Universal Time Research Articles

Sport-related Structural Brain Injury in High School and College American Football Athletes, 2002-2020: Effect of Lystedt Law.

A previous report revealed an average of 7.2 (0.67 per 100,000 participants) sport-related structural brain injuries (SRSBIs) with macroscopic lesions per year in high school (HS) and college football players. The Lystedt law and other rule changes have been implemented with intent to reduce the risk of brain injury in football. To update the profile of SRSBIs in HS and college football players and evaluate the efficacy of legislation intended to reduce brain injuries. Descriptive epidemiology study. Level 4. We retrospectively reviewed 18 academic years (July 2002 through June 2020) of SRSBIs catalogued by the National Registry of Catastrophic Sports Injuries. The incidence of SRSBIs was assessed at the HS level during the pre (July 2002 through June 2009), transitional (July 2009 through June 2014), and post (July 2014 through June 2020) universal adoption time periods of the Lystedt law. In addition, the incidence of SRSBIs during the second half of the study (2011-2012 through 2019-2020) was compared with the first half of the study (2002-2003 through 2010-2011). During the study period, there was a total of 228 SRSBIs (12.7 per year, 1.01 per 100,000 participants): 212 (93%, 11.8 per year, 1.00 per 100,000) in HS athletes and 16 (7%, 0.89 per year, 1.17 per 100,000) in college athletes. There were 52 fatalities (2.9 per year, 0.22 per 100,000 participants) with 46 (2.56 per year, 0.22 per 100,000) in HS athletes and 6 (0.33 per year, 0.43/100,000) in college athletes. There was no significant difference in risk of HS total SRSBIs or fatalities during the 3 Lystedt periods. The risk of combined SRSBI cases [relative risk (RR) = 1.22, P = 0.13] and fatalities (RR = 1.20, P = 0.52) was similar in the second half of the study compared with the first half of the study. Despite implementation of rule changes intended to reduce head injury, in particular the Lystedt law, the incidence of SRSBIs has remained unchanged. Further research is necessary to develop effective prevention programs for SRSBIs. SRSBIs remain a persistent problem in HS and college American football. The recent head injury rule changes have not been effective at reducing SRSBIs.

“What does it mean to make a picture of the now?”

“What does it mean to make a picture of the now?”

Towards a consensus on a continuous coordinated universal time

This paper explains the considerations that were important in 1972, when the current leap second procedure was adopted, to maintain a close connection between UTC, the international reference time scale, and UT1—a time scale based on the rotation of the Earth. Although some of these considerations are still relevant, the procedure for adding leap seconds creates difficulties in many modern applications that require a continuous and monotonic time scale. We present the advantages and disadvantages of the leap second procedure, and some of the problems foreseen if it is not reconsidered. We suggest the general outline of a way forward, which addresses the deficiencies in the current leap second system, and which will ensure that UTC remains an international standard that is useful and appropriate for all time and frequency applications. Further discussion and evaluation of the impact of any changes is required.

A note on the mechanics emerged from systems with a stochastic process of the time variable

Stochastic mechanics is an attempt to build a well-defined probabilistic formulation of quantum theory. This formulation proposes a deeper origin for the (non-relativistic) Schrödinger equation using a hypothesis that a massive particle with mass m is influenced by a Brownian motion having a diffusion coefficient of ħ/2m and no friction. However, the hypothetical ether (as suggested by Nelson) that causes such a Brownian motion remains uncleared. While most of the literature on stochastic mechanics follows the original interpretation given by Nelson, we present an alternative interpretation of stochastic mechanics, where the stochasticity of time, and not space, is responsible for the emergence of the quantum particle. In particular, we show that stochastic mechanics (in one dimension) can be deduced by assuming that time is a stochastic process of a universal absolute time. This replaces the proposed ether with a new notion of time for particles in the quantum regime.

Under the net: universal time, modernism, and the subversive temporality of golden age detective fiction

ABSTRACT While the relationship between modernism and its ‘sister-genre’ detective fiction [Brian McHale, Postmodern Fiction (New York: Methuen, 1987), p. 59] has tended to be characterised in oppositional terms, recent scholarship has challenged this conceptualisation, arguing that the two forms can be productively read in relation to each other. However, the ways in which detective fiction, like modernist writing, is invested in questions of temporality remains underexplored. This paper argues that detective fiction simultaneously asserts and challenges modernity’s universal, standardised time-keeping regime. This argument is developed through a detailed examination of Agatha Christie’s The Murder of Roger Ackroyd, in which the criminal’s ability to elude the net of modern time is only exceeded by the detective’s ability to reassert it, and then through a wider discussion of the way this pattern reappears throughout the genre.

