1,611 research outputs found
Lessons learned and unlearned, the theory and practice of employing airpower in small wars, the RAF, 1910 – 2010.
Since the end of The First World War, airpower has been used extensively by some
states in unconventional operations. Surprisingly, very little has been written about
this role of airpower in comparison to conventional operations, both by historians
and theorists, and even more surprisingly by air forces themselves. Historians have
tended to focus on large scale airpower centric events, such as the Battle of Britain,
the strategic bombing campaigns of the Second World War, cold war dog fighting in
Korea etc, while theorists have in the main focused on the strategic level, in
particular the nuclear dimension. Historians for their part have focused on large scale
airpower centric events due to the large quantities of primary source material
available, and also undoubtedly due to the apetite for output related to these well
known events in history. Unsurprisingly air forces have tended to focus their
attention on the ability of airpower to provide an edge over their traditional opponents (i.e. other air forces). This was also a feature of early naval theorists.3
This focus by air forces can be explained due to the need for air foces of all sizes to
justify the heavy investment required by states to maintain a modern, capable air
component. These large budgets can be justified by planning for large scale
conventional conflict against a peer, not so much for countering insurgents in second
and third world countries. In contrast, this work will shine a light on the topic of
airpower in small wars, in particular focusing on the relationship between the theory
and the practice of deploying airpower in small wars and thus look to fill the gap in
historiography, as highlighted above. It will achieve this by focusing on several research areas. Firstly, it will examine the
development of air power theory and doctrine during this period, providing a high
level overview of the entirety of airpower theory, and then focusing specifically on
doctrine and theory relevant to the utilisation of airpower in small wars . Secondly, it
will examine the practical application of air power in small wars during this period,
and throughout it will use organizational learning as an analytical framework to
determine whether or not during this period the RAF can be considered a learning
organisation. By undertanding this a better determination can be made as to the
effectiveness of the RAF in a small wars environment in the past, and its ability to be
succesful in current and future operations. This determination will be based on an
understanding of whether or not theory and doctrine impacted practical application,
and whether lessons learned through practical application impacted subsequent theory and doctrine. The outcome of this research will provide information of
relevance to both the professional and academic fields within this area and will
undoubtedly have policy relevance to air forces and governments around the world.
Furthermore, the focus on organizational learning will have broader appeal as the
outcome will have applicability in several fields and allow organizations of all types
to become more efficient and effective at learning and adapting. The following
section outlines the structure of this work and provides a chapter outline
RX J2115-5840: confirmation of a new near-synchronous polar
Schwope et al (1997) suggested that the newly discovered Polar RX J2115-5840
is a near-synchronous system. We have obtained circular polarisation
observations of RX J2115-5840 which show that the spin and orbital periods
differ by 1.2%. We find the first direct evidence of `pole-switching' in a
near-synchronous Polar. Further our data requires that the accretion flow must
be directed onto the same magnetic field line at all spin-orbit beat phases
implying that at some phases the flow must follow a path around the white dwarf
before accreting.Comment: To be published in Proc Annapolis workshop on magnetic CVs, held in
July 199
Escape rates for Gibbs measures
In this paper we study the asymptotic behaviour of the escape rate of a Gibbs measure supported on a conformal repeller through a small hole. There are additional applications to the convergence of the Hausdorff dimension of the survivor set
Modelling the Marginal Abatement Cost of Mitigating Nitrogen Loss from Agricultural Land
working paperWith the deadline identified by the Water Framework Directive (2000/60/EC)
approaching in 2015 there is increasing pressure on policymakers to introduce new
regulations to achieve water quality targets. Agriculture is one of the contributors of
diffuse pollution entering watercourses and will come under pressure to reduce pollutant
loads. This paper produces Marginal Abatement Cost (MAC) Curves for eight policy
measures that could potentially reduce nitrate leaching from agricultural land on Irish
dairy farms. These include: 1) reduction of fertiliser application by 10%; 2) reduction
of fertiliser application by 20%; 3) livestock unit reduction to limit organic N to 170 kg
ha-1; 4) reduction of livestock units by 20%; 5) change of feed mix to reduce cow
dietary N intake; 6) fencing off watercourses to introduce a buffer zone; 7) improved
dairy cow genetic merit by introducing higher performing dairy breeds; 8) more
efficient slurry application. Results from this study indicate that there will be reductions
in farm gross margins across nearly all policy measures. However, MAC and the
ranking of MAC vary across individual farms and aggregate MAC does not reflect the
heterogeneity of impacts across individual farms. This paper shows that any measure
