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Geopotential and orthometric height differences between distant points can be measured via timescale comparisons between atomic clocks. Modern optical atomic clocks have residual instabilities on the order of 10^-18}, allowing height differences of around 1 cm to be measured. Frequency transfer via free-space optical links will be needed for measurements where linking the clocks via optical fiber is not possible, but requires line of sight between the clock locations, which is not always practical due to local terrain or over long distances. We present an active optical terminal, phase stabilization system, and phase compensation processing method robust enough to enable optical frequency transfer via a flying drone, greatly increasing the flexibility of free-space optical clock comparisons. We demonstrate a residual instability of 2.5x10^-18 after 3 s of integration, corresponding to a height difference of 2.3 cm, suitable for applications in geodesy, geology, and fundamental physics experiments.

We report on the development of a system called velocimetry by actively stabilised coherent optical transfer (VASCOT) that is capable of overcoming these challenges. VASCOT optically tracks the phase of the returned signal to allow for narrow-band photo-detection, thus transferring the requirements on the photodetector bandwidth to the phase-tracking bandwidth. The pointing challenges are handled by an active tracking terminal capable of suppressing angular pointing errors to the moving target. VASCOT is experimentally demonstrated over a 584 m atmospheric link to a corner-cube retro-reflector (CCR) on an airborne drone, with cycleslip-free phase tracking achieved for the three minute experiment. It was shown that the in-line target velocity measurement could achieve residual uncertainties below 2 nm/s within 5 s of averaging. VASCOT was also able to provide an absolute range measurement with a statistical error of ±13.7 mm, that agreed with an independent GPS-derived range measurement to within the uncertainty of the GPS module.

Free-space optical communications are poised to alleviate the data-flow bottleneck experienced by spacecraft as traditional radio frequencies reach their practical limit. While enabling orders-of-magnitude gains in data rates, optical signals impose much stricter pointing requirements and are strongly affected by atmospheric turbulence. Coherent detection methods, which capitalize fully on the available degrees of freedom to maximize data capacity, have the added complication of needing to couple the received signal into single-mode fiber. In this paper we present results from a coherent 1550 nm link across turbulent atmosphere between a deployable optical terminal and a drone-mounted retroreflector. Through 10 Hz machine vision optical tracking with nested 200 Hz tip/tilt adaptive optics stabilisation, we corrected for pointing errors and atmospheric turbulence to maintain robust single mode fiber coupling, resulting in an uninterrupted 100 Gbps optical data link while tracking at angular rates of up to 1.5 deg/s, equivalent to that of spacecraft in low earth orbit. With the greater data capacity of coherent communications and compatibility with extant fiber-based technologies being demonstrated across static links, ground-to-low earth orbit links of Terabits per second can ultimately be achieved with capable ground stations.

Corner cube retroreflectors are commonly used as cooperative targets in free-space laser applications. The previous literature suggests that due to path reciprocity, a retroreflected beam is self-corrected across a turbulent atmosphere and should show no angle-of-arrival variability in the near field. This is at odds with recent experiments that rely on angle-of-arrival measurements in retroreflected beams for effective tip/tilt correction. In this Letter we investigate the mechanism behind observed angle-of-arrival variability using numerical field propagation to model various transceiver and retroreflector geometries. We determine that asymmetric truncation of a curved wavefront at the retroreflector, transceiver, or both, results in a difference in tip/tilt between the transmitted and reflected wavefronts. This difference propagates as angle-of-arrival variation at the transceiver despite reciprocity, providing the error signal necessary for adaptive optics tip/tilt correction without a remote beacon.

Adaptive optics pre-compensation of free-space optical communications uplink from ground to space is complicated by the “point ahead angle” due to spacecraft velocity and the finite speed of light, as well as anisoplanatism of the uplink beam and the wavefront beacon. This Letter explores how pre-compensation varies with the number of spatial modes applied and how it varies with a beacon at the point-ahead angle versus a downlink beacon. Using a w0 = 16 cm Gaussian beam propagating through a modified Hufnagel–Valley model as an example, we find pre-compensation performance plateaus beyond ∼100 applied modes regardless of integrated turbulence strength, and that a point ahead beacon provides a 1–4 dB gain in median received power and an order-of-magnitude reduction in scintillation over a downlink beacon at wavelengths typical of optical communications. Modeling tailored to specific scenarios should be conducted to determine whether implementing a resource-intensive point ahead beacon is the optimum path to meeting link requirements.

