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"Gardner, R. W."
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Caching Servers for ATLAS
As many LHC Tier-3 and some Tier-2 centers look toward streamlining operations, they are considering autonomously managed storage elements as part of the solution. These storage elements are essentially file caching servers. They can operate as whole file or data block level caches. Several implementations exist. In this paper we explore using XRootD caching servers that can operate in either mode. They can also operate autonomously (i.e. demand driven), be centrally managed (i.e. a Rucio managed cache), or operate in both modes. We explore the pros and cons of various configurations as well as practical requirements for caching to be effective. While we focus on XRootD caches, the analysis should apply to other kinds of caches as well.
Journal Article
Big Data Tools as Applied to ATLAS Event Data
Big Data technologies have proven to be very useful for storage, processing and visualization of derived metrics associated with ATLAS distributed computing (ADC) services. Logfiles, database records, and metadata from a diversity of systems have been aggregated and indexed to create an analytics platform for ATLAS ADC operations analysis. Dashboards, wide area data access cost metrics, user analysis patterns, and resource utilization efficiency charts are produced flexibly through queries against a powerful analytics cluster. Here we explore whether these techniques and associated analytics ecosystem can be applied to add new modes of open, quick, and pervasive access to ATLAS event data. Such modes would simplify access and broaden the reach of ATLAS public data to new communities of users. An ability to efficiently store, filter, search and deliver ATLAS data at the event and/or sub-event level in a widely supported format would enable or significantly simplify usage of machine learning environments and tools like Spark, Jupyter, R, SciPy, Caffe, TensorFlow, etc. Machine learning challenges such as the Higgs Boson Machine Learning Challenge, the Tracking challenge, Event viewers (VP1, ATLANTIS, ATLASrift), and still to be developed educational and outreach tools would be able to access the data through a simple REST API. In this preliminary investigation we focus on derived xAOD data sets. These are much smaller than the primary xAODs having containers, variables, and events of interest to a particular analysis. Being encouraged with the performance of Elasticsearch for the ADC analytics platform, we developed an algorithm for indexing derived xAOD event data. We have made an appropriate document mapping and have imported a full set of standard model W/Z datasets. We compare the disk space efficiency of this approach to that of standard ROOT files, the performance in simple cut flow type of data analysis, and will present preliminary results on its scaling characteristics with different numbers of clients, query complexity, and size of the data retrieved.
Journal Article
Attitudes of NICU professionals regarding feeding blood-tinged colostrum or milk
Objective:
Mothers of neonatal intensive care unit (NICU) patients sometimes bring expressed milk that is blood tinged to the NICU. In certain instances, the blood contamination appears minimal, whereas in others, the milk is quite dark pink. We have observed inconsistencies in practice regarding whether or not to feed blood-tinged colostrum or milk to NICU patients. We know of no evidence that establishes best practice in this area, and thus we sought to determine attitudes of NICU professionals on which to base a potentially best practice.
Study Design:
We conducted a web-based anonymous survey of attitudes of NICU professionals at Intermountain Healthcare regarding feeding blood-tinged expressed milk to NICU patients. These professionals included neonatologists, neonatal nurse practitioners, NICU nurses, NICU dieticians and lactation consultants.
Result:
Survey results were returned from 64% (426 of 667) of those to whom it was sent. A total of 75% of respondents reported that their practice was NOT to feed the blood-tinged milk illustrated in the figure as sample 2, and nearly all respondents (98%) reported that they would NOT feed the milk illustrated as sample 3. The majority of the neonatologists (56%) and the lactation consultants (58%) recommended feeding moderately bloody milk (sample 2), whereas only 22% of the neonatal nurse practitioners (NNPs), NICU nurses and NICU dieticians recommended feeding such samples (<0.001). The most frequently selected reason for NOT feeding blood-tinged milk was that it would likely cause gastrointestinal upset and feeding intolerance (selected by 77%). The majority (87%) overestimated the amount of blood contaminating a milk sample (sample 3).
Conclusion:
As colostrum and human milk feedings can be of value to NICU patients, evidence should be assembled to document whether feeding blood-tinged samples indeed have the problems listed by the survey respondents. Such evidence is needed to enable informed decisions involving the benefits vs risks of feeding blood-tinged expressed milk to NICU patients.
