Short Time Delay Research Articles

P0075 - Short time delay between prostate biopsy for prostate cancer assessment and Holmium laser enucleation of the prostate (HoLEP) correlates with worse perioperative outcomes

P0075 - Short time delay between prostate biopsy for prostate cancer assessment and Holmium laser enucleation of the prostate (HoLEP) correlates with worse perioperative outcomes

N2 oxidation kinetics in a ns-pulsed discharge above a liquid electrode

In this work, the kinetics of nitrogen fixation via plasma-induced N2 oxidation in a 10 ns pulsed atmospheric pressure water-contacting discharge sustained in air is investigated. Two pulse regimes, a single pulse and a three-pulse burst of 100 kHz, are considered. The densities of relevant radicals (NO, O) are studied by time- and space-resolved laser-induced fluorescence spectroscopy. It is concluded that in a single pulse mode, O atoms are mainly generated by O2 reacting with electronically excited states of N2 () and are primarily reduced as a result of O3 formation. The O density shows a maximum at ∼100 ns after the plasma pulse with number density of ∼1023 m−3. NO radicals, on the other hand, are primarily formed by reacting with the state (up to ∼1 μs after the pulse) and with OH radicals (up to ∼10’s of μs), peaking at approximately 60 μs with a peak density of ∼1021 m−3. The NO loss pathway is represented by the reversed Zeldovich mechanism at short time delays (∼10’s μs), whereas at longer delays (>100’s of μs) HNO2 and NO2 formation causing NO loss start to be dominant. In the burst mode, the energy efficiency of NO formation decreases despite higher N2 conversion, for which three reasons are suggested: (1) NO removal by the generated after the discharge pulse through the reverse Zeldovich mechanism, (2) NO oxidation via the accumulated O3, (3) pre-ionization induced by high pulse repetition rate (100 kHz) leading to shrinkage of the plasma bulk.

The Time Delay Distribution and Formation Metallicity of LIGO-Virgo’s Binary Black Holes

Abstract We derive the first constraints on the time delay distribution of binary black hole (BBH) mergers using the LIGO-Virgo Gravitational-Wave Transient Catalog. Assuming that the progenitor formation rate follows the star formation rate (SFR), the data favor that 43%–100% of mergers have delay times <4.5 Gyr (90% credibility). Adopting a model for the metallicity evolution, we derive joint constraints for the metallicity-dependence of the BBH formation efficiency and the distribution of time delays between formation and merger. Short time delays are favored regardless of the assumed metallicity dependence, although the preference for short delays weakens as we consider stricter low-metallicity thresholds for BBH formation. For a p(τ) ∝ τ −1 time delay distribution and a progenitor formation rate that follows the SFR without metallicity dependence, we find that τ min < 2.2 Gyr, whereas considering only the low-metallicity Z < 0.3 Z ⊙ SFR, τ min < 3.0 Gyr (90% credibility). Alternatively, if we assume long time delays, the progenitor formation rate must peak at higher redshifts than the SFR. For example, for a p(τ) ∝ τ −1 time delay distribution with τ min = 4 Gyr, the inferred progenitor rate peaks at z > 3.9 (90% credibility). Finally, we explore whether the inferred formation rate and time delay distribution vary with BBH mass.

Challenges in control of COVID-19: short doubling time and long delay to effect of interventions.

Early assessments of the growth rate of COVID-19 were subject to significant uncertainty, as expected with limited data and difficulties in case ascertainment, but as cases were recorded in multiple countries, more robust inferences could be made. Using multiple countries, data streams and methods, we estimated that, when unconstrained, European COVID-19 confirmed cases doubled on average every 3 days (range 2.2–4.3 days) and Italian hospital and intensive care unit admissions every 2–3 days; values that are significantly lower than the 5–7 days dominating the early published literature. Furthermore, we showed that the impact of physical distancing interventions was typically not seen until at least 9 days after implementation, during which time confirmed cases could grow eightfold. We argue that such temporal patterns are more critical than precise estimates of the time-insensitive basic reproduction number R0 for initiating interventions, and that the combination of fast growth and long detection delays explains the struggle in countries' outbreak response better than large values of R0 alone. One year on from first reporting these results, reproduction numbers continue to dominate the media and public discourse, but robust estimates of unconstrained growth remain essential for planning worst-case scenarios, and detection delays are still key in informing the relaxation and re-implementation of interventions.This article is part of the theme issue ‘Modelling that shaped the early COVID-19 pandemic response in the UK’.

