bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-endoscopy Barrett’s neoplasia after a negative index endoscopy: a systematic review and proposal for definitions and performance measures in endoscopy
Authors: Desai Madhav , Lieberman David , Srinivasan Sachin , Nutalapati Venkat , Challa Abhishek , Kalgotra Pankush , Sundaram Suneha , Repici Alessandro , Hassan Cesare , Kaminski Michal F. , Sharma Prateek
Published: January 2022

Background A high rate of neoplasia, both high grade dysplasia (HGD) and esophageal adenocarcinoma (EAC) has been reported in Barrett’s esophagus at index endoscopy, but precise rates of post-endoscopy Barrett’s neoplasia (PEBN) are unknown.

Methods A systematic review and meta-analysis was performed examining electronic databases (inception to October 2021) for studies reporting PEBN. Consistent with the definitions of post-colonoscopy colorectal cancer proposed by the World Endoscopy Organization, we defined neoplasia (HGD/EAC) detected at index endoscopy and/or within 6 months of a negative index endoscopy as “prevalent” neoplasia, that detected after 6 months of a negative index endoscopy and prior to next surveillance interval (i. e. 3 years) as PEBN or “interval” neoplasia, and that detected after 36 months from a negative index endoscopy as “incident” neoplasia. The pooled incidence rates and proportions relative to total neoplasia were analyzed.

Results 11 studies (n = 59 795; 61 % men; mean [SD] age 62.3 [3.3] years) met the inclusion criteria. The pooled incidence rates were: prevalent neoplasia 4.5 % (95 %CI 2.2 %–8.9 %) at baseline and an additional 0.3 % (0.1 %–0.7 %) within the first 6 months, PEBN 0.52 % (0.46 %–0.58 %), and incident neoplasia 1.4 % (0.9 %–2.1 %). At 3 years from the index endoscopy, PEBN accounted for 3 % of total Barrett’s neoplasia, while prevalent neoplasia accounted for 97 %.

Conclusion Neoplasia detected at or within 6 months of index endoscopy accounts for most cases of Barrett’s neoplasia (> 90 %). PEBN accounts for ~3 % of cases and can be used for validation in future. This highlights the importance of a high quality index endoscopy in Barrett’s esophagus and the need to establish quality benchmarks to measure endoscopists’ performance.
Effectiveness and Safety of Oral Anticoagulants in the Treatment of Acute Venous Thromboembolism: A Nationwide Comparative Cohort Study in France
Authors: Bertoletti Laurent , Gusto Gaelle , Khachatryan Artak , Quignot Nadia , Chaves Jose , Moniot Audrey , Mokgokong Ruth
Published: January 2022

Introduction Data from clinical trials indicate that direct oral anticoagulants (DOACs) are noninferior and safer than conventional therapy (low-molecular-weight heparin followed by a vitamin K antagonist [VKA]) for treating venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism (PE). This study compared the effectiveness and safety of DOACs and conventional therapy in a real-world setting.

Methods This observational study used French national claims data of adult, treatment-naïve patients diagnosed with VTE (majority PE) who were hospitalized and treated for VTE with a DOAC (apixaban or rivaroxaban) or VKAs during 2013 to 2018. Patients with active cancer were excluded. After propensity score matching for each DOAC-VKA comparison, risks of bleeding, recurrent VTE, and all-cause mortality were compared at 6 months. Cox proportional hazards regression was used to estimate adjusted hazard ratios of the endpoints.

Results A total of 58,137 patients were included (10,775 VKAs, 10,440 apixaban, 36,922 rivaroxaban). Propensity score-matched cohort sizes were 7,503 for apixaban and 9,179 for rivaroxaban. The hazard ratio (95% confidence interval) was significantly lower for apixaban than VKAs for bleeding requiring hospitalization (0.43 [0.32–0.59]), all-cause death (0.61 [0.51–0.74]), and first recurrent VTE (0.67 [0.52–0.85]). The hazard ratio was also significantly lower for rivaroxaban than VKAs for all-cause death (0.63 [0.53–0.74]) but not for bleeding requiring hospitalization (0.86 [0.69–1.07]) or first recurrent VTE (0.91 [0.74–1.13]).

Conclusion Apixaban was associated with superior safety and effectiveness than VKAs. All-cause mortality was lower in both DOACs than VKAs. Our results support recommendations to use DOACs over VKAs for the treatment of VTE.
The BTK Safety Score: A Novel Scoring System for Risk Stratifying Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty
Authors: Wang Kevin Y. , Puvanesarajah Varun , Raad Micheal , Barry Kawsu , Srikumaran Umasuthan , Thakkar Savyasachi C.
Published: January 2022

