SECURING AMERICA’S CAPITAL

The concrete barriers, sewer pipes, and chain-link fencing that prompted the National Capital Planning Commission’s security efforts inconvenienced city residents, workers, and visitors and degraded the appearance of one of the most carefully designed and naturally beautiful cities in the world. And yet, what made these barriers intolerable was their underlying message—that the nation’s capital would allow terrorists to limit the American hallmark of open access. The National Capital Planning Commission does not ask federal agencies to ignore the threat reality, but it does ask that agencies cease to install monuments of fear and retrenchment. As the capital’s watchful steward, the Commission is committed to preserving urban design ideals and cultivating Washington’s two-hundredyear-old planning tradition

Examining the Role of Environment in a Comprehensive Sample of Compact Groups

(Abridged) Compact groups, with their high number densities, small velocity dispersions, and an interstellar medium that has not been fully processed, provide a local analog to conditions of galaxy interactions in the earlier universe. The frequent and prolonged gravitational encounters that occur in compact groups affect the evolution of the constituent galaxies in a myriad of ways, for example gas processing and star formation. Recently, a statistically significant "gap" has been discovered mid-infrared IRAC colorspace of compact group galaxies. This gap is not seen in field samples and is a new example of how the compact group environment may affect the evolution of member galaxies. In order to investigate the origin and nature of this gap, we have compiled a sample of 49 compact groups. We find that a statistically significant deficit of galaxies in this gap region of IRAC colorspace is persistant in this sample, lending support to the hypothesis that the compact group environment inhibits moderate SSFRs. We note a curvature in the colorspace distribution, which is fully consistent with increasing dust temperature as the activity in a galaxy increases. This full sample of 49 compact groups allows us to subdivide the data according to physical properties of the groups. An analysis of these subsamples indicates that neither projected physical diameter nor density show a trend in colorspace within the values represented by this sample. We hypothesize that the apparent lack of a trend is due to the relatively small range of properties in this sample. Thus, the relative influence of stochastic effects becomes dominant. We analyze spectral energy distributions of member galaxies as a function of their location in colorspace and find that galaxies in different regions of MIR colorspace contain dust with varying temperatures and/or PAH emission.Comment: 24 pages, 13 figures. Accepted for publication in The Astronomical Journa

BoostNet: Bootstrapping detection of socialbots, and a case study from Guatemala

We present a method to reconstruct networks of socialbots given minimal input. Then we use Kernel Density Estimates of Botometer scores from 47,000 social networking accounts to find clusters of automated accounts, discovering over 5,000 socialbots. This statistical and data driven approach allows for inference of thresholds for socialbot detection, as illustrated in a case study we present from Guatemala.Comment: 7 pages, 4 figure

The graduate entry generation: a qualitative study exploring the factors influencing the career expectations and aspirations of a graduating cohort of graduate entry dental students in one London institution

Background: Dentistry in the UK has a number of new graduate-entry programmes. The aim of the study was to explore the motivation, career expectations and experiences of final year students who chose to pursue a dental career through the graduate entry programme route in one institution; and to explore if, and how, their intended career expectations and aspirations were informed by this choice. Method: In-depth interviews of 14 graduate entry students in their final year of study. Data were transcribed verbatim and analysed using framework analysis. Results: There were three categories of factors influencing students' choice to study dentistry through graduate entry: 'push', 'pull' and 'mediating'. Mediating factors related to students' personal concerns and circumstances, whereas push and pull factors related to features of their previous and future careers and wider social factors. Routes to Graduate Entry study comprised: 'early career changers', 'established career changers' and those pursuing 'routes to specialisation'. These routes also influenced the students' practice of dentistry, as students integrated skills in their dental studies, and encountered new challenges. Factors which students believed would influence their future careers included: vocational training; opportunities for specialisation or developing special interests and policy-related issues, together with wider professional and social concerns. The graduate entry programme was considered 'hard work' but a quick route to a professional career which had much to offer. Students' felt more could have been made of their pre-dental studies and/or experience during the programme. Factors perceived as influencing students' future contribution to dentistry included personal and social influences. Overall there was strong support for the values of the NHS and 'giving back' to the system in their future career. Conclusion: Graduate entry students appear to be motivated to enter dentistry by a range of factors which suit their preferences and circumstances. They generally embrace the programme enthusiastically and seek to serve within healthcare, largely in the public sector. These students, who carry wider responsibilities, bring knowledge, skills and experience to dentistry which could be harnessed further during the programme. The findings suggest that graduate entry students, facilitated by varied career options, will contribute to an engaged workforce

