9,103 research outputs found
The military and administrative reforms of the emperor Gallienus
The military and administrative reforms of Gallienus affected the tactical organisation of the army, the composition and structure of the officer corps, and the social composition of the provincial administration. Gallienus' tactical reforms created a powerful body of cavalry, which represented the culmination to a century of increasing mobility and depth in defence. This "battlecavalry" was not the direct ancestor of the later comitatenses. but its tactical value and elite status paved the way for a "dual" system of defence involving frontier garrisons and centralised field-armies. His reforms of the officer corps involved the replacement of senatorial officers by equestrians, and the introduction of the protectorate. He hoped thereby to bind military commanders more closely to himself. The administrative reforms involved increasing the number of equestrian governors. Though senatorial governorships continued to occur, senators were henceforth without any real military power. Whether Gallienus ever issued an "edict" to this effect is uncertain, as is the motive behind the reform. Most scholars see in it an attempt to improve the quality of military leadership, but there is little evidence for this. It is preferable to agree with Aurelius Victor, that Gallienus feared the senators, and so deprived them of their commands. Together, Gallienus' creation of the "battlecavalry" and his reforms of the officer corps and provincial administration created the pre-conditions for the recovery of the Roman empire under the Illyrian emperors, and laid the foundations to the "Military Monarchy" of the later Roman empire
The exploration of body-worn video to accelerate the decision-making skills of police officers within an experiential learning environment
Previous research has highlighted benefits of body-worn video (BWV) to support the work of police officers. The daily demands of policing require officers to make highly pressurized decisions (with associated rapid action) in unpredictable changing environments. It is important that new officers learn techniques of decision-making in a safe and controlled way, which minimizes the risk and harm to all parties while at the same time facilitating effective learning. While the benefits of experiential and immersive learning characterized by active participation have long been used in related professional disciplines, the application to police education has been under-explored. BWV can be used to identify decision-making cues from the environment and nurture pattern recognition, essential to the development of mental models within the officer’s decision-making process. The article will therefore explore the application of BWV in the context of experiential immersive learning to accelerate police officers’ decision-making
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
On a Conjecture of Goriely for the Speed of Fronts of the Reaction--Diffusion Equation
In a recent paper Goriely considers the one--dimensional scalar
reaction--diffusion equation with a polynomial reaction
term and conjectures the existence of a relation between a global
resonance of the hamiltonian system and the asymptotic
speed of propagation of fronts of the reaction diffusion equation. Based on
this conjecture an explicit expression for the speed of the front is given. We
give a counterexample to this conjecture and conclude that additional
restrictions should be placed on the reaction terms for which it may hold.Comment: 9 pages Revtex plus 4 postcript figure
High fidelity transport of trapped-ion qubits through an X-junction trap array
We report reliable transport of 9Be+ ions through a 2-D trap array that
includes a separate loading/reservoir zone and an "X-junction". During
transport the ion's kinetic energy in its local well increases by only a few
motional quanta and internal-state coherences are preserved. We also examine
two sources of energy gain during transport: a particular radio-frequency (RF)
noise heating mechanism and digital sampling noise. Such studies are important
to achieve scaling in a trapped-ion quantum information processor.Comment: 4 pages, 3 figures Updated to reduce manuscript to four pages. Some
non-essential information was removed, including some waveform information
and more detailed information on the tra
Corrugated Silicon Platelet Feed Horn Array for CMB Polarimetry at 150 GHz
Next generation cosmic microwave background (CMB) polarization anisotropy
measurements will feature focal plane arrays with more than 600 millimeter-wave
detectors. We make use of high-resolution photolithography and wafer-scale etch
tools to build planar arrays of corrugated platelet feeds in silicon with
highly symmetric beams, low cross-polarization and low side lobes. A compact
Au-plated corrugated Si feed designed for 150 GHz operation exhibited
performance equivalent to that of electroformed feeds: ~-0.2 dB insertion loss,
<-20 dB return loss from 120 GHz to 170 GHz, <-25 dB side lobes and <-23 dB
cross-polarization. We are currently fabricating a 50 mm diameter array with 84
horns consisting of 33 Si platelets as a prototype for the SPTpol and ACTpol
telescopes. Our fabrication facilities permit arrays up to 150 mm in diameter.Comment: 12 pages; SPIE proceedings for Millimeter, Submillimeter, and
Far-Infrared Detectors and Instrumentation for Astronomy V (Conference 7741,
June 2010, San Diego, CA, USA
Repair of Failing Spirit Lake Outlet Tunnel at Mount St. Helens
The 18 May 1980 eruption of Mount St. Helens resulted in one of the largest debris avalanches recorded in history. The debris avalanche blocked the natural outlet of Spirit Lake. To prevent an uncontrolled and catastrophic lake break-out, the U.S. Army Corps of Engineers (USACE) constructed the Spirit Lake Outlet Tunnel from 1984 to 1985. Because Spirit Lake is located in the Mount St. Helens National Volcanic Monument, the project was transferred to the U.S. Forest Service (USFS) for ownership and management. During original tunnel construction, the most difficulty occurred within the 90-m-wide Julie and Kathy L. shear zone complex. In 1996, tunnel walls within this complex experienced significant convergence, which required major repair along a 30 m segment. During inspections in 2014 and 2015, a 10 m segment at the upstream end of the complex, which had experienced slow heave in the past, was observed to have experienced an increase in heave of approximately 0.6 m, which decreased the hydraulic capacity of the tunnel below acceptable limits. The USACE, in accordance with and with funding from the USFS, designed a repair based on the rib set-shotcrete support system that was used for the 1996 repair. In addition to removing and arresting the heave, the 2015 repair was sized to be compatible with a future potential rehabilitation involving stabilizing and re-grading the invert profile of the Julie and Kathy L. shear zone complex. The 2015 repair construction contract was awarded in September 2015 for $3 million
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