Quantum computing with alkaline earth atoms

We present a complete scheme for quantum information processing using the unique features of alkaline earth atoms. We show how two completely independent lattices can be formed for the $^1$S$_0$ and $^3$P$_0$ states, with one used as a storage lattice for qubits encoded on the nuclear spin, and the other as a transport lattice to move qubits and perform gate operations. We discuss how the $^3$P$_2$ level can be used for addressing of individual qubits, and how collisional losses from metastable states can be used to perform gates via a lossy blockade mechanism.Comment: 4 pages, 3 figures, RevTeX

On the convergence of mirror descent beyond stochastic convex programming

In this paper, we examine the convergence of mirror descent in a class of stochastic optimization problems that are not necessarily convex (or even quasi-convex), and which we call variationally coherent. Since the standard technique of "ergodic averaging" offers no tangible benefits beyond convex programming, we focus directly on the algorithm's last generated sample (its "last iterate"), and we show that it converges with probabiility $1$ if the underlying problem is coherent. We further consider a localized version of variational coherence which ensures local convergence of stochastic mirror descent (SMD) with high probability. These results contribute to the landscape of non-convex stochastic optimization by showing that (quasi-)convexity is not essential for convergence to a global minimum: rather, variational coherence, a much weaker requirement, suffices. Finally, building on the above, we reveal an interesting insight regarding the convergence speed of SMD: in problems with sharp minima (such as generic linear programs or concave minimization problems), SMD reaches a minimum point in a finite number of steps (a.s.), even in the presence of persistent gradient noise. This result is to be contrasted with existing black-box convergence rate estimates that are only asymptotic.Comment: 30 pages, 5 figure

Accident Rates, Phase of Operations, and Injury Severity for Solo Students in Pursuit of Private Pilot Certification (1994–2013)

Flight training accidents constitute 14% of general aviation accidents. Herein we determined the rates, injury severity, and phase of flight for primary student solo accidents/incidents (mishaps) in Cessna 172 aircraft. Mishaps over the period spanning 1994–2013 were identified from the NTSB database. Student population data were from the FAA. Statistics employed proportion tests, Poisson distribution, and Mann-Whitney tests. Across the study period, 598 mishaps were identified. While the mishap rate increased nearly two-fold between 1994/1997 and 2002/ 2005, a 35% decline was evident thereafter. Nevertheless, no statistical difference in mishap rates was evident between the initial and current periods. Over 90% of mishaps resulted in no or minor injuries. However, 97% of involved aircraft incurred substantial damage and no incidents were reported. While the percentage of takeoff accidents climbed two-fold, landing accidents accounted for .70% of all mishaps and remained unchanged over the 20 years. Over one-third of landing accidents were related to excess speed. Landing speed computation for a solo flight with an average weight trainee indicated an 11 knot lower V-ref than that for a Cessna 172S at maximum weight. No statistical difference was evident between the two genders for most phases of operation, although females were overrepresented for excess speed landing accidents. Landing accidents, one-third of which relate to excess speed, continue to challenge primary students. The importance of landing speed control, in the context of reduced aircraft weight, should receive additional emphasis in flight instruction

High Capacity Rock Socketed Piles in Scotland, UK

The New Victoria Hospital in Glasgow, Scotland provides a 30,000m² ‘Ambulatory Care and Diagnostic’ (ACAD) facility. The ground conditions beneath the site comprise a variable thickness of Made Ground overlying Glaciomarine Deposits and Glacial Till which in turn rests on the Carboniferous bedrock. However the solid geology is complex and interrupted by a number of faults. The Carboniferous rocks under the site include a number of coal seams, although it is thought that none of these seams has been worked at this location. Due to the relatively low strength of the glacial soils, it was necessary to support the building on piles socketed into the bed rock. However the various coal layers could not be relied upon to provide adequate end bearing capacity and therefore piles were designed to be supported solely on side resistance from the rock socket. In order to investigate pile load bearing capacity and to differentiate end bearing from shaft friction capacity, a number of preliminary and working load tests were carried out with one pile particularly using a’ soft toe’ system. The results of load tests revealed an ultimate shaft friction capacity value in the rock socket of approximately 1.3MPa (189psi)

Predicting Surface Temperatures of Roads: Utilizing a Decaying Average in Forecasting

While being aware of the air temperature during the winter months is very important, many overlook the importance of the road temperature. Knowing the temperature of the road helps transportation departments decide whether or not salt will need to be distributed onto the road, as well as what type of salt. This research was conducted in order to better a forecast model on surface temperature predictions that was shown to be inaccurate. Data was used from the 2013–2014 winter from three cities across Indiana. The data included variables such as air and surface temperatures, precipitation, wind speed, and other variables that could affect the road temperature. These variables were recorded hourly for approximately 5 months. The data was run through both Python and R Studio in order to better visualize and compare the predictions to the observed data. Variables were weighted in different ways to find the variables that contributed most to temperature discrepancies in the forecast. After many tests, the results showed that adding a decaying average over the last 14 days to the predicted temperature yielded the strongest correlation in comparison to the other options available. These results permit additional degrees to be added to our prediction model that will ultimately lead to more accurate predictions, allowing transportation departments to use the predictions to implement in their daily tasks

Dynamics of the digital divide

The digital divide between Indigenous and other Australians describes the unequal access to information and communications technology (ICT) between these groups. Historically, researchers have focused on acquiring new technology, but we argue that it is important to understand all the dynamics of digital usage, including the loss of access to ICT within a household. For long-lived technology such as internet access, it is particularly important to acknowledge that retention of access to the technology needs to be considered. This paper builds on earlier work by exploring the rates of diffusion of ICT for Indigenous Australians using data from the Australian Census Longitudinal Dataset 2006-2011. This dataset allows a longitudinal analysis of changes in internet usage and apparent flows into and out of internet usage for Indigenous and non-Indigenous Australian households. This paper identifies and analyses the important observation that retention of internet access is almost as difficult as acquiring internet access for many Indigenous households (especially in remote areas). While earlier work analyses the digital divide in terms of 'diffusion' or adoption of ICT, this paper shows that retention of internet access is equally important in driving the digital divide. This observation could reflect 'antidiffusion' processes: factors that drive the loss of access to ICT over time. The dynamics of the digital divide have important and ongoing implications for the digital divide and addressing broader socioeconomic disadvantages experienced by Indigenous Australians. Antidiffusion is largely a phenomenon observed among Indigenous people. By analysing loss of access to ICT among both Indigenous and other Australians, we identify several factors that are associated with diffusion and antidiffusion of technology (e.g. household resources, employment, education, the age composition of households). The paper concludes with a discussion of an agenda for future research and potential implications for current policy settings