The Temporal Evolution of F-Region Equatorial Ionization Anomaly Owing to the 2022 Tonga Volcanic Eruption

The dynamic evolutions of the noon ionospheric Equatorial Ionization Anomaly (EIA) owing to the 2022 Tonga volcanic eruption were investigated using the ionospheric plasma measurements from the Swarm satellite, the science experiment of the Constellation Observing Systems for Meteorology, Ionosphere, and Climate (COSMIC) mission, and the thermospheric wind observations from the Ionospheric Connection Explorer (ICON). At 14.1 universal time (UT), the noon EIA was enhanced for the upward plasma drifts, when the F2-layer was significantly uplifted from 360 km to 410 km. At 15.6 UT, because of the downward drifts, the intensity of the EIA reduced, and hmF2 decreased to 270 km. At 17–18 UT, the EIA recovered and reformed, and hmF2 increased to 350 km. A two-peak structure in the plasma was observed at Swarm altitudes. The temporal evolution might be related to the vertical plasma drifts (both downward and upward) from the E-region electric field.

Impacts of FY-4A GIIRS Water Vapor Channels Data Assimilation on the Forecast of “21·7” Extreme Rainstorm in Henan, China with CMA-MESO

A record-breaking extreme rainstorm occurred in Henan Province of China on 20 July 2021. To investigate the impacts of the Geostationary Interferometric Infrared Sounder (GIIRS) data assimilation on model analysis and forecasts of this rainfall event, the high temporal resolution GIIRS water vapor (WV) channel data were assimilated in the high-resolution CMA-MESO (Mesoscale Weather Numerical Forecast System of China Meteorological Administration) in this study. The results showed that the GIIRS WV radiance assimilation could improve the model WV analysis, which in turn adjusted the distributions of hydrometeors (radar composite reflectivities) and wind field, and finally improved the precipitation forecast. Additionally, although barely any GIIRS observations were assimilated over the cloudy area, the precipitation forecast errors of “21·7” extreme rainstorm events could be reduced by improving the structure of atmospheric circulations through the assimilation of neighboring data around Henan, especially over the upstream region. With the GIIRS WV data assimilation, the location error of maximum 24-h accumulated precipitation forecasts decreased from 128.48 km to 28.97 km (improved by 77.45%) for the cold start at 0000 UTC (Universal Time Coordinated) on 19 July 2021, and it was also reduced by about 60.52% for the warm start experiment at 0600 UTC on 19 July 2021. In addition, the GIIRS assimilation experiment showed an extraordinarily heavy rainfall area (above 250 mm/24 h) around Zhengzhou station, which did not appear in the control experiment, and was closer to the observed extreme precipitation. This study demonstrates the potential value of geostationary hyperspectral infrared sounders data assimilation in extreme weather early warning and forecasting.

Impact of Tropospheric Ties on UT1‐UTC in GNSS and VLBI Integrated Solution of Intensive Sessions

AbstractVery Long Baseline Interferometry (VLBI) intensive (INT) sessions are critical for the rapid determination and densification of Universal Time 1‐Coordinate Universal Time (UT1‐UTC), which plays an important role in satellite geodesy and space exploration missions and is not predictable over longer time scales. Due to the limited observation geometry of INT sessions with two to three stations observing about 1 hr, tropospheric gradients cannot be estimated, which degrades the UT1‐UTC precision. We investigate the impact of tropospheric ties at Global Navigation Satellite Systems (GNSSs) and VLBI co‐located stations in INT sessions from 2001 to 2021. VLBI and GNSS observations are combined on the observation level. The results are evaluated by using both UT1‐UTC and Length of Day (LOD) from consecutive sessions. We demonstrate a better agreement of 10%–30% when comparing the derived LOD to GNSS LOD for INT1, INT2, and VGOS‐2 sessions; whereas, the agreement is not improved when directly comparing UT1‐UTC to the IERS Earth Orientation Parameters (EOPs) product, potentially because INT sessions also contribute to IERS EOP products. The major impact comes from tropospheric gradient ties, whereas applying zenith delay ties does not improve or even deteriorate UT1‐UTC agreement. Gradient ties also introduce systematic biases in UT1‐UTC by around −3 to −5 μs, except for the Russian INT sessions. Regression analysis shows that the east gradient introduces systematic effects in UT1‐UTC for sessions involving Germany and USA (Hawaii), whereas for Germany–Japan and Russian sessions, the north gradient also contributes systematically.