The Facility AO systems at the LBT are based around the two Adaptive Secondary Mirrors (ASM) and the Pyramid Wavefront Sensors (PWFS), the latter being recently upgraded as part of the SOUL project in order to provide improved image quality performance and greater faint target sensitivity, at the LUCI and LBTI ports. These represent operational AO Systems with unique challenges for maintaining their optimal operational status. Based on our experience, especially over the last seven years, we present our approach to provide the readiness of the AO systems at all times including routine calibration, monitoring, and maintenance activities necessary to keep their performance at an optimal level. We also address intervention activities to improve the ASMs’ reliability and robustness.

Improved Adaptive Optics (AO) systems continue to revolutionize ground-based astronomy. Key to understanding a new AO systems capability is a quantitative measurement of performance, such as the Strehl Ratio (SR). At the Large Binocular Telescope (LBT) we have undertaken a program to monitor the performance of our AO system in regular use for science operations. Input to our analysis includes data taken specifically for this purpose during twilight and on engineering nights. We report our findings thus far and in particular discuss the challenges of collecting consistent data sets in twilight, the methods we used to overcome those challenges, and preliminary results from data collected so far.

Demonstration of the stability of traits newly introduced into a plant genome via genetic engineering approaches comprise a significant portion of the safety assessment that these products undergo prior to receiving the requisite regulatory approvals enabling commercial authorization. Different regions of the world have different regulatory requirements and many ask similar questions from multiple and overlapping perspectives. The entire central dogma, that is stability at the DNA level, mRNA level and protein level, is assessed for each product, although only a few regulatory authorities request data at the mRNA level. In this article, we present inheritance data obtained during the safety assessment of biotech products representing specific transgenic events in several crop species including Brassica napus (canola); canola quality Brassica juncea (yellow seeded canola); Glycine max (soybean), and Gossypium hirsutum (cotton) in which different traits have been introduced. The data presented confirm that all events examined were nuclear insertions that resulted in typical Mendelian Inheritance patterns and that the proteins are expressed similarly across multiple generations regardless of whether they were from backcrossed or outcrossed generations. These results demonstrate that newly inserted genes are transmitted to their progeny in a stable manner similar to that of endogenous genes. Further, the findings demonstrate that assessments of multigenerational stability have very limited value to a safety assessment.

We present an overview of the AO systems at the LBT concentrating on the unique capability of two adaptive secondary mirrors and pyramid wavefront sensing. These permit AO compensation down to 16th magnitude guide stars enhancing field coverage as well as extreme AO compensation for bright targets.

We study numerically the region of convergence of the normal form transformation for the case of the Charney–Hasagawa–Mima (CHM) equation to investigate whether certain finite amplitude effects can be described in normal form coordinates. Specifically, we consider a Galerkin truncation of the CHM equation to four Fourier modes, and ask: Can the finite amplitude phenomenon known as precession resonance (Bustamante et al., Phys. Rev. Lett., vol. 113, 2014, 084502) be described by the normal form variables of wave turbulence theory? The answer is no, due to the failure of convergence of the normal form transformation at the wave amplitudes required for precession resonance. We show this by first characterising precession resonance in the original system, then, searching for this resonance in the normal form equations of motion. We find a large discrepancy between the dynamics of the original system and the transformed normal form system. This prompts an investigation into the convergence of the transformation in the state space of wave amplitudes. We find that the numerically calculated region of convergence is a region of finite wave amplitudes, well beyond the usual limit of weak nonlinearity. However, the amplitudes at the boundary of this region of convergence (i.e. the amplitudes at which the normal form transformation begins to diverge) match closely with the amplitudes at which precession resonance occurs in the original system. We conclude that the precession resonance mechanism cannot be explained by the usual methods of normal forms in wave turbulence theory, so a more general theory for intermediate nonlinearity is required.