Evolution of neutron capture elements in dwarf galaxies

ABSTRACT We study the evolution of europium (Eu) and barium (Ba) abundances in Local Group dwarf spheroidal and ultrafaint dwarf galaxies by means of detailed chemical evolution models and compare our results with new sets of homogeneous abundances. The adopted models include gas infall and outflow and have been previously tested. We investigate several production scenarios for r-process elements: merging neutron stars and magnetorotational-driven supernovae. Production of Ba through the main s-process acting in low- and intermediate-mass stars is considered as well. We also test different sets of nucleosynthesis yields. For merging neutron stars we adopt either a constant and short delay time for merging or a delay time distribution function. Our simulations show that (i) if r-process elements are produced only by a quick source, it is possible to reproduce the [Eu/Fe] versus [Fe/H], but those models fail in reproducing the [Ba/Fe] versus [Fe/H]. (ii) If r-process elements are produced only with longer delays the opposite happens. (iii) If both a quick source and a delayed one are adopted, such as magnetorotational-driven supernovae and merging neutron stars with a delay time distribution, the [Eu/Fe] abundance pattern is successfully reproduced, but models still fail in reproducing the [Ba/Fe]. (iv) On the other hand, the characteristic abundances of Reticulum II can be reproduced only if both the Eu and the r-process fraction of Ba are produced on short and constant time delays during a single merging event. We discuss also other possible interpretations, including an inhomogeneous mixing of gas that might characterize this galaxy.

Emissions in short-gated ns/ps/fs-LIBS for fuel-to-air ratio measurements in methane-air flames.

A study of short-gated 10 nanosecond (ns), 100 picosecond (ps), and 100 femtosecond (fs) laser induced breakdown spectroscopy (LIBS) was conducted for fuel-to-air ratio (FAR) measurements in an atmospheric Hencken flame. The intent of the work is to understand which emission lines are available near the optical range in each pulse width regime and which emission ratios may be favorable for generating equivalence ratio calibration curves. The emission spectra in the range of 550-800 nm for ns-LIBS and ps-LIBS are mostly similar with slightly elevated atomic oxygen lines by ps-LIBS. Spectra from fs-LIBS show the lowest continuum background and prominent individual atomic lines, though have significantly weaker ionic emission from nitrogen. A qualitative explanation based on assumed local thermodynamic equilibrium and electron temperatures calculated by the ${{\rm{N}}_{\rm{II}}}({{565}}\;{\rm{nm}})$ and ${{\rm{N}}_{\rm{II}}}({{594}}\;{\rm{nm}})$ emissions is presented. In studying line emission ratios for FAR calculation, it is found that ${{\rm{H}}_\alpha}({{656}}\;{\rm{nm}})/{{\rm{N}}_{\rm{II}}}({{568}}\;{\rm{nm}})$ is best for FAR measurements with ns-LIBS and remains viable for ps-LIBS, while ${{\rm{H}}_\alpha}({{656}}\;{\rm{nm}})/{{\rm{O}}_{\rm I}}({{777}}\;{\rm{nm}})$ is optimal for the ps-LIBS and fs-LIBS cases. Due to low continuum background and short time delay for spectra collection, fs-LIBS is very promising for high-speed FAR measurements using short-gated LIBS.

Non‐isothermal gas‐assisted displacement of viscous Newtonian fluids at high capillary number in gas‐assisted injection molding

AbstractGas‐assisted injection molding is a polymer processing technology in which a penetrating gas bubble hollows out a plastic part as it cools and solidifies within a mold. In this study, non‐isothermal gas injection experiments at high capillary number illustrate the effects of delay time in gas injection, tube diameter, capillary number, and temperature‐sensitive fluid viscosity and flow activation energy on coating thickness. Experiments with polybutene H‐300 and Dow Corning silicon oil (DC‐200) in stainless steel tubing (1.27 and 0.635 cm) demonstrated fractional coverage increasing from 0.6 to a maximum in the range of 0.63–0.83 at short delay times, then decaying toward 0.6 at long delay times upon approaching the cooled isothermal state. Further analysis is drawn from simulations based on a simple theoretical model incorporating one‐dimensional heat transfer with convection at the outer surface of the mold, non‐isothermal behavior of the viscous fluid, and radial velocity profiles in the one‐phase fluid flow region. Quantitative agreement is found between experimental and simulated results. Two‐dimensional modeling and simulation methods extend the prior results to illustrate transient axial and radial heat transfer as well as flow behavior with respect to the penetrating gas bubble within the fluid flow region.