Journal Article
On-Sky Performance of the SPT-3G Frequency-Domain Multiplexed Readout
Frequency-domain multiplexing (fMux) is an established technique for the readout of large arrays of transition-edge sensor (TES) bolometers. Each TES in a multiplexing module has a unique AC voltage bias that is selected by a resonant filter. This scheme enables the operation and readout of multiple bolometers on a single pair of wires, reducing thermal loading onto sub-Kelvin stages. The current receiver on the South Pole Telescope, SPT-3G, uses a 68x fMux system to operate its large-format camera of
∼
16,000 TES bolometers. We present here the successful implementation and performance of the SPT-3G readout as measured on-sky. Characterization of the noise reveals a median pair-differenced 1/f knee frequency of 33 mHz, indicating that low-frequency noise in the readout will not limit SPT-3G’s measurements of sky power on large angular scales. Measurements also show that the median readout white noise level in each of the SPT-3G observing bands is below the expectation for photon noise, demonstrating that SPT-3G is operating in the photon-noise-dominated regime.
Journal Article
A Measurement of Gravitational Lensing of the Cosmic Microwave Background Using SPT-3G 2018 Data
We present a measurement of gravitational lensing over 1500 deg\\(^2\\) of the Southern sky using SPT-3G temperature data at 95 and 150 GHz taken in 2018. The lensing amplitude relative to a fiducial Planck 2018 \\(\\Lambda\\)CDM cosmology is found to be \\(1.020\\pm0.060\\), excluding instrumental and astrophysical systematic uncertainties. We conduct extensive systematic and null tests to check the robustness of the lensing measurements, and report a minimum-variance combined lensing power spectrum over angular multipoles of \\(50
Paper
A measurement of the mean central optical depth of galaxy clusters via the pairwise kinematic Sunyaev-Zel'dovich effect with SPT-3G and DES
We infer the mean optical depth of a sample of optically-selected galaxy clusters from the Dark Energy Survey (DES) via the pairwise kinematic Sunyaev-Zel'dovich (kSZ) effect. The pairwise kSZ signal between pairs of clusters drawn from the DES Year-3 cluster catalog is detected at \\(4.1 \\sigma\\) in cosmic microwave background (CMB) temperature maps from two years of observations with the SPT-3G camera on the South Pole Telescope. After cuts, there are 24,580 clusters in the \\(\\sim 1,400\\) deg\\(^2\\) of the southern sky observed by both experiments. We infer the mean optical depth of the cluster sample with two techniques. The optical depth inferred from the pairwise kSZ signal is \\(\\bar{\\tau}_e = (2.97 \\pm 0.73) \\times 10^{-3}\\), while that inferred from the thermal SZ signal is \\(\\bar{\\tau}_e = (2.51 \\pm 0.55^{\\text{stat}} \\pm 0.15^{\\rm syst}) \\times 10^{-3}\\). The two measures agree at \\(0.6 \\sigma\\). We perform a suite of systematic checks to test the robustness of the analysis.
Paper
Performance of Al–Mn Transition-Edge Sensor Bolometers in SPT-3G
SPT-3G is a polarization-sensitive receiver, installed on the South Pole Telescope, that measures the anisotropy of the cosmic microwave background (CMB) from degree to arcminute scales. The receiver consists of ten 150-mm-diameter detector wafers, containing a total of
∼
16
,
000
transition-edge sensor (TES) bolometers observing at 95, 150, and 220 GHz. During the 2018–2019 austral summer, one of these detector wafers was replaced by a new wafer fabricated with Al–Mn TESs instead of the Ti/Au design originally deployed for SPT-3G. We present the results of in-laboratory characterization and on-sky performance of this Al–Mn wafer, including electrical and thermal properties, optical efficiency measurements, and noise-equivalent temperature. In addition, we discuss and account for several calibration-related systematic errors that affect measurements made using frequency-domain multiplexing readout electronics.
Journal Article
On-Sky Performance of the SPT-3G Frequency-Domain Multiplexed Readout
Frequency-domain multiplexing (fMux) is an established technique for the readout of large arrays of transition-edge sensor (TES) bolometers. Each TES in a multiplexing module has a unique AC voltage bias that is selected by a resonant filter. This scheme provides for the operation and readout of multiple bolometers on a single pair of wires, reducing thermal loading onto sub-Kelvin stages. The current receiver on the South Pole Telescope, SPT-3G, uses a 68x fMux system to operate its large-format camera of ~16,000 TES bolometers. We present here the successful implementation and performance of the SPT-3G readout as measured on-sky. Characterization of the noise reveals a median pair-differenced 1/f knee frequency of 33 mHz, indicating that low-frequency noise in the readout will not limit SPT-3G’s measurements of sky power on large angular scales. Measurements further show that the median readout white noise level in each of the SPT-3G observing bands is below the expectation for photon noise, demonstrating that SPT-3G is operating in the photon-noise-dominated regime.
Journal Article