We report near simultaneous imaging using LMIRCam on the LBTI of the quadruply imaged lensed quasar HS 0810+2554 at wavelengths of 2.16, 3.7 and $4.78~\mu$m with a Full Width Half Max (FWHM) spatial resolution of $0^{\prime\prime}\!\!.13$, $0^{\prime\prime}\!\!.12$ and $0^{\prime\prime}\!\!.15$ respectively, comparable to HST optical imaging. In the $\rm{z} = 1.5$ rest frame of the quasar, the observed wavelengths correspond to 0.86, 1.48, and $1.91~\mu$m respectively. The two brightest images in the quad, A and B, are clearly resolved from each other with a separation of $0.187^{\prime\prime}$. The flux ratio of these two images (A/B) trends from 1.79 to 1.23 from 2.16 to $4.78~\mu$m. The trend in flux ratio is consistent with the $2.16~\mu$m flux originating from a small sized accretion disk in the quasar that experiences only microlensing. The excess flux above the contribution from the accretion disk at the two longer wavelengths originates from a larger sized region that experiences no microlensing. A simple model employing multiplicative factors for image B due to stellar microlensing $(m)$ and sub-structure millilensing $(M)$ is presented. The result is tightly constrained to the product $m\times M=1.79$. Given the observational errors, the 60\% probability contour for this product stretches from $m= 2.6$, $M = 0.69$ to $m= 1.79$, $M = 1.0$, where the later is consistent with microlensing only., Comment: accepted AJ

Uniquely designed with two 8.4m mirrors, a 22.8m interferometric baseline, and the collecting area of an 11.8m telescope, the Large Binocular Telescope Observatory (LBTO), has a narrow window of opportunity to exploit its status as the “first” of the ELTs. Prompted by urgency to maximum scientific output during this favorable interval, we undertook a multi-year project to reshape the user experience. The initial stage, implementing a new suite of software to facilitate proposal submission, script creation, binocular planning, and nighttime execution, is nearing completion. Reuse and adaptation of existing software, particularly Gemini Observatory’s cross-platform PIT and OT, proved critical, although as expected, we encountered many challenges presented by our one-of-a-kind binocular design and operations. We hope to leverage our success in the early phases of this project toward further improvement of our science operations model, specifically, augmenting our nighttime operations to include observatory-led observing. We plan to focus this observing mode primarily on instruments that require block scheduling and/or superb and rare conditions such as our newly commissioned GLAO system, ARGOS. In this paper, we outline our workflow, describe lessons learned, and present our resulting software products. We also detail future development toward our ultimate goal, improved efficiency and user interactions throughout every step of the observing experience.

We report results on the explicit parameterisation of discrete Rossby-wave resonant triads of the Charney-Hasegawa-Mima equation in the small-scale limit (i.e. large Rossby deformation radius), following up from our previous solution in terms of elliptic curves [6]. We find an explicit parameterisation of the discrete resonant wavevectors in terms of two rational variables. We show that these new variables are restricted to a bounded region and find this region explicitly. We argue that this can be used to reduce the complexity of a direct numerical search for discrete triad resonances. Also, we introduce a new direct numerical method to search for discrete resonances. This numerical method has complexity O ( N 3 ) (up to logarithmic factors), where N is the largest wavenumber in the search. We apply this new method to find all discrete irreducible resonant triads in the wavevector box of size 5000, in a calculation that took about 10.5 days on a 16-core machine. Finally, based on our method of mapping to elliptic curves, we discuss some dynamical implications regarding the spread of quadratic invariants across scales via resonant triad interactions, through the analysis of sharp bounds on the relative sizes of the resonantly interacting wavevectors.

