study assessed whether these traditional classifications are useful for understanding consumer complaining behavior with the Better Business Bureau. Results of analysis of more than 24,000 consumer complaints filed with a local BBB office during a 13-year period do not provide consistent support for this disadvantaged consumer perspective. Instead, the emerging vulnerable consumer perspective may provide a more promising basis for future research

Can the European low-cost airline boom continue?: Implications for regional airports

At a time when the traditional major airlines have struggled to remain viable, the low-cost carriers have become the major success story of the European airline industry. This paper looks behind the headlines to show that although low-cost airlines have achieved much, they too have potential weaknesses and face a number of challenges in the years ahead. The secondary and regional airports that have benefited from low-cost carrier expansion are shown to be vulnerable to future changes in airline economics, government policy and patterns of air service. An analysis of routes from London demonstrates that the low-cost airlines have been more successful in some markets than others. To attractive and historically under-served leisure destinations in Southern Europe they have stimulated dramatic growth and achieved a dominant position. To major hub cities however they typically remain marginal players and to secondary points in Northern Europe their traffic has been largely diverted from existing operators. There is also evidence that the UK market is becoming saturated and new low-cost services are poaching traffic from other low-cost routes. Passenger compensation legislation and possible environmental taxes will hit the low-cost airline industry disproportionately hard. The high elasticities of demand to price in certain markets that these airlines have exploited will operate in reverse. One of the major elements of the low-cost business model involves the use of smaller uncongested airports. These offer faster turn-arounds and lower airport charges. In many cases, local and regional government has been willing to subsidise expansion of air services to assist with economic development or tourism objectives. However, recent court cases against Ryanair now threaten these financial arrangements. The paper also examines the catchment areas for airports with low-cost service. It is shown that as well as stimulating local demand, much traffic is captured from larger markets nearby through the differential in fare levels. This has implications for surface transport, as access to these regional airports often involves long journeys by private car. Consideration is then given to the feasibility of low-cost airlines expanding into the long-haul market or to regional operations with small aircraft. Many of the cost advantages are more muted on intercontinental services – for example, aircraft utilisation is already high and few routes have sufficient local demand without the use of hubbing. Large turbo-prop aircraft such as the DHC Dash 8 400 series offer very good economics compared to regional jets on short to medium sectors where demand is too thin to support a Boeing 737 operation. flybe is using these on certain ‘third level’ routes in Britain and other opportunities are identified in mainland Europe. It is concluded that there are still good growth prospects for low-cost airlines in Europe, especially in France, Italy and some of the new EU member states but rather than growing to dominate the air transport industry, an equilibrium position is likely to be reached. Some regional airports may see their services reduce once the market becomes saturated or the relative competitive position of the major airports and airlines improves.

Editorial

Peer reviewedFinal Accepted Versio

Emission from the Ionized Gaseous Halos of Low Redshift Galaxies and Their Neighbors

Using a sample of nearly half a million galaxies, intersected by over 8 million lines of sight from the Sloan Digital Sky Survey Data Release 12, we extend our previous study of the recombination radiation emitted by the gaseous halos of nearby galaxies. We identify an inflection in the radial profile of the H$\alpha$+N[{\small II}] radial emission profile at a projected radius of $\sim 50$ kpc and suggest that beyond this radius the emission from ionized gas in spatially correlated halos dominates the profile. We confirm that this is a viable hypothesis using results from a highly simplified theoretical treatment in which the dark matter halo distribution from cosmological simulations is straightforwardly populated with gas. Whether we fit the fraction of halo gas in a cooler (T $= 12,000$ K), smooth ($c = 1$) component (0.26 for galaxies with M$_* = 10^{10.88}$ M$_\odot$ and 0.34 for those with M$_* = 10^{10.18}$ M$_\odot$) or take independent values of this fraction from published hydrodynamical simulations (0.19 and 0.38, respectively), this model successfully reproduces the radial location and amplitude of the observed inflection. We also observe that the physical nature of the gaseous halo connects to primary galaxy morphology beyond any relationship to the galaxy's stellar mass and star formation rate. We explore whether the model reproduces behavior related to the central galaxy's stellar mass, star formation rate, and morphology. We find that it is unsuccessful in reproducing the observations at this level of detail and discuss various shortcomings of our simple model that may be responsible.Comment: 10 pages, 8 figures, accepted by Ap

Recording and wear characteristics of 4 and 8 mm helical scan tapes

Performance data of media on helical scan tape systems (4 and 8 mm) is presented and various types of media are compared. All measurements were performed on a standard MediaLogic model ML4500 Tape Evaluator System with a Flash Converter option for time based measurements. The 8 mm tapes are tested on an Exabyte 8200 drive and 4 mm tapes on an Archive Python drive; in both cases, the head transformer is directly connected to a Media Logic Read/Write circuit and test electronics. The drive functions only as a tape transport and its data recover circuits are not used. Signal to Noise, PW 50, Peak Shift and Wear Test data is used to compare the performance of MP (metal particle), BaFe, and metal evaporate (ME). ME tape is the clear winner in magnetic performance but its susceptibility to wear and corrosion, make it less than ideal for data storage

Emission line ratios for the Circumgalactic Medium and the "Bimodal" Nature of Galaxies

We find significantly different diagnostic emission line ratios for the circumgalactic gas associated with galaxies of stellar masses above and below $10^{10.4}$ M$_\odot$ using SDSS spectroscopy. Specifically, in a sample of 17,393 galaxies, intersected by 18,535 lines of sight at projected radii between 10 and 50 kpc, we stack measured fluxes for nebular strong emission lines, [O {\small III}] $\lambda$5007, H$\alpha$ and [N {\small II}] $\lambda6583$, and find that the gas surrounding the lower mass galaxies exhibits similar line ratios to those of gas ionized by star formation and that surrounding the higher mass galaxies similar to those of gas ionized by AGN or shocks. This finding highlights yet another characteristic of galaxies that is distinctly different above and below this stellar mass threshold, but one that is more closely connected to the gas accretion behavior hypothesized to be responsible for this dichotomy.Comment: 5 pages, 3 figures, accepted by ApJ