The Effect of the Number of Labeled Objects on Novel Referent Selection Across Short and Long Time Delays

ABSTRACT Children often hear many new words in one conversation, and yet word learning research overwhelmingly focuses on how children learn and retrieve the meanings of single words. The current experiment tests how the number of labeled objects affects preschoolers’ novel word referent selection immediately after encoding and after a one-week delay. Seventy 3- to 6-year-olds were exposed to four novel objects. Half of the participants were given novel labels for two of the objects and half were given novel labels for all four. Label-referent mapping was tested with a four alternative forced-choice pointing task both immediately after exposure and one week later. Children performed worse overall after a week delay, replicating past work on novel word retention. While children performed significantly worse overall in the Four-Label condition, exploratory analyses revealed that this effect was driven solely by the second test trial immediately after exposure. Analyses suggest that referent selection is strongly influenced by in-the-moment constraints, such as label salience and pragmatic biases, and that these constraints are strongest immediately after novel word exposure.

Effect of PEMF on Muscle Oxygenation during Cycling: A Single-Blind Controlled Pilot Study

Pulsed electromagnetic fields (PEMFs) are used as non-invasive tools to enhance microcirculation and tissue oxygenation, with a modulatory influence on the microvasculature. This study aimed to measure the acute effect of PEMF on muscle oxygenation and its influence on pulmonary oxygen kinetics during exercise. Eighteen male cyclists performed, on different days, a constant-load exercise in both active (ON) and inactive (OFF) PEMF stimulations while deoxyhemoglobin and pulmonary oxygen kinetics, total oxygenation index, and blood lactate were collected. PEMF enhanced muscle oxygenation, with higher values of deoxyhemoglobin both at the primary component and at the steady-state level. Moreover, PEMF accelerated deoxyhemoglobin on-transition kinetic, with a shorter time delay, time constant, and mean response time than the OFF condition. Lactate concentration was higher during stimulation. No differences were found for total oxygenation index and pulmonary oxygen kinetics. Local application of a precise PEMF stimulation can increase the rate of the muscle O2 extraction and utilization. These changes were not accompanied by faster oxygen kinetics, reduced oxygen slow component, or reduced blood lactate level. It seems that oxygen consumption is more influenced by exercise involving large muscle mass like cycling, whereas PEMF might only act at the local level.

Short Time Delay Between Previous Prostate Biopsy for Prostate Cancer Assessment and Holmium Laser Enucleation of the Prostate Correlates with Worse Perioperative Outcomes

BackgroundNo data are available regarding the impact of time between a previous transrectal prostate biopsy (PB) and holmium laser enucleation of the prostate (HoLEP) on perioperative outcomes. ObjectiveTo evaluate the impact of time from PB to HoLEP on perioperative outcomes. Design, setting, and participantsA total of 172 consecutive patients treated with HoLEP within 12 mo of a single previous transrectal PB at two tertiary centers were included. Outcome measurements and statistical analysisPatients were stratified into two groups according to the median time from PB to HoLEP (namely, ≤6 and >6 mo). The primary outcome was intraoperative complications. Multivariate logistic regressions were used to identify the predictors of intraoperative complications. Linear regressions were used to test the association between the time from PB to HoLEP and intraoperative complications, enucleation efficiency, and enucleation time. Results and limitationsIn total, 93 (54%) and 79 (46%) patients had PB ≤ 6 and >6 mo before HoLEP, respectively. Patients in PB ≤ 6 mo group experienced higher rates of intraoperative complications than those in PB > 6 mo group (14% vs 2.6%, p = 0.04). At multivariable analysis, time between PB and HoLEP was an independent predictor of intraoperative complications (odds ratio: 0.74; 95% confidence interval: 0.6–0.9; p = 0.006). Finally, the risk of intraoperative complications reduced by 1.5%, efficiency of enucleation increased by 4.1%, and enucleation time reduced by 1.7 min for each month passed from PB to HoLEP (all p ≤ 0.006). Selection of patients with only one previous PB represents the main limitation. ConclusionsThe time from PB to HoLEP of ≤6 mo is associated with a higher risk of intraoperative complications, lower enucleation efficacy, and longer enucleation time. Patient summaryPatients with a prostate biopsy (PB) ≤6 mo before holmium laser enucleation of the prostate (HoLEP) had significantly worse outcomes than those with a PB > 6 mo before HoLEP.