Objective To assess the influence of tumour zonality on biochemical recurrence (BCR) after radical prostatectomy (RP) with a histologically confirmed positive surgical margin (PSM). Patients and Methods Data from 382 patients that underwent RP with either transition zone (TZ) or peripheral zone (PZ) tumours involving PSMs between 1998 and 2010 were retrieved from the Abbott West Australian Prostatectomy Database. Statistical analysis was used to evaluate the relationship of various tumour clinicopathological parameters, e.g. zonal origin of tumour, tumour volume, Gleason score, and stage to the development of BCR Results There were 51 TZ and 331 PZ tumours with PSMs identified. The TZ tumours compared with PZ tumours were larger (median 5.67 vs 3.64 mL, P < 0.001), more frequently lower grade (Gleason score 6 33% vs 5%, P < 0.01), organ confined (51% vs 35.6%, P = 0.073), and preferentially involved the bladder neck (49% vs 6%, P < 0.001). Tumour zonality was not associated with BCR for the entire cohort. TZ and PZ tumours had similar 5-year BCR-free survival rates (58% vs 63%, P = 0.691) and comparable time to development of BCR (14.4 vs 19.2 months, P = 0.346). On univariate analysis, preoperative PSA level, PSM at the bladder neck, tumour volume, Gleason score (P < 0.001) and tumour stage were independent predictors of BCR for the entire cohort. On multivariate analysis tumour volume and Gleason score retained significance as independent predictors of BCR. Tumour zonality was not directly associated with BCR. Of the patients who received adjuvant therapy, the incidence of BCR was similar for TZ and PZ tumours (58% vs 67%, P = 0.077), although TZ tumours failed significantly earlier (mean 4.4 vs 16.4 months, P = 0.037). Conclusions PSA recurrence in patients with histologically confirmed PSMs after RP is independent of the zonal location of the index tumour. However, tumour zonal origin may have an indirect influence on PSA relapse, as TZ tumours tend to be of large volume and more likely involve the bladder neck margin, both risk factors for BCR. Bladder neck margin involvement is associated with higher rates of BCR than other sites of PSMs. The preoperative identification of TZ tumours might aid surgical planning with appropriate alteration of RP technique to incorporate wider surgical margins at the bladder neck. Adjuvant radiotherapy appears to be associated with adverse outcome for TZ tumours, a novel finding which warrants further investigation.

In this paper we detail the process the LBTO followed to chose software for reuse and modification to support binocular queue operations. We outline the survey of initial candidate solutions, how and why the final selection was made, and describe our requirements gap analysis for LBTO binocular use. We provide details of our software development approach including a project road map and phased release strategy. We provide details of added LBTO functionality, discuss issues, and suggest some reuse lessons learned. We conclude with discussion of known desired enhancements to be addressed in future release cycles.

The Large Binocular Telescope Observatory (LBTO), a joint scientific venture between the Instituto Nazionale di Astrofisica (INAF), LBT Beteiligungsgesellschaft (LBTB), University of Arizona, Ohio State University (OSU), and the Research Corporation, is one of the newest additions to the world’s collection of large optical/infrared ground-based telescopes. With its unique, twin 8.4m mirror design providing a 22.8 meter interferometric baseline and the collecting area of an 11.8m telescope, LBT has a window of opportunity to exploit its singular status as the “first” of the next generation of Extremely Large Telescopes (ELTs). Prompted by urgency to maximize scientific output during this favorable interval, LBTO recently re-evaluated its operations model and developed a new strategy that augments classical observing with queue. Aided by trained observatory staff, queue mode will allow for flexible, multi-instrument observing responsive to site conditions. Our plan is to implement a staged rollout that will provide many of the benefits of queue observing sooner rather than later -- with more bells and whistles coming in future stages. In this paper, we outline LBTO's new scientific model, focusing specifically on our “lean” resourcing and development, reuse and adaptation of existing software, challenges presented from our one-of-a-kind binocular operations, and lessons learned. We also outline further stages of development and our ultimate goals for queue.

