Galaxy clustering with photometric surveys using PDF redshift information

Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are $\Delta z=0.1$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.Comment: Matches the MNRAS published version. 19 pages, 19 Figure

Exploring the value of Scotland's environment

Protection of the environment can be regarded as representing a substantial cost to business. However, it is typically considered from the point of view of effect on company profitability, rather than its relative importance to human kind. This paper estimates the value of Scotland's natural environment by applying the methodology developed by Costanza et al (1997a and b) for estimation of the value of the earth's ecosystem services. Ecosystem services provide the vital functions to support life on Earth, such as flows of materials and energy. Since the study's publication, further research has sought to apply this global methodology to a regional and national level (for example Loomis et al, 2000, Farber and Griner, 2000 and Stevens et al, 2000). The value derived for Scotland provides a useful context for understanding the scale and importance of Scotland's natural habitats and it helps to reinforce the message that the environment is central to human welfare (Williams et al, 2003). The valuation of ecosystem services in monetary terms provokes theoretical, practical and philosophical arguments. This paper does not seek to revisit in depth these debates; rather the valuation should be taken as a starting point for setting the importance of Scotland's ecosystems in an interesting perspective. A recent edition of the journal Ecological Economics (Costanza and Farber, 2002) was devoted to considering some of these issues and providing many avenues for further exploration

The Influence of Organization Culture on Aviation Safety – A Case Study of a United States Navy FA-18 Landing Mishap

Aviation safety has improved dramatically in the last 50 years as evidenced by declining mishap rates. Improvements in aviation safety have come about primarily through work on two fronts; mechanical improvements (aircraft and its support systems) and human improvements (human interface, training and process interaction). Safety improvements on the hardware side of aviation have come relatively quickly and continuously, paralleling advances in engineering and science. Today’s aircraft have become extremely reliable machines with redundancy built into every system. Unfortunately, while the overall aviation mishap rate has declined, the percentage of accidents attributed to “human error” has steadily increased. Strides in the human or software side of aviation safety have not kept pace with the mechanical or hardware advances. Most think of “human error” in terms of the individual, be it pilot, controller, or mechanic. A less obvious aspect is the organizational responsibility to aviation safety. Why is one airline or squadron able to maintain a perfect safety record with the same machines and personnel available to other less successful organizations? This thesis will examine a Judge Advocate General (JAG) Investigation (written and conducted by the author) of a Landing Mishap involving a Navy FA-18 Hornet. The mishap is significant because a key causal factor was poor organizational climate. The analysis of real-world mistakes and lessons learned in a “high risk” organization will aid in identifying the warning signs of a failing organization and assist in producing some practical solutions towards improving the safety of any aviation organization

The health state preferences and logistical inconsistencies of New Zealanders: a tale of two tariffs

Notwithstanding the proposed use of Cost-Utility Analysis (CUA) to inform health care priority setting in New Zealand, to date there has been no research into New Zealanders’ valuations of health-related quality of life. This paper reports the results of a study of the health state preferences of adult New Zealanders generated from a postal survey to which 1360 people responded (a 50% response rate). The survey employed a self-completed questionnaire in which a selection of health states were described using the EQ-5D health state classification system and respondents’ valuations were sought using a visual analogue scale (VAS). Close attention is paid to the quality of the data, in particular to the ‘logical inconsistencies’ in respondents’ valuations. Regression analysis is used to interpolate values over the 245 possible EQ-5D states. Two tariffs of health state preferences, arising from contrasting treatments of the logical inconsistencies, are reported.New Zealand, EuroQol, EQ-5D

Styles of Scientific Reasoning: A Cultural Rationale for Science Education?

In this paper, we contend that what to teach about scientific reasoning has been bedeviled by a lack of clarity about the construct. Drawing on the insights emerging from a cognitive history of science, we argue for a conception of scientific reasoning based on six “styles of scientific reasoning.” Each “style” requires its own specific ontological and procedural entities, and invokes its own epistemic values and constructs. Consequently, learning science requires the development of not just content knowledge but, in addition, procedural knowledge, and epistemic knowledge. Previous attempts to develop a coherent account of scientific reasoning have neglected the significance of either procedural knowledge, epistemic knowledge, or both. In contrast, “styles of reasoning” do recognize the need for all three elements of domain-specific knowledge, and the complexity and situated nature of scientific practice. Most importantly, “styles of reasoning” offer science education a means of valorizing the intellectual and cultural contribution that the sciences have made to contemporary thought, an argument that is sorely missing from common rationales for science education. Second, the construct of “styles of reasoning” offers a more coherent conceptual schema for the construct of scientific reasoning—one of the major goals of any education in the sciences

Formulation and Burning Behaviour of Fire Retardant Polyisoprene Rubbers

This research aimed to develop new fire retardant rubber formulations, by surveying the existing knowledge base for fire retardant approaches for polyisoprene rubber, characterising unmodified compounds, formulating and studying fire retarded compounds for use within suspension and anti-vibration mounting systems. Materials have been prepared on a bench scale and evaluated for physical properties. Thermal decomposition has been studied using Thermogravimetric Analysis (TGA) in both air and nitrogen. Burning behaviour has been studied using a horizontal burning rate method, Limiting Oxygen Index (LOI) and the cone calorimeter. Basic rubber mixtures were prepared to investigate the interactions between the polymer and additives, under TGA conditions. Zinc oxide was found to have little effect on the polymer decomposition, while silica reduced thermal stability. When decomposed in air, increasing levels of carbon black reduce the rate of mass loss in the polymer. Comparing formulations with different cross-linking types, sulphur without cross-linking increases the heat release in a cone calorimeter; but when low levels of sulphur form efficient cross-links, heat release is suppressed, as also occurs with organic peroxide cross-linking. The effect of carbon black on burning behaviour was compared with inorganic fillers. Within the cone calorimeter, material containing carbon black formed a char-like residue which provides some reduction in the rate heat release, and did not contribute to the fuel load. The use of inorganic fillers yielded more rapid burning behaviour. Any level of carbon black addition gives a reduction in the rates of heat, smoke, CO, and CO2 release, confirming that carbon black had a stabilising effect. Intumescent formulations were prepared using ammonium polyphosphate (APP), pentaerythritol and melamine, and separately using expandable graphite (EG). Within the cone calorimeter both systems yielded a significant reduction in the first peak of heat release rate, but a much higher second peak than for the unmodified compound. This second peak value is associated with the significant levels of intumescence observed. The use of EG gave a greater level of fire retardance compared to the APP formulation. Hydrated fillers, and blends thereof, were investigated; an equal blend of aluminium hydroxide (ATH) and magnesium hydroxide (MH) was found to yield the lowest peak release rate on the cone calorimeter. Hydrated fillers were investigated with synergists proposed in the literature. Little benefit was noted for these additives when used as partial replacements for the filler