Modeling of contactless bubble–bubble interactions in microchannels with integrated inertial pumps

In this study, the nonlinear effect of contactless bubble–bubble interactions in inertial micropumps is characterized via reduced parameter one-dimensional and three-dimensional computational fluid dynamics (3D CFD) modeling. A one-dimensional pump model is developed to account for contactless bubble-bubble interactions, and the accuracy of the developed one-dimensional model is assessed via the commercial volume of fluid CFD software, FLOW-3D. The FLOW-3D CFD model is validated against experimental bubble dynamics images as well as experimental pump data. Precollapse and postcollapse bubble and flow dynamics for two resistors in a channel have been successfully explained by the modified one-dimensional model. The net pumping effect design space is characterized as a function of resistor placement and firing time delay. The one-dimensional model accurately predicts cumulative flow for simultaneous resistor firing with inner-channel resistor placements (0.2L < x < 0.8L where L is the channel length) as well as delayed resistor firing with inner-channel resistor placements when the time delay is greater than the time required for the vapor bubble to fill the channel cross section. In general, one-dimensional model accuracy suffers at near-reservoir resistor placements and short time delays which we propose is a result of 3D bubble-reservoir interactions and transverse bubble growth interactions, respectively, that are not captured by the one-dimensional model. We find that the one-dimensional model accuracy improves for smaller channel heights. We envision the developed one-dimensional model as a first-order rapid design tool for inertial pump-based microfluidic systems operating in the contactless bubble–bubble interaction nonlinear regime.

Short Time Delay Does Not Hinder Haptic Communication Benefits.

Haptic communication, the exchange of force and tactile information during dancing or moving a table together, has been shown to benefit the performance of human partners. Similarly, it could also be used to improve the performance of robots working in contact with a human operator. As we move to more robot integrated workspaces, how common network features such as delay or jitter impact haptic communication need to be better understood. Here using a human-like interactive robotic controller, that has been found to be indistinguishable by humans to human interaction, we evaluate how subjects' performance and perception is altered by varying levels of transmission delay. We find that subjects are able to recognise haptic delay at very small levels within haptic interaction. However, while they are consciously aware of the delay they can only compensate for it up until a certain point, after which they perceive it as the addition of noise/impedance into the system.

Actinide Crystallization and Fission Reactions in Cooling White Dwarf Stars.

The first solids that form as a cooling white dwarf (WD) starts to crystallize are expected to be greatly enriched in actinides. This is because the melting points of WD matter scale as Z^{5/3} and actinides have the largest charge Z. We estimate that the solids may be so enriched in actinides that they could support a fission chain reaction. This reaction could ignite carbon burning and lead to the explosion of an isolated WD in a thermonuclear supernova (SN Ia). Our mechanism could potentially explain SN Ia with sub-Chandrasekhar ejecta masses and short delay times.

Research on Low-Power Main Control Chip Architecture Based on Edge Computing Technology

With the continuous development of the times, chip technology has also been innovated. In order to meet the needs of edge computing networks and data communication networks, it is necessary to make chips with shorter delay time and lower power consumption, which in turn brings challenges to chip architecture design. In the field of chip design, the problem of chip performance has been overcome. In many edge design networks, the core of the design is to allow the chip to meet low power consumption requirements, thereby extending the use time of edge devices. This article conducts research on a low-power master chip architecture to enable it to meet the needs of edge computing networks and enhance product competitiveness.

Direct numerical simulation of turbulent boundary layer premixed combustion under auto-ignitive conditions

In the present work, premixed combustion in a turbulent boundary layer under auto-ignitive conditions is investigated using direct numerical simulation (DNS). The turbulent inflow of the reactive DNS is obtained by temporal sampling of a corresponding inert DNS of a turbulent boundary layer at a location with Reτ= 360, where Reτ is the friction Reynolds number. The reactants of the DNS are determined by mixing the products of lean natural gas combustion and a H2/N2 fuel jet, resulting in a lean mixture of high temperature with a short ignition delay time. In the free stream the reaction front is stabilized at a streamwise location which can be predicted using the free stream velocity U∞ and the ignition delay time τig. Inside the boundary layer, combustion modifies the near-wall coherent turbulent structures considerably and turbulence results in reaction front wrinkling. The combustion modes in various regions were examined based on the results of displacement velocity, species budget and chemical explosive mode analysis (CEMA). It was indicated that flame propagation prevails in the near-wall region and auto-ignition becomes increasingly important as the wall-normal distance increases. The interactions of turbulence and combustion were studied through statistics of reaction front normal vector and strain rate tensor. It was found that the reaction front normal preferentially aligns with the most compressive strain rate in regions where the effects of heat release on the strain rate are minor and with the most extensive strain rate where its effects are significant. Negative correlations between the wall heat flux and flame quenching distance were observed. A new quenching mode, back-on quenching, was identified. It was found that the heat release rate at the wall is the highest when head-on quenching occurs and lowest when back-on quenching occurs.