Selection of appropriate candidates for simultaneous bilateral total knee arthroplasty (si-BTKA) is crucial for minimizing postoperative complications. The aim of this study was to develop a scoring system for identifying patients who may be appropriate for si-BTKA. Patients who underwent si-BTKA were identified in the National Surgical Quality Improvement Program database. Patients who experienced a major 30-day complication were identified as high-risk patients for si-BTKA who potentially would have benefitted from staged bilateral total knee arthroplasty. Major complications included deep wound infection, pneumonia, renal insufficiency or failure, cerebrovascular accident, cardiac arrest, myocardial infarction, pulmonary embolism, sepsis, or death. The predictive model was trained using randomly split 70% of the dataset and validated on the remaining 30%. The scoring system was compared against the American Society of Anesthesiologists (ASA) score, the Charlson Comorbidity Index (CCI), and legacy risk-stratification measures, using area under the curve (AUC) statistic. Total 4,630 patients undergoing si-BTKA were included in our cohort. In our model, patients are assigned points based on the following risk factors: +1 for age ≥ 75, +2 for age ≥ 82, +1 for body mass index (BMI) ≥ 34, +2 for BMI ≥ 42, +1 for hypertension requiring medication, +1 for pulmonary disease (chronic obstructive pulmonary disease or dyspnea), and +3 for end-stage renal disease. The scoring system exhibited an AUC of 0.816, which was significantly higher than the AUC of ASA (0.545; p < 0.001) and CCI (0.599; p < 0.001). The BTK Safety Score developed and validated in our study can be used by surgeons and perioperative teams to risk stratify patients undergoing si-BTKA. Future work is needed to assess this scoring system's ability to predict long-term functional outcomes.
COVID-19 lockdown implementation in Ghana: lessons learned and hurdles to overcome
Authors: Assan Abraham , Hussein Hawawu , Agyeman-Duah David N. K.
Published: January 2022

COVID-19 exacts huge health and economic burdens on the global economy. To minimize spread of the virus, most governments of the wealthiest countries implemented lockdowns—a tough preventive measure. Ghana implemented a partial lockdown of two major cities, then lifted it in few weeks despite rising numbers of cases. This Viewpoint presents perspectives of key stakeholders in the public about lockdown implementation in Ghana. Respondents characterize the lifting of the lockdown as hasty, poorly communicated, and lacking transparency. Most would have preferred a longer lockdown despite the pressures it imposed especially on the urban poor. Participants expressed uncertainty about the health systems' ability to respond to increases in disease transmission and to provide education, engagement, and empowerment needed in communities, but even so would have preferred a longer lockdown. We offer lessons for more effective policy and implementation of lockdowns.
Effect of physical cluster formation on the behavior of correlation functions for a fluid system
Authors: Kaneko Tetsuo
Published: January 2022

Physical cluster formation in a fluid system causes a characteristic dependence of the pair correlation function on the distance r between a specific pair of particles at the liquid–vapor critical point. Its dependence deviates from that expressed by the product of a negative power r−1 and a specific function provided by a Taylor series with respect to positive powers of r. The effects of the physical cluster formation can be estimated by representing the pair correlation function as a sum of two correlation functions; these two correlation functions can be provided as exact solutions for two differential equations that result from a system of two integral equations equivalent to the Ornstein–Zernike equation.
Integral equation models for solvent in macromolecular crystals
Authors: Gray Jonathon G. , Giambaşu George M. , Case David A. , Luchko Tyler
Published: January 2022

The solvent can occupy up to ∼70% of macromolecular crystals, and hence, having models that predict solvent distributions in periodic systems could improve the interpretation of crystallographic data. Yet, there are few implicit solvent models applicable to periodic solutes, and crystallographic structures are commonly solved assuming a flat solvent model. Here, we present a newly developed periodic version of the 3D-reference interaction site model (RISM) integral equation method that is able to solve efficiently and describe accurately water and ion distributions in periodic systems; the code can compute accurate gradients that can be used in minimizations or molecular dynamics simulations. The new method includes an extension of the Ornstein–Zernike equation needed to yield charge neutrality for charged solutes, which requires an additional contribution to the excess chemical potential that has not been previously identified; this is an important consideration for nucleic acids or any other charged system where most or all the counter- and co-ions are part of the “disordered” solvent. We present several calculations of proteins, RNAs, and small molecule crystals to show that x-ray scattering intensities and the solvent structure predicted by the periodic 3D-RISM solvent model are in closer agreement with the experiment than are intensities computed using the default flat solvent model in the refmac5 or phenix refinement programs, with the greatest improvement in the 2 to 4 Å range. Prospects for incorporating integral equation models into crystallographic refinement are discussed.
Experimental scaling laws for the discharge oscillations and performance of Hall thrusters
Authors: Giannetti V. , Piragino A. , Paissoni C. A. , Ferrato E. , Estublier D. , Andreussi T.
Published: January 2022