Achieving traceability to UTC through GNSS measurements

Coordinated universal time (UTC) is the international reference for time and frequency measurement, and the basis of civil timekeeping world-wide. The reception of signals from global navigation satellite systems (GNSS) as a source of time and frequency (synchronization and syntonization) has found widespread use in virtually all user sectors, including electrical power supply, telecommunications, and financial institutions. This paper summarizes the concept of metrological traceability and the practices employed in the time and frequency metrology community for achieving it. Practical steps are proposed to ensure that traceability to UTC from GNSS signal reception is available to a wide community of users, addressing different levels of required uncertainty in time and frequency offset from UTC. We suggest some practical measures that can be followed by users, and improvements to the services provided by National Metrology Institutes (NMIs).

Development of a Semiconductor Time Relay for Locomotives

Purpose. The need to replace the outdated element base of locomotive electrical apparatuses is urgent under conditions of locomotive overhaul to extend their service life. The main aim of the work is to reduce costs for the operation and repair of rolling stock by increasing the reliability of electrical apparatuses, the introduction of unified technical solutions. Methodology. Using the system-historical approach, the advantages and disadvantages of the main design principles of electrical apparatuses of locomotives are found out. The improvement directions of the elemental base of the time relay have been determined. The need to develop unified technical solutions for the implementation of locomotive time relays is substantiated. Using the methods of applied theory of digital machines and circuit engineering, a semiconductor time relay for locomotives was developed, which provides the possibility of implementing 23 options for time delay without changing the relay design. The proposed methodology allows designing universal electronic relays with any ranges of time delays. A combination of binary counters and a multiplexer is used as the main elements of the time delay control. The absence of elements of control capacitance and active resistance (RC circuits) in the scheme of the proposed semiconductor time relay allows ensuring the stability of the time relay characteristics over the entire operating interval, reducing the maintenance and repair costs of electrical apparatuses. Findings. A unified time relay with a wide range of time delay and the possibility of connecting electrical circuits of locomotives with a supply voltage of 50 and 110 V has been developed. The obtained results make it possible to predict the further development of semiconductor time relays and to apply the developed semiconductor (electronic) time relay for all types of railway rolling stock. Originality. In the work, the development of technologies and the element base of locomotive electrical apparatuses were analysed. The need to improve the element base of electrical apparatuses is substantiated using a time relay example. Practical value. Based on the proposed technical solutions, it is possible to produce a universal semiconductor time relay for locomotives.

ROTI Keograms based on CMONOC to characterize the ionospheric irregularities in 2014

Ionospheric irregularities have been studied since ~ 70 years ago. With the development of Global Navigation Satellite system (GNSS), networks of GNSS receivers have been used to obtain the characteristics of the irregularities, including the drift velocity, the structure, and the evolution. In this paper, keograms based on the Crustal Movement Observation Network of China (CMONOC) were used to characterize the irregularities over the area from longitude 85 to 125 °E and latitude 11 to 35 °N in 2014. Keograms were obtained for the rate of TEC index (ROTI) for every 0.5 degree longitude and 30 min universal time pixel. The results showed that the occurrence rate of irregularities in 2014 was high in the equinox months and December, and lowest in June. In equinox months the irregularities often appeared after sunset. In March the irregularities usually had long lifetime of ~ 5–7 h and ~ 5 degrees apparent longitudinal width. The long lifetime usually was accompanied by obvious eastward drift of ~ 100 m/s and large vertical ROTI (vROTI). In September the irregularities had weaker ROTI and shorter lifetime than those in March. The irregularities in the 2 equinox months should be related to the equatorial plasma bubbles (EPBs). In June, they appeared ~ 2–3 h later than those in equinoxes and drifted westward. The summer irregularities had weakest ROTI and their latitude was ~ 30 °N, much higher than those in equinoxes. In December, the irregularities were discrete patches with a longitudinal width of ~ 2 degrees and short lifetime of ~ 2 h. Unlike the equatorial irregularities in equinox months which are part of equatorial plasma bubbles, the solstice irregularities mainly appear to be a local phenomenon.Graphical