Design and Construction of Gas Fire Alert System

This research paper aspired to design and develop a gas leakage and fire monitoring and detection alarm system based on SMS. Most fire incidents in houses, schools and factories are caused by gas leakage. Many houses and factories are being destroyed by fire and gas leakage. To prevent the loss of life and properties, preventive measures should be taken, hence this research was conceptualized. The installation of a GF (Gas and Fire) alert system to vulnerable locations may help lessen if not totally eliminate the dangers posed by gas leakage and fire. The GF system was designed and develop to prevent the loss of life and properties caused by gas leakages & fire thus ensuring the safety of life and property. The design of the GF system is composed of hardware and software integrated and programmed to work as gas and fire detector. The programs are coded using embedded C-language. Tests performed on the developed GF system shows excellent response in detecting gas leaks and fire with short time delay. On the other hand, sending of SMS alert shows promising results with few seconds time delay. Also, the network signal of the place of installation affects the performance of the device to send text messages.

Cross-channel contributions to vortex patterns in photoionization by a pair of counter-rotating circularly polarized attosecond pulses

We theoretically investigate the cross-channel contributions to vortex patterns in photoionization of by a pair of left-right circularly polarized attosecond pulses by numerically solving the two-dimensional (2D) time-dependent Schrödinger equation (TDSE). It is found that the contribution of the ionization cross-channel only worked with a short time delay and the ionization cross-channel will lead to the difference in the brightness of the vortex patterns. The sensitivity of the vortex pattern to the time delay can be employed to control the ionized electron distributions by adjusting the time delay between two laser pulses. These phenomena can be explained by the attosecond perturbation ionization theory.

Anisotropic expansion of drifting spin helices in GaAs quantum wells

The drift of electron spin helices in an external in-plane electric field in GaAs quantum wells is studied by means of time-resolved magneto-optical Kerr microscopy. The evolution of the spin distribution measured for different excitation powers reveals that, for short delay times and higher excitation powers, the spin helix drift slows down while its envelope becomes anisotropic. The effect is understood as a local decrease of the electron gas mobility due to electron collisions with nonequilibrium holes within the excitation spot and is reproduced well in the kinetic theory framework. For larger delay times, when the electrons constituting the spin helix and nonequilibrium holes are separated by an electric field, the spin helix drift accelerates and the mobility reaches its unperturbed value again.

Velocity Measurement of Coherent Doppler Sonar Assisted by Frequency Shift, Kalman Filter and Linear Prediction

Velocity is vital information for navigation and oceanic engineering. Coherent Doppler sonar is an accurate tool for velocity measurement, but its use is limited due to velocity ambiguity. Velocity measured by frequency shift has no velocity ambiguity, yet its measurement error is larger than that of coherent Doppler sonar. Therefore, coherent Doppler sonar assisted by frequency shift is used to accurately measure velocity without velocity ambiguity. However, the velocity measured by coherent Doppler sonar assisted by frequency shift is affected by impulsive noise. To decrease the impulsive noise, Kalman filter and linear prediction are proposed to improve the velocity sensing accuracy. In this method, the Kalman filter is used to decrease measurement error of velocity measured by frequency shift, and linear prediction is used to remove the impulsive noise generated by a wrong estimate of the integer ambiguity. Lab-based experiments were carried, and the results have shown that coherent Doppler sonar assisted by frequency shift, Kalman filter and linear prediction can provide accurate and precise velocity with short time delay in a large range of signal to noise ratio.

An Identity Privacy Protection Scheme in LTE-WLAN Heterogeneous Converged Network

Aiming at to avoid the drawbacks of the identity privacy protection scheme in Long Term Evolution-Wireless Local Area Network (LTE-WLAN) heterogeneous converged network proposed by the 3rd Generation Partnership Project (3GPP), an improved scheme based on identity index is proposed to achieve anonymity, untraceability and dynamic identity. Security analysis shows that our proposed scheme can prevent replay attack and man-in-the-middle attack for network layer authentication. The results of comparison with the related schemes show that security and efficiency of our proposed scheme is prior to some other existing ones with low computation cost and short time delay.