Prostatic adenocarcinomas arising within the transition zone (Tz) are distinct from peripheral zone (Pz) tumors as regards biological aggression and mechanism of extraprostatic extension. Reliable biopsy identification of Tz tumors would allow targeted surgical approaches more likely to preserve erectile function without compromising surgical margins. Previous studies have demonstrated the presence of eosinophilic cytoplasmic granules (prostate secretory granules, or PSGs) after glutaraldehye fixation, with apparent depletion in neoplasia. We investigated PSG content, columnar cells, pale cytoplasm, and luminal secretions of both Pz and Tz tumors in 44 radical prostatectomies (RPs) and 135 biopsies fixed with gluteraldehyde-based fixative. Retention of PSG is characteristic of Tz carcinoma and infrequently seen in Pz tumors, and a combination of PSG greater than 30% with either columnar cells, pale cells, or secretions in biopsies is a reliable marker for Tz origin. When these criteria were prospectively applied to 3929 cases with follow-up RP, 510 Tz tumors were correctly identified on biopsy (sensitivity, 21.4%; specificity, 97.4%). Biopsy-identified Tz tumors had higher volumes (mean, 3.48 versus 1.81 cm(3); P.001) and higher rates of margin positivity (22.5% versus 17.5%; P = .008) than did Tz tumors not identified preoperatively. Mean Tz tumor length in biopsies was 2.0 mm, with no correlation between tumor volume at RP and tumor length on biopsy. Tz tumors are reliably identified on biopsy, based on a combination of PSG retention with either columnar cells, pale cells, or secretion. Biopsy-identified Tz tumors may not be suitable for active surveillance because of an associated high probability of large tumor volume and increased risk of positive margins at RP.

We present deep CMDs for two Subaru Suprime-Cam fields in the Virgo Stellar Stream(VSS)/Virgo Overdensity(VOD) and compare them to a field centred on the highest concentration of Sagittarius (Sgr) Tidal Stream stars in the leading arm, Branch A of the bifurcation. A prominent population of MS stars is detected in all three fields and can be traced as faint as g~24 mag. Using theoretical isochrone fitting we derive an age of 9.1(+1.0;-1.1)Gyr, a median abundance of [Fe/H]=-0.70 (+0.15; -0.20)dex and d_helio of 30.9+-3.0kpc for the MS of the Sgr Stream Branch A. The dominant main sequence populations in the two VSS/VOD fields (Lsun ~265 deg, Bsun ~13 deg) are located at a mean distance of 23.3+-1.6kpc and have an age ~8.2Gyr and an abundance [Fe/H]=-0.67(+0.16;-0.12)dex similar to the Sgr Stream stars. These parameters are also in good agreement with the age of the main population in the Sagittarius dwarf (8.0+-1.5Gyr). They also agree with the peak in the metallicity distribution of 2-3Gyr old M-giants, [Fe/H] ~ -0.6dex, in the Sgr leading arm north. We then compare the results from the VSS/VOD fields with the Sgr Tidal Stream model by Law & Majewski based on a triaxial Galactic halo that is calibrated with SDSS Sgr A-branch and 2MASS M-giant stars. We find that the most prominent feature in the CMDs, the MS population at 23kpc, is not explained by the model. Instead the model predicts in these directions a low density filamentary structure of Sgr debris stars at ~9kpc and a slightly higher concentration of Sgr stars spread from 42-53kpc. At best there is only marginal evidence for the presence of these populations in our data. Our findings then suggest that while there are probably some Sgr debris stars present, the dominant stellar population in the VOD originates from a different halo structure that has almost identical age and metallicity as some sections of the Sgr tidal stream., 11 pages, 8 figures, 5 tables, accepted for publication in ApJ

We investigate the kinematic and photometric properties of the Segue 3 Milky Way companion using Keck/DEIMOS spectroscopy and Magellan/IMACS g and r-band imaging. Using maximum likelihood methods to analyze the photometry, we study the structure and stellar population of Segue 3. We find the half-light radius of Segue 3 is 26" +/- 5" (2.1 +/- 0.4 pc, for a distance of 17 kpc) and the absolute magnitude is a mere M_V = 0.0 +/- 0.8 mag, making Segue 3 the least luminous old stellar system known. We find Segue 3 to be consistent with a single stellar population, with an age of 12.0 +1.5/-0.4 Gyr and an [Fe/H] of -1.7 +0.07/-0.27. Line-of-sight velocities from the spectra are combined with the photometry to determine a sample of 32 stars which are likely associated with Segue 3. The member stars within three half-light radii have a velocity dispersion of 1.2 +/- 2.6 km/s. Photometry of the members indicates the stellar population has a spread in [Fe/H] of, 16 pages, 8 figures, 3 tables. Accepted to AJ on July 15, 2011