introduced in a “one size fits all command-control” fashion will not yield efficient
economic results
Scattering, Damping, and Acoustic Oscillations: Simulating the Structure of Dark Matter Halos with Relativistic Force Carriers
We demonstrate that self-interacting dark matter models with interactions
mediated by light particles can have significant deviations in the matter
power-spectrum and detailed structure of galactic halos when compared to a
standard cold dark matter scenario. While these deviations can take the form of
suppression of small scale structure that are in some ways similar to that of
warm dark matter, the self-interacting models have a much wider range of
possible phenomenology. A long-range force in the dark matter can introduce
multiple scales to the initial power spectrum, in the form of dark acoustic
oscillations and an exponential cut-off in the power spectrum. Using
simulations we show that the impact of these scales can remain observationally
relevant up to the present day. Furthermore, the self-interaction can continue
to modify the small-scale structure of the dark matter halos, reducing their
central densities and creating a dark matter core. The resulting phenomenology
is unique to this type of models.Comment: 23 pages, 11 figure
Spatial and temporal distribution of visual information coding in lateral prefrontal cortex
Prefrontal neurons code many kinds of behaviourally relevant visual information. In behaving monkeys, we used a cued target detection task to address coding of objects, behavioural categories and spatial locations, examining the temporal evolution of neural activity across dorsal and ventral regions of the lateral prefrontal cortex (encompassing parts of areas 9, 46, 45A and 8A), and across the two cerebral hemispheres. Within each hemisphere there was little evidence for regional specialisation, with neurons in dorsal and ventral regions showing closely similar patterns of selectivity for objects, categories and locations. For a stimulus in either visual field, however, there was a strong and temporally specific difference in response in the two cerebral hemispheres. In the first part of the visual response (50–250 ms from stimulus onset), processing in each hemisphere was largely restricted to contralateral stimuli, with strong responses to such stimuli, and selectivity for both object and category. Later (300–500 ms), responses to ipsilateral stimuli also appeared, many cells now responding more strongly to ipsilateral than to contralateral stimuli, and many showing selectivity for category. Activity on error trials showed that late activity in both hemispheres reflected the animal's final decision. As information is processed towards a behavioural decision, its encoding spreads to encompass large, bilateral regions of prefrontal cortex
Modelling Integrated Weed Management of an Invasive Shrub in Tropical Australia
1. Most invasive plant species are not well controlled and where biocontrol programs are in place only one third are fully successful. Integrated weed management (IWM) emphasises the use of several complementary control measures. Choosing which combinations will yield control and how biocontrol fits within the strategy requires detailed knowledge of the dynamics of the target and its ecosystem. 2. We used models of increasing complexity to determine which parameters affect site occupancy of an invasive shrub, Mimosa pigra L. in tropical Australia. Two introduced biocontrol agents have spatial effects on both plant fecundity and the probability of recolonisation after senescence. We incorporated biocontrol effects into IWM models with disturbance, mechanical control, herbicide and fire. The models were parameterised from experimental and field data. 3. Models indicate that the reduction in fecundity is not the most important impact of biocontrol; rather it is through defoliation at the edges of stands allowing grasses to out-compete M. pigra seedlings. We demonstrate that biocontrol alone is only successful at low disturbance and seedling survival and even then, current biocontrol agents would take decades to reduce a stand t
Characterisation of mechanochemically synthesised alane (AlH3) nanoparticles
A mechanochemical synthesis process has been used to synthesise alane (AlH3) nanoparticles. The alane is synthesised via a chemical reaction between lithium alanate (LiAlH4) and aluminium chloride (AlCl3) at room temperature within a ball mill and at 77K within a cryogenic mill. The reaction product formed consists of alane nanoparticles embedded within a lithium chloride (LiCl) by-product phase. The LiCl is washed with a solvent resulting in alane nanoparticles which are separated from the by-product phase but are kinetically stabilised by an amorphous particle surface layer. The synthesis of a particular alane structural phase is largely dependent on the milling conditions and two major phases (α, α′) as well as two minor phases (β, γ) have been identified. Ball milling at room temperature can also provide enough energy to allow alane to release hydrogen gas and form aluminium metal nanoparticles. A comparison between XRD and hydrogen desorption results suggest a non-crystalline AlH3 phase is present in the synthesised samples
The Mechanochemical synthesis of magnesium hydride nanoparticles
A mechanochemical method was used to synthesise magnesium hydride nanoparticles with an average crystallite size of 6.7 nm. The use of a reaction buffer was employed as a means of particle size control by restricting agglomeration. Increasing the amount of reaction buffer resulted in a decrease in crystallite size, as determined via X-ray diffraction, and a decrease in particle size, evidenced by transmission electron microscopy
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