Low-frequency (5–30 kHz) discharge current oscillations characterize the operation of Hall thrusters and represent a valuable metric not only to monitor the thruster behavior, but also to optimize the thruster performance. Two types of low-frequency oscillation modes are commonly observed: a global “breathing” mode, associated with the propellant ionization, and a local mode, typically characterized by a lower oscillation amplitude and the appearance of azimuthal spokes. The main characteristics of discharge oscillations and the transition between the two oscillation modes vary greatly with the thruster geometry and the operating condition. In this work, we present the results of an experimental campaign carried out on a 20 kW-class thruster prototype, SITAEL’s HT20k, with an exchangeable discharge channel and a magnetic circuit. Three different channel sizes were tested over a wide range of operating conditions and magnetic fields. For each operating point, a high frequency measurement of the discharge current was performed, recording the main characteristics of the oscillations. The data collected were then processed to derive the influence coefficients of each thruster parameter on the discharge current characteristics, as well as their dispersion. Finally, this allowed us to formulate general, data-driven scaling laws for the discharge current salient features, such as oscillation amplitude and dominant frequency. The gathered insight sheds light on the physical processes involved in the thruster discharge. At the same time, the possibility to model with simple functional laws the main oscillatory mode of Hall thrusters offers a unique aid to the optimization of thruster design and the evaluation of thruster performance during life.
Experimental study of the dispersion of cough-generated droplets from a person going up- or downstairs
Authors: Wang Hongping , Li Zhaobin , Liu Yi , Zhu Lixing , Zhou Zhideng
Published: January 2022

The dispersion of cough-generated droplets from a person going up- or downstairs was investigated through a laboratory experiment in a water tunnel. This experiment was carried out with a manikin mounted at inclination angles facing the incoming flow to mimic a person going up or down. Detailed velocity measurements and flow visualization were conducted in the water tunnel experiments. To investigate the influence of the initial position on the motion of particles, a virtual particle approach was adopted to simulate the dispersion of particles using the measured velocity field. Particle clustering, which is caused by the unsteadiness of the flow, was observed in both flow visualization and virtual particle simulation. For the case of going upstairs, particles are concentrated below the person’s shoulder and move downward with a short travel distance. For the case of going downstairs, particles dispersing over the person’s head advect over for a long distance. We also found that the motion of the particles is closely related to the initial position. According to the results in this study, suggestions for the prevention of respiratory infectious disease are made.
A novel response surface method for structural reliability
Authors: Yang Ruigang , Li Wenzhao , Liu Yuzhen
Published: January 2022

The response surface method is a common method to solve structural reliability problems. The core principle of this method is the approximation of the actual limit state function using the response surface function for subsequent analytical calculations. The existing response surface method for structural reliability has poor approximation ability and waste of the actual limit state function of the experimental points. These problems lead to low computational efficiency and inability to satisfy high-precision engineering requirements. This paper proposes a novel response surface method for structural reliability. The efficiency and accuracy are improved by the new experimental point selection strategy of the proposed method. This method has the following obvious advantages: the experimental point is close to the actual limit state function, the actual number of calculations is reduced, and the effect of the constructed response surface function approximation is improved. In addition, the single response surface function form is not used in the proposed method to improve the iterative efficiency. Compared with other response surface methods for structural reliability, three calculation examples prove the accuracy and efficiency of the proposed method.
A comparative analysis of the evolution of compositional and entropy waves in turbulent channel flows
Authors: Rahmani E. , Fattahi A. , Karimi N. , Hosseinalipour S. M.
Published: January 2022

Indirect combustion noise, as an important source of noise in gas turbines, was traditionally attributed solely to entropy waves. In recent years, compositional waves were introduced as another contributor to indirect combustion noise. Nonetheless, unlike that of entropy waves, the annihilation of compositional waves by the mean flow has remained largely unexplored. Hence, the current numerical study analyzes the spatiotemporal evolution of different components of compositional waves and compares them with the decay of entropy waves. A convecting wave, including a mixture of combustion products at elevated temperature, is introduced at the inlet of a simple channel. This allows simultaneous analysis of entropy and compositional waves. The passage of these along the channel is modeled using a large eddy simulation, and the annihilation of the waves' components is examined in the frequency domain. It is shown that the turbulence level of the mean flow and convective heat transfer on the walls can both result in a considerable wave deterioration. However, the effects of heat losses from the channel walls are found to be stronger than that of turbulence intensity. Importantly, as the wave is convected, the chemical potential function remains coherent for most of the channel length, and deterioration of the compositional wave majorly ensues from the mixture fraction gradient. The results indicate that, overall, the compositional sources feature 10%–20% more dissipation in comparison with the entropic sources. Therefore, compositional waves are less likely to survive the flow and generate noise.
Hydrodynamic performance of an unconstrained flapping swimmer with flexible fin: A numerical study
Authors: Wu Buchen , Shu Chang , Wan Minping , Wang Yan , Chen Shiyi
Published: January 2022