[Abridged] A specialized data mining algorithm has been developed using wide-field photometry catalogues, enabling systematic and efficient searches for resolved, extremely low surface brightness satellite galaxies in the halo of the Milky Way (MW). Tested and calibrated with the Sloan Digital Sky Survey Data Release 6 (SDSS-DR6) we recover all fifteen MW satellites recently detected in SDSS, six known MW/Local Group dSphs in the SDSS footprint, and 19 previously known globular and open clusters. In addition, 30 point source overdensities have been found that correspond to no cataloged objects. The detection efficiencies of the algorithm have been carefully quantified by simulating more than three million model satellites embedded in star fields typical of those observed in SDSS, covering a wide range of parameters including galaxy distance, scale-length, luminosity, and Galactic latitude., 22 pages, submitted to AJ. You can find a version with full resolution figures at http://msowww.anu.edu.au/~jerjen/SMS_papers.html. Replacement version includes small clarification of discussion and astro-ph numbers in references

During the course of a systematic search for low surface brightness Milky Way satellite galaxies we have discovered a previously unidentified stellar overdensity in the Sloan Digital Sky Survey. This overdensity has all the hallmarks of an extremely faint Dwarf Spheroidal companion which we designate boo. The object is consistent with an old (∼12 Gyr) metal-poor ([Fe/H] ≃-2.0) population at a distance modulus (m-M)=18.9±0.5 mag. We estimate a total magnitude for boo of MV∼ -3.1±1.1 mag and a half-light radius of rh∼72±28 pc.

As part of preparations for a southern sky search for faint Milky Way dwarf galaxy satellites, we report the discovery of a stellar overdensity in the Sloan Digital Sky Survey Data Release 5, lying at an angular distance of only 1.5 degrees from the recently discovered Bo{\"o}tes dwarf. The overdensity was detected well above statistical noise by employing a sophisticated data mining algorithm and does not correspond to any catalogued object. Overlaid isochrones using stellar population synthesis models show that the color-magnitude diagram of that region has the signature of an old (12 Gyr), metal-poor (${\rm Fe/H}\approx-2.0$) stellar population at a tentative distance of 60 kpc, evidently the same heliocentric distance as the Bo\"otes dwarf. We estimate the new object to have a total magnitude of $M_{V}\sim-3.1\pm1.1$ mag and a half-light radius of $r_{h}=4'.1\pm1'.6$ ($72\pm28$ pc) placing it in an apparent $40, Comment: Accept by ApJL May 9, 2007

[abridged] We present MMT/Megacam imaging in Sloan $g$ and $r$ of the extremely low luminosity Bo\"otes II Milky Way companion. We use a bootstrap approach to perform robust measurements of, and uncertainties on, Bo\"otes II's distance, luminosity, size, and morphology. We show that Bo\"otes II's stellar population is old and metal-poor ([Fe/H] $\lta$ -2). Assuming a stellar population like that of M92, Bo\"otes II is at a distance of 42 $\pm$ 2 kpc, closer than the initial published estimate of 60 $\pm$ 10 kpc. This distance revision, combined with a more robust measurement of Bo\"otes II's structure with a Plummer model (exponential model) results in a more compact half-light size of $r_h\simeq 36 (33) \pm 9 (10)$ pc and lower luminosity of $M_V\simeq-2.4 (-2.2) \pm 0.7 (0.7)$ mag. This revised size and luminosity move Bo\"otes II into a region of size-luminosity space not previously known to be occupied by old stellar populations, but also occupied by the recently discovered Milky Way satellites Willman 1 and SEGUE 1. We show that the apparently distorted morphology of Bo\"otes II is not statistically significant given the present data. We use a tidal argument to support a scenario where Bo\"otes II is a dwarf galaxy (dark matter dominated) rather than a globular cluster (not dark matter dominated). However, we can not rule out that Bo\"otes II is a star cluster on the verge of disruption, such as Palomar 5., Comment: 10 pages, 8 figures. ApJ accepted. Conclusions are unchanged, but content and figures have changed substantively in this accepted version