Dopamine-D1 and δ-opioid receptors co-exist in rat striatal neurons

Cocaine’s enhancement of dopaminergic neurotransmission in the mesolimbic pathway plays a critical role in the initial reinforcing properties of this drug. However, other neurotransmitter systems are also integral to the addiction process. A large body of data indicates that opioids and dopamine together mediate emotional and reinforced behaviors. In support of this, cocaine-mediated increases in activation of dopamine D1 receptors (D1R) results in a desensitization of δ-opioid receptor (DOR) signaling through adenylyl cyclase (AC) in striatal neurons. To further define cellular mechanisms underlying this effect, the subcellular distribution of DOR and D1R was examined in the rat dorsolateral striatum. Dual immunoperoxidase/gold-silver detection combined with electron microscopy was used to identify DOR and D1R immunoreactivities in the same section of tissue. Semi-quantitative analysis revealed that a subset of dendritic cellular profiles exhibited both DOR and D1R immunoreactivities. Of 165 randomly sampled D1R immunoreactive profiles, 43% contained DOR. Similarly of 198 DOR-labeled cellular profiles, 52% contained D1R. The present data provide ultrastructural evidence for co-existence between DOR and D1R in striatal neurons, suggesting a possible mechanism whereby D1R modulation may alter DOR function

Spatiotemporal dynamics of quantum jumps with Rydberg atoms

We study the nonequilibrium dynamics of quantum jumps in a one-dimensional chain of atoms. Each atom is driven on a strong transition to a short-lived state and on a weak transition to a metastable state. We choose the metastable state to be a Rydberg state so that when an atom jumps to the Rydberg state, it inhibits or enhances jumps in the neighboring atoms. This leads to rich spatiotemporal dynamics that are visible in the fluorescence of the strong transition.Comment: 10 page

Impingement of Water Droplets on NACA 65A004 Airfoil at 8 deg Angle of Attack

The trajectories of droplets in the air flowing past an NACA 65AO04 airfoil at an angle of attack of 8 deg were determined.. The amount of water in droplet form impinging on the airfoil, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface were calculated from the trajectories and presented to cover a large range of flight and atmospheric conditions. These impingement characteristics are compared briefly with those previously reported for the same airfoil at an angle of attack of 4 deg

Conditions for electron-cyclotron maser emission in the solar corona

Context. The Sun is an active source of radio emission ranging from long duration radio bursts associated with solar flares and coronal mass ejections to more complex, short duration radio bursts such as solar S bursts, radio spikes and fibre bursts. While plasma emission is thought to be the dominant emission mechanism for most radio bursts, the electron-cyclotron maser (ECM) mechanism may be responsible for more complex, short-duration bursts as well as fine structures associated with long-duration bursts. Aims. We investigate the conditions for ECM in the solar corona by considering the ratio of the electron plasma frequency {\omega}p to the electron-cyclotron frequency {\Omega}e. The ECM is theoretically possible when {\omega}p/{\Omega}e < 1. Methods. Two-dimensional electron density, magnetic field, plasma frequency, and electron cyclotron frequency maps of the off- limb corona were created using observations from SDO/AIA and SOHO/LASCO, together with potential field extrapolations of the magnetic field. These maps were then used to calculate {\omega}p/{\Omega}e and Alfven velocity maps of the off-limb corona. Results. We found that the condition for ECM emission ({\omega}p/{\Omega}e < 1) is possible at heights < 1.07 R_sun in an active region near the limb; that is, where magnetic field strengths are > 40 G and electron densities are greater than 3x10^8 cm-3. In addition, we found comparatively high Alfv\'en velocities (> 0.02 c or > 6000 km s-1) at heights < 1.07 R_sun within the active region. Conclusions. This demonstrates that the condition for ECM emission is satisfied within areas of the corona containing large magnetic fields, such as the core of a large active region. Therefore, ECM could be a possible emission mechanism for high-frequency radio and microwave bursts.Comment: 4 pages, 3 figure