Flexible tail fins are commonly found in undulatory swimmers which can propel freely in omni-direction with flapping-wing-based propulsion. In this work, the hydrodynamic performance of an unconstrained flapping foil equipped with a flexible tail fin at different length is investigated numerically. As the fin length Lfin changes from 0.2c to c with c being the cord length, the propelling speed of the system first increases and then decreases after maximum propelling speed is achieved when the fin length is 0.8c. There are two kinds of wake vortical structures observed with bending stiffness kb = 2.0: (i) the regular reverse Bénard–von Kármán vortex configuration for foil with short fin and (ii) the aligned vortices with two-layered street at downstream for foil with long fin (Lfin≥ 0.6c). Control volume analysis reveals that for both types of vortical structures, the time-averaged thrust force is mainly related to the momentum flux contribution from the downstream face. Besides, the wake symmetry of a pitching foil with flexible tail fin is sensitive to the vertical phase velocity of vortices, where it can be used to predict whether the wake symmetry of the unconstrained system is preserved. Moreover, the bending stiffness effectively affects the hydrodynamic performance, and the breaking of wake symmetry greatly reduces the propulsive efficiency. The results obtained shed some new light on the role of flexible structures in the self-propulsive biological system and furthered our understanding of flexible self-propulsion system.
Fluid-like representation of Fickian diffusion
Authors: Heifetz E. , Zucker S.
Published: January 2022

Here, we show that the fundamental Fickian process of diffusion can be equivalently described by a pressureless, compressible, and irrotational flow dynamics, whose effective force is governed by the divergence of the viscous stress tensor. This brings together the seemingly unrelated processes of mass and momentum transports.
Effects of low and high viscous product on Kelvin–Helmholtz instability triggered by A+B→C type reaction
Authors: Maharana Surya Narayan , Mishra Manoranjan
Published: January 2022

The dynamics of the Kelvin–Helmholtz (K–H) instability triggered by a non-linear second order A+B→C type reaction is analyzed through direct numerical simulations. This paper aims to understand the chemo-hydrodynamic K–H instability when the chemical reaction decreases or increases the viscosity gradient at the reactive interface. Thus, we consider the viscosity of the obtained product C is to be different from both the iso-viscous reactants A and B. It is observed that for both the cases of less and more-viscous product C, K–H roll-ups occur at the reactive interface and hence various flow features are compared for both of these scenarios. Moreover, depending on the product's viscosity, the flow-directed K–H roll-ups occur either at A–C interface or C–B interface. Strikingly the number of K–H roll-ups at the reactive interface is more when the product is less viscous and full vortex completion of K–H roll-ups is noticed. It is demonstrated that even for a significantly large Damköhler number (high rate of reaction), the K–H roll-ups may not occur at the reactive front. Thus, a favorable log-mobility ratio (Mc) having a greater magnitude than the critical log-mobility ratio (Mccrit) is required to trigger the K–H instability within a desirable time for both the cases of Mc < 0 and Mc > 0. Moreover, asymmetric onset dynamics are encountered with respect to Mc = 0 axis.
Tiling a tubule: how increasing complexity improves the yield of self-limited assembly
Authors: Videbæk Thomas E , Fang Huang , Hayakawa Daichi , Tyukodi Botond , Hagan Michael F , Rogers W Benjamin
Published: January 2022

The ability to design and synthesize ever more complicated colloidal particles opens the possibility of self-assembling a zoo of complex structures, including those with one or more self-limited length scales. An undesirable feature of systems with self-limited length scales is that thermal fluctuations can lead to the assembly of nearby, off-target states. We investigate strategies for limiting off-target assembly by using multiple types of subunits. Using simulations and energetics calculations, we explore this concept by considering the assembly of tubules built from triangular subunits that bind edge to edge. While in principle, a single type of triangle can assemble into tubules with a monodisperse width distribution, in practice, the finite bending rigidity of the binding sites leads to the formation of off-target structures. To increase the assembly specificity, we introduce tiling rules for assembling tubules from multiple species of triangles. We show that the selectivity of the target structure can be dramatically improved by using multiple species of subunits, and provide a prescription for choosing the minimum number of subunit species required for near-perfect yield. Our approach of increasing the system’s complexity to reduce the accessibility of neighboring structures should be generalizable to other systems beyond the self-assembly of tubules.
Piezoelectric unimorph and bimorph cantilever configurations: Design guidelines and strain assessment
Authors: Giri Abhijeet M , Ali S F , Arockiarajan A
Published: January 2022

Multi-stable configurations of piezoelectric harvester are quite successful in achieving the two important goals, the broadband frequency response and large orbit oscillations exhibiting periodic, multi-periodic, and chaotic solutions. However, in the quest of achieving large amplitude broadband frequency response, assessment of induced strain levels considering the limits on the strain in piezoelectric material has received minimal attention. In this context, the investigation presents analytical formulation for the assessment of induced strain and voltage(s) in piezoelectric unimorph and bimorph cantilevers. The formulation quantifies not only the induced voltages in individual piezoelectric layers of a bimorph, but also the equivalent voltages in parallel and series connection modes, respectively. Also, while computing the induced voltage in the first piezoelectric layer, the contribution from the induced voltage of second piezoelectric layer to the acting bending moment is captured in the formulation. The formulations are validated through the experiments and results from the literature. Further, we have applied two practically useful normalization schemes, the

t

p

- and

t

t

-normalizations to the analytical expressions. Using the two normalization schemes, influences of variation of substrate and adhesive layer thicknesses, elastic moduli of layers, and substrate-to-composite length fraction are visualized and discussed. Based on the results, summarized guidelines for design and selection of geometric and material parameters are presented, which may also be applicable for other sensing and actuation applications. At last, practically suitable ranges and optimum values for the normalized design variables are proposed.
Boosting engine performance with Bose–Einstein condensation
Authors: Myers Nathan M , Peña Francisco J , Negrete Oscar , Vargas Patricio , De Chiara Gabriele , Deffner Sebastian
Published: January 2022