Establishment of iGMAST based on spaceborne atomic clocks by optimizing Kalman plus weights algorithm

Highly stable time reference is fundamental and significant for positioning, navigation and timing. The high-precision products generated by the international Global Navigation Satellite System Monitoring and Assessment Service (iGMAS) are currently based on the Global Positioning System time scale (GPST); however, the daily GPST calibration process of iGMAS can introduce daily discontinuity that affects product stability and limits the accuracy of time and frequency transmissions. We aim to establish an internal time reference for iGMAS in this study, to make the products more independent and stable. Firstly, we optimize the commonly used Kalman Plus Weights (KPW) algorithm by adding an exponential filter. The feasibility of the exponential filter to the KPW algorithm is analyzed in detail. Based on the optimized KPW algorithm, we then select 20 satellite-borne atomic clocks with better stability from the different GNSS systems to generate the free iGMAS time scale (iGMAST). After that, we steer the free iGMAST to Coordinated Universal Time (UTC). Finally, the performance of steered iGMAST and GPST are compared and analyzed. The results validate that the optimized KPW algorithm can improve the short-term stability of the time scale by an average of about 16 %. As a consequence, the stability of the established free iGMAST is better than that of a single atomic clock. For the steering process, the steering error of the iGMAST is controlled within ± 4 ns. On the whole, comparing to the GPST, the stability of the steered iGMAST is better when the averaging time is within the range of 2–40 days. For different averaging times, the stability of iGMAST is almost equivalent to that of GPST.

Beyond Settler Time: Temporal Sovereignty and Indigenous Self-Determination

Beyond Settler Time: Temporal Sovereignty and Indigenous Self-Determination

UTC Synchronized Signal Generation for Synchrophasors and Sampled Values Measurements

This article describes two methods and circuits for generation of a signal synchronized to the Coordinated Universal Time (UTC) time scale. The signal is used as a sampling clock for a synchrophasor and Sampled Values generation. Both methods use a PPS (Pulse Per Second) pulse as a synchronization signal. In the first method, the synchronization procedure is implemented entirely in a Field Programmable Gate Array (FPGA) device. The second method uses a microcontroller and a Temperature Compensated Voltage Controlled Crystal Oscillator (TCVCXO). The common feature of the presented methods is that they are cost effective and use a minimal number of components. This paper presents the implementation details of both methods as well as the measurement results, which show that the accuracy of the synchronized signals in both procedures makes them suitable for use in synchrophasors and sampled values measurements.

Variability of f_o E in Relation to the Solar Indices (R_z and F_(10.7) ) at the Equatorial Ionosphere (Ouagadougou Station)

The correlation coefficients between the critical frequency of the ionosphere E-layer ( foE )and the solar radio flux have not been formally evaluated at the Ouagadougou station. The purpose of this paper is to conduct a study on the variability of the critical frequency of ionosphere E-layer with the solar radio flux (F10.7) and sunspot number (Rz) at the Ouagadougou station. The Ouagadougou station is located at the equatorial ionosphere whose coordinates are: lat: 12.5°N; long: 358.5°E; dip 1.5. Moreover, the local time is equal to the universal time (LT=UT). We worked on the solar cycles 21 and 22 (SC21 and SC22) considering their different phases (minimum, increasing, maximum, and decreasing). The values of foE taken into account are those measured at noon (12:00 LT). The results show a good correlation between foE and Rz, and between foE and F10.7. Thus, the correlation coefficient evaluated between foE and Rz is 0.96 at SC21 and 0.93 at SC22, and between foE and F10.7 is 0.95 at SC21 and 0.93 at SC22. We subsequently compared foE of the two solar cycles for the same phase. The calculated deviation between the minimum of SC21 and SC22 is 4.46%. We then find a very small variation of foE from a solar cycle to another at the minimum phase, and this is also verified at the other phases.