At low-temperatures a gas of bosons will undergo a phase transition into a quantum state of matter known as a Bose–Einstein condensate (BEC), in which a large fraction of the particles will occupy the ground state simultaneously. Here we explore the performance of an endoreversible Otto cycle operating with a harmonically confined Bose gas as the working medium. We analyze the engine operation in three regimes, with the working medium in the BEC phase, in the gas phase, and driven across the BEC transition during each cycle. We find that the unique properties of the BEC phase allow for enhanced engine performance, including increased power output and higher efficiency at maximum power.
Dynamics of matter-wave solitons in three-component Bose-Einstein condensates with time-modulated interactions and gain or loss effect
Authors: Yang Yajie , Dong Ying
Published: January 2022

The gain or loss effect on the dynamics of the matter-wave solitons in three-component Bose–Einstein condensates with time-modulated interactions trapped in parabolic external potentials are investigated analytically. Some exact matter-wave soliton solutions to the three-coupled Gross–Pitaevskii equation describing the three-component Bose–Einstein condensates are constructed by similarity transformation. The dynamical properties of the matter-wave solitons are analyzed graphically, and the effects of the gain or loss parameter and the frequency of the external potentials on the matter-wave solitons are explored. It is shown that the gain coefficient makes the atom condensate to absorb energy from the background, while the loss coefficient brings about the collapse of the condensate.
Dynamical behavior of cardiac conduction system under external disturbances: simulation based on microcontroller technology
Authors: Fonkou R F , Louodop Patrick , Talla P K
Published: January 2022

The heart rhythm is one of the most interesting aspects of the dynamic behavior of biological systems. Understanding heart rhythms is essential in the dynamic analysis of the heart. Each type of dynamic behaviour can describe normal or pathological physiology. The heart is made up of nodes ranging from SA node (natural pacemaker) to Purkinje fibers. The electric current originates in the sinus node and travels through the heart until it reaches the Purkinje fibers, causing after its passage through each of the nodes a heartbeat thus constituting the electrocardiogram (ECG). Since the origin of the electric current is the sinus node, in this article we study numerically and experimentally by microcontroller the influence of the sinus node on the propagation of electric current through the heart. A study of the sinus node in its autonomous state shows us that in their coupled state, the nodes of the heart qualitatively reproduce the time series of the action potential of this latter, which leads to the recording of the ECG. A study when the sinus node is subjected to periodic pulsed excitation

E

1

(
t
)

=
k
P

(
t
)

,

assumed to come from blood pressure, with

P

(
t
)

the blood pressure, shows that for some selected frequencies, it is found that the nodes of the heart and the ECG exhibit responses having the same shape and the same frequencies as those of the pulsatile blood pressure. This suggests the possibility of using such a conversion and excitation mechanism to replicate the functioning of cardiac conduction system. The chaotic analysis of the sinus node subjected to a sinusoidal type disturbance

E

0

sin

(
ω
t
)

is also presented, it shows that in its chaotic state, the nodes of the heart, as well as the ECG, provide very high frequency signals. This requires the control of the sinus node (natural pacemaker) in such a situation.
Investigating non-Gaussianity in Cosmic Microwave Background temperature maps using spherical harmonic phases
Authors: Kumar Yadav Sarvesh , Saha Rajib
Published: January 2022

In the era of precision cosmology, accurate estimation of cosmological parameters is based upon the implicit assumption of the Gaussian nature of Cosmic Microwave Background (CMB) radiation. Therefore, an important scientific question to ask is whether the observed CMB map is consistent with Gaussian prediction. In this work, we extend previous studies based on CMB spherical harmonic phases (SHP) to examine the validity of the hypothesis that the temperature field of the CMB is consistent with a Gaussian random field (GRF). The null hypothesis is that the corresponding CMB SHP are independent and identically distributed in
terms of a uniform distribution in the interval [0, 2π] [1,2]. We devise a new model-independent method where we use ordered and non-parametric Rao's statistic, based on sample arc-lengths to comprehensively test uniformity and independence of SHP for a given ℓ mode and independence of nearby ℓ mode SHP. We performed our analysis on the scales limited by spherical harmonic modes ≤ 128, to restrict ourselves to signal-dominated regions. To find the non-uniform or dependent sets of SHP, we calculate the statistic for the data and 10000 Monte Carlo simulated uniformly random sets of SHP and use 0.05 and 0.001 α levels to distinguish between statistically significant and highly significant detections. We first establish the performance of our method using simulated Gaussian, non-Gaussian CMB temperature maps, along with observed non-Gaussian 100 and 143 GHz Planck channel maps. We find that our method, performs efficiently and accurately in detecting phase correlations generated in all of the non-Gaussian simulations and observed foreground contaminated 100 and 143 GHz Planck channel temperature maps. We apply our method on Planck satellite mission's final released CMB temperature anisotropy maps- COMMANDER, SMICA, NILC, and SEVEM along with WMAP 9 year released ILC map. We report that SHP corresponding to some of the m-modes are non-uniform, some of the ℓ mode SHP and neighboring mode pair SHP are correlated in cleaned CMB maps. The detection of non-uniformity or correlation in the SHP indicates the presence of non-Gaussian signals in the foreground minimized CMB maps.
Light scalars in neutron star mergers
Authors: Bhupal Dev P.S. , Fortin Jean-François , Harris Steven P. , Sinha Kuver , Zhang Yongchao
Published: January 2022

Due to their unique set of multimessenger signals, neutron star mergers have emerged as a novel environment for studies of new physics beyond the Standard Model (SM). As a case study, we consider the simplest extension of the SM scalar sector involving a light CP-even scalar singlet S mixing with the SM Higgs boson. These S particles can be produced abundantly in neutron star mergers via the nucleon bremsstrahlung process. We show that the S particles may either be trapped in or stream freely out of the merger remnant, depending on the S mass, its mixing with the SM Higgs boson, and the temperature and baryon density in the merger. In the free-streaming region, the scalar S will provide an extra channel to cool down the merger remnant, with cooling timescales as small as 𝒪(ms). On the other hand, in the trapped region, the Bose gas of S particles could contribute a larger thermal conductivity than the trapped neutrinos in some parts of the parameter space, thus leading to faster thermal equilibration than expected. Therefore, future observations of the early postmerger phase of a neutron star merger could effectively probe a unique range of the S parameter space, largely complementary to the existing and future laboratory and supernova limits. In view of these results, we hope the merger simulation community will be motivated to implement the effects of light CP-even scalars into their simulations in both the free-streaming and trapped regimes.
Nonlinear electrodynamics effects
on the black hole shadow,
deflection angle, quasinormal modes
and greybody factors
Authors: Okyay M. , Övgün A.
Published: January 2022

In this paper, we discuss the effects of nonlinear electrodynamics (NED) on non-rotating black holes, parametrized by the field coupling parameter β and magnetic charge parameter P in detail. Particularly, we survey a large range of observables and physical properties of the magnetically charged black hole, including the thermodynamic properties, observational appearance, quasinormal modes and absorption cross sections. Initially, we show that the NED black hole is always surrounded by an event horizon and any magnetic charge is permissible. We then show that the black hole gets colder with increasing charge. Investigating the heat capacity, we see that the black hole is thermally stable between points of phase transition. Introducing a generalized uncertainty principle (GUP) with a quantum gravity parameter λ extends the range of the stable region, but the effect on temperature is negligible. Then we compute the deflection angle at the weak field limit, by the Gauss-Bonnet theorem and the geodesic equation, and find that even at the first order, the magnetic charge has a contribution due to the “field mass” term. Small changes of the charge contributes greatly to the paths of null geodesics due to the P
2 dependence of the horizon radius. Using a ray-tracing code, we simulate the observational appearance of a NED black hole under different emission profiles, thin disk and spherical accretion. We find that the parameter P has a very strong effect on the observed shadow radius, in agreement with the deflection angle calculations. We finally consider quasinormal modes under massless scalar perturbations of the black hole and the greybody factor. We find that the charge introduces a slight difference in the fundamental frequency of the emitted waveform. We find that the greybody factor of the NED black hole is strongly steepened by the introduction of increasing charge. To present observational constrains, we show that the magnetic charge of the M87* black hole is between 0 ≤ P ≤ 0.024 in units of M, in agreement with the idea that real astrophysical black holes are mostly neutral. We also find that LIGO/VIRGO and LISA could detect NED black hole perturbations from BHs with masses between 5 M
☉ and 8.0 · 108
M
☉. We finally show that for black holes with masses detected with LIGO so far, charged NED black holes would deviate from Schwarzschild by 5∼10 Hz in their fundamental frequencies.
Fermionic vacuum polarization
around a cosmic string in compactified
AdS spacetime
Authors: Bellucci S. , Oliveira dos Santos W. , Bezerra de Mello E.R. , Saharian A.A.
Published: January 2022