UTC and GNSS system time access using PPP with broadcast ephemerides

The application of precise point positioning with broadcast ephemerides (PPP-BCE) is discussed as an alternative to the established all-in-view technique for multi-GNSS time transfer. It combines the use of broadcast ephemerides with low-noise carrier-phase observations for accessing GNSS system time scales and Coordinated Universal Time (UTC) with improved precision, and can be employed on stationary as well as mobile receivers in offline or real-time analyses. Using calibrated timing receivers, the method is shown to provide estimates of the GNSS-to-GNSS time offsets (XYTOs) with an accuracy at the 2 ns level. In the absence of prior calibrations, 0.5 ns consistency across different stations is achieved for GPS, Galileo, and BeiDou-3 after adjustment of systematic biases in comparison with calibrated reference stations or broadcast XYTO values. Furthermore, access to GNSS-specific UTC realizations can be obtained through predictions of the UTC offset from GNSS system time as provided in the broadcast ephemerides of individual constellations. The overall quality of the PPP-BCE-derived receiver clock offsets from UTC is assessed using calibrated receivers at various timing laboratories along with BIPM-provided UTC-UTC(k) measurements. Over the 1.5 years covered in the study, an accuracy of 1.8 ns for GPS and 2.5 ns for Galileo is demonstrated. For BeiDou, a slightly worse accuracy of 3 ns is obtained for a single timing laboratory over 9 months.

On the relation between completely bounded and (1,cb)-summing maps with applications to quantum XOR games

In this work we show that, given a linear map from a general operator space into the dual of a C⁎-algebra, its completely bounded norm is upper bounded by a universal constant times its (1,cb)-summing norm. This problem is motivated by the study of quantum XOR games in the field of quantum information theory. In particular, our results imply that for such games entangled strategies cannot be arbitrarily better than those strategies using one-way classical communication.

Using Daylight Saving Time Clock Changes to Study the Impact of Meteorology on Air Pollution

Implementation of Daylight Savings Time (DST) started in various jurisdictions during the first half of the 20th century. Much debate on the merits of the twice-yearly change in the official local time has ensued since then regarding energy usage, sleep patterns, health outcomes, traffic safety, etc. The DST switch in the official time abruptly shifts anthropogenic emissions that are related to human activities relative to the Coordinated Universal Time (UTC) but does not affect meteorological processes that disperse them, which day-to-day variability is affected by longer time scales. Here, we utilized the DST clock changes as a repeating biannual experiment to study the impact of meteorology on air pollution. We analyzed traffic volume data and up to 20 years of nitrogen oxides (NOx), fine particulate matter (PM2.5), ozone (O3) and carbon monoxide (CO) concentrations, observed at different air quality monitoring (AQM) stations in Israel, demonstrating a clear and significant impact of the daily meteorological cycle on traffic related air pollution (TRAP). In particular, traffic emissions are prerequisite for TRAP, but meteorology was found to dominate the daily patterns of the NOx, O3 and CO concentration fields in the study area. On the other hand, the impact of vehicle emissions on PM2.5 concentrations seems to be very small. Our results highlight the multiscale interplay between pollutant emissions and dispersion processes, especially for pollutants that are emitted near the surface. We demonstrate that while DST clock changes do not affect the emissions intensity, nor the meteorological processes vigor, they do shift human activity-related emissions with respect to the DST-blind dispersion processes. This results in short-term effects on primary traffic-related pollutant concentrations that cancel out over the day, and a consistent yet small effect on secondary traffic-related pollutant concentrations (O3).

Evaluation of Asia-Europe TWSTFT Links Using the Express-80 Satellite

Two-way satellite time and frequency transfer (TWSTFT) is extensively used by the Bureau International des Poids et Mesures (BIPM) in the calculation of coordinated universal time (UTC). The Asia-Europe TWSTFT links using the Express-80 satellite were reestablished in June 2021. This paper uses monthly measurements to evaluate the time comparison performance of the Asia-Europe TWSTFT network. We select TWSTFT data for analysis on the long and short baselines over the same period, respectively. Since the TWSTFT link has not been calibrated, we take the GPS precise point positioning (PPP) link, independent of TWSTFT, as a reference and align the TWSTFT results with it. Then, the results from the TWSTFT and GPS PPP solutions are compared on the different baselines. Finally, the modified Allan deviation (MDEV) and the double clock difference (DCD) between the TWSTFT link and the GPS PPP link are used to evaluate the performance of the TWSTFT results. The results show that the TWSTFT results are consistent with the results of CPS PPP time transfer, and the frequency stability of TWSTFT links on long and short baselines can reach 3E-15 or better with an averaging time of 1 d. The standard deviation of the DCD results is less than 0.4 ns on different baselines, which ensures the accuracy of the TWSTFT link. The Asia-Europe TWSTFT link can be used for UTC time transfer after calibration.

Universe and Multiverse Transportation Possibilities Using Consciousness and Thought Travelling

Universe and Multiverse Transportation Possibilities Using Consciousness and Thought Travelling