We investigate topological effects of a cosmic string and compactification
of a spatial dimension on the vacuum expectation value (VEV) of the
energy-momentum tensor for a fermionic field in (4+1)-dimensional locally
AdS spacetime. The contribution induced by the compactification is
explicitly extracted by using the Abel-Plana summation formula. The mean
energy-momentum tensor is diagonal and the vacuum stresses along the
direction perpendicular to the AdS boundary and along the cosmic string are
equal to the energy density. All the components are even periodic functions
of the magnetic fluxes inside the string core and enclosed by compact
dimension, with the period equal to the flux quantum. The vacuum energy
density can be either positive or negative, depending on the values of the
parameters and the distance from the string. The topological contributions
in the VEV of the energy-momentum tensor vanish on the AdS boundary. Near
the string the effects of compactification and gravitational field are weak
and the leading term in the asymptotic expansion coincides with the
corresponding VEV in (4+1)-dimensional Minkowski spacetime. At large
distances, the decay of the cosmic string induced contribution in the vacuum
energy-momentum tensor, as a function of the proper distance from the
string, follows a power law. For a cosmic string in the Minkowski bulk and
for massive fields the corresponding fall off is exponential. Within the
framework of the AdS/CFT correspondence, the geometry for conformal field
theory on the AdS boundary corresponds to the standard cosmic string in
(3+1)-dimensional Minkowski spacetime compactified along its axis.
Potential reconstruction from general power spectrum in single-field inflation
Authors: Choi Ki-Young , Gong Jinn-Ouk , Kang Su-beom , Nath Raveendran Rathul
Published: January 2022

We suggest a new method to reconstruct, within canonical single-field inflation, the inflaton potential directly from the primordial power spectrum which may deviate significantly from near scale-invariance. Our approach relies on a more generalized slow-roll approximation than the standard one, and can probe the properties of the inflaton potential reliably. We give a few examples for reconstructing potential and discuss the validity of our method.
Energy reconstruction in a liquid argon calorimeter cell using convolutional neural networks
Authors: Polson L. , Kurchaninov L. , Lefebvre M.
Published: January 2022

The liquid argon ionization current in a sampling calorimeter cell can be analyzed to determine the energy of detected particles. In practice, experimental artifacts such as pileup and electronic noise make the inference of energy from current a difficult process. The beam intensity of the Large Hadron Collider will be significantly increased during the Phase-II long shut-down of 2025–2027. Signal processing techniques that are used to extract the energy of detected particles in the ATLAS detector will suffer a significant loss in performance under these conditions. This paper compares the presently used optimal filter technique to convolutional neural networks for energy reconstruction in the ATLAS liquid argon hadronic end cap calorimeter. In particular, it is shown that convolutional neural networks trained with an appropriately tuned and novel loss function are able to outperform the optimal filter technique.
MAGIS-100 environmental characterization and noise analysis
Authors: Mitchell J. , Kovachy T. , Hahn S. , Adamson P. , Chattopadhyay S.
Published: January 2022

We investigate and analyze site specific systematics for the MAGIS-100 atomic interferometry experiment at Fermi National Accelerator Laboratory. As atom interferometers move out of the laboratory environment passive and active mitigation for noise sources must be implemented. To inform the research and development of the experiment design, we measure ambient temperature, humidity, and vibrations of the installation site. We find that temperature fluctuations will necessitate enclosures for critical subsystems and a temperature controlled laser room for the laser system. We also measure and analyze the vibration spectrum above and below ground for the installation site. The seismic vibration effect of gravity gradient noise is also modeled using input from a low-noise seismometer at multiple locations and a mitigation scheme is studied using a stochastic simulation and characterized by a suppression factor.
Associations between air pollution and psychiatric symptoms in the Normative Aging Study
Authors: Qiu Xinye , Danesh-Yazdi Mahdieh , Weisskopf Marc , Kosheleva Anna , Spiro Avron , Wang Cuicui , Coull Brent A , Koutrakis Petros , Schwartz Joel D
Published: January 2022

Environmental risk factors for psychiatric health are poorly identified. We examined the association between air pollution and psychiatric symptoms, which are often precursors to the development of psychiatric disorders. This study included 570 participants in the US Veterans Administration (VA) Normative Aging Study (NAS) and 1114 visits (defined as an onsite follow-up at the VA with physical examination and questionnaires) from 2000 to 2014 with information on the brief symptom inventory (BSI) to assess their psychiatric symptom levels. Differences in the three BSI global measures (global severity index (GSI), positive symptom distress index (PSDI) and positive symptom total (PST)) were reported per interquartile (IQR) increase of residential address-specific air pollutants levels (fine particulate matter—PM2.5, ozone—O3, nitrogen dioxide—NO2) at averages of one week, four weeks, eight weeks and one year prior to the visit, using generalized additive mixed effects models. We also evaluated modification by neighborhood factors. On average, among the NAS sample (average age: 72.4 years (standard deviation: 6.7 years)), an IQR increase in one and four week averages of NO2 before a visit was associated with a PSDI T score (indicator for psychiatric symptom intensity) increase of 1.60 (95% confidence interval (CI): 0.31, 2.89), 1.71 (95% CI: 0.18, 3.23), respectively. Similarly, for each IQR increase in one and four week averages of ozone before a visit, the PSDI T-score increased by 1.66 (95% CI: 0.68, 2.65), and 1.36 (95% CI: 0.23, 2.49), respectively. Stronger associations were observed for ozone and PSDI in low house-value and low household income areas. No associations were found for PM2.5. Exposure to gaseous air pollutants was associated with a higher intensity of psychiatric symptoms among a cohort of older men, particularly in communities with lower socio-economic or housing conditions.
Low-dissipation model of three-terminal refrigerator: performance bounds and comparative analyses
Authors: Li Zhexu , Gonzalez-Ayala Julian , Yang Hanxin , Guo Juncheng , Calvo Hernández A
Published: January 2022

In the present paper, a general non-combined model of three-terminal refrigerator beyond specific heat transfer mechanisms is established based on the low-dissipation assumption. The relation between the optimized cooling power and the corresponding coefficient of performance (COP) is analytically derived, according to which the COP at maximum cooling power (CMP) can be further determined. At two dissipation asymmetry limits, upper and lower bounds of CMP are obtained and found to be in good agreement with experimental and simulated results. Additionally, comparison of the obtained bounds with previous combined model is presented. In particular it is found that the upper bounds are the same, whereas the lower bounds are quite different. This feature indicates that the claimed universal equivalence for the combined and non-combined models under endoreversible assumption is invalid within the frame of low-dissipation assumption. Then, the equivalence between various finite-time thermodynamic models needs to be reevaluated regarding multi-terminal systems. Moreover, the correlation between the combined and non-combined models is further revealed by the derivation of the equivalent condition according to which the identical upper bounds and distinct lower bounds are theoretically shown. Finally, the proposed non-combined model is proved to be the appropriate model for describing various types of thermally driven refrigerator. This work may provide some instructive information for the further establishments and performance analyses of multi-terminal low-dissipation models.
Toward accurate diagnosis and surveillance of bacterial infections using enhanced strain-level metagenomic next-generation sequencing of infected body fluids
Authors: Ruan Zhi , Zou Shengmei , Wang Zeyu , Zhang Luhan , Chen Hangfei , Wu Yuye , Jia Huiqiong , Draz Mohamed S , Feng Ye
Published: January 2022

Metagenomic next-generation sequencing (mNGS) enables comprehensive pathogen detection and has become increasingly popular in clinical diagnosis. The distinct pathogenic traits between strains require mNGS to achieve a strain-level resolution, but an equivocal concept of ‘strain’ as well as the low pathogen loads in most clinical specimens hinders such strain awareness. Here we introduce a metagenomic intra-species typing (MIST) tool (https://github.com/pandafengye/MIST), which hierarchically organizes reference genomes based on average nucleotide identity (ANI) and performs maximum likelihood estimation to infer the strain-level compositional abundance. In silico analysis using synthetic datasets showed that MIST accurately predicted the strain composition at a 99.9% average nucleotide identity (ANI) resolution with a merely 0.001× sequencing depth. When applying MIST on 359 culture-positive and 359 culture-negative real-world specimens of infected body fluids, we found the presence of multiple-strain reached considerable frequencies (30.39%–93.22%), which were otherwise underestimated by current diagnostic techniques due to their limited resolution. Several high-risk clones were identified to be prevalent across samples, including Acinetobacter baumannii sequence type (ST)208/ST195, Staphylococcus aureus ST22/ST398 and Klebsiella pneumoniae ST11/ST15, indicating potential outbreak events occurring in the clinical settings. Interestingly, contaminations caused by the engineered Escherichia coli strain K-12 and BL21 throughout the mNGS datasets were also identified by MIST instead of the statistical decontamination approach. Our study systemically characterized the infected body fluids at the strain level for the first time. Extension of mNGS testing to the strain level can greatly benefit clinical diagnosis of bacterial infections, including the identification of multi-strain infection, decontamination and infection control surveillance.
Considerations for the implementation of machine learning into acute care settings
Authors: Bishara Andrew , Maze Elijah H , Maze Mervyn
Published: January 2022

Introduction

Management of patients in the acute care setting requires accurate diagnosis and rapid initiation of validated treatments; therefore, this setting is likely to be an environment in which cognitive augmentation of the clinician’s provision of care with technology rooted in artificial intelligence, such as machine learning (ML), is likely to eventuate.

Sources of data

PubMed and Google Scholar with search terms that included ML, intensive/critical care unit, electronic health records (EHR), anesthesia information management systems and clinical decision support were the primary sources for this report.

Areas of agreement

Different categories of learning of large clinical datasets, often contained in EHRs, are used for training in ML. Supervised learning uses algorithm-based models, including support vector machines, to pair patients’ attributes with an expected outcome. Unsupervised learning uses clustering algorithms to define to which disease grouping a patient’s attributes most closely approximates. Reinforcement learning algorithms use ongoing environmental feedback to deterministically pursue likely patient outcome.

Areas of controversy

Application of ML can result in undesirable outcomes over concerns related to fairness, transparency, privacy and accountability. Whether these ML technologies irrevocably change the healthcare workforce remains unresolved.

Growing points

Well-resourced Learning Health Systems are likely to exploit ML technology to gain the fullest benefits for their patients. How these clinical advantages can be extended to patients in health systems that are neither well-endowed, nor have the necessary data gathering technologies, needs to be urgently addressed to avoid further disparities in healthcare.