bluuebunny/crossref_metadata_2025 huggingface dataset:
Holographic study of $$ T\overline{T} $$ like deformed HV QFTs: holographic entanglement entropy
Authors: Jeong Hyun-Sik , Pan Wen-Bin , Sun Ya-Wen , Wang Yuan-Tai
Published: February 2023

Abstract

We study the (d + 2)-dimensional Hyperscaling Violating (HV) geometries in the presence of both a finite temperature T and a UV cutoff rc. This gravitational system is conjectured to be dual to $$ T\overline{T} $$
T

T
¯

like deformed HV QFTs. We consider the representative quantum entanglement quantity in holography, i.e. the entanglement entropy S(A), and perform a complete analysis in all possible parameter ranges of the hyperscaling violation exponent θ and the critical dynamical exponent z to study the effect of the temperature and the cutoff. We find that the temperature has a universal effect independent of the parameters: it enhances S(A) in the small cutoff limit, while it is irrelevant in the large cutoff limit. For the cutoff effect, we find that the cutoff monotonically suppresses S(A) where its behavior depends on the parameter range. As an application of the finite temperature analysis, we study the first law of entanglement entropy, ST – ST =0 ~ ℓλ, in the small subsystem size ℓ limit. We find that λ interpolates between λ = 1 + z in the small cutoff and λ = 3 in the large cutoff, independent of the parameter range. We also provide the analytic holographic result at z = d – θ and discuss its possibility of comparison with the field theoretic result.
Bootstrapping boundaries and branes
Authors: Collier Scott , Mazáč Dalimil , Wang Yifan
Published: February 2023

Abstract

The study of conformal boundary conditions for two-dimensional conformal field theories (CFTs) has a long history, ranging from the description of impurities in one-dimensional quantum chains to the formulation of D-branes in string theory. Nevertheless, the landscape of conformal boundaries is largely unknown, including in rational CFTs, where the local operator data is completely determined. We initiate a systematic bootstrap study of conformal boundaries in 2d CFTs by investigating the bootstrap equation that arises from the open-closed consistency condition of the annulus partition function with identical boundaries. We find that this deceivingly simple bootstrap equation, when combined with unitarity, leads to surprisingly strong constraints on admissible boundary states. In particular, we derive universal bounds on the tension (boundary entropy) of stable boundary conditions, which provide a rigorous diagnostic for potential D-brane decays. We also find unique solutions to the bootstrap problem of stable branes in a number of rational CFTs. Along the way, we observe a curious connection between the annulus bootstrap and the sphere packing problem, which is a natural extension of previous work on the modular bootstrap. We also derive bounds on the boundary entropy at large central charge. These potentially have implications for end-of-the-world branes in pure gravity on AdS3.
Parity violation in the scalar trispectrum: no-go theorems and yes-go examples
Authors: Cabass Giovanni , Jazayeri Sadra , Pajer Enrico , Stefanyszyn David
Published: February 2023

Abstract

We derive a set of no-go theorems and yes-go examples for the parity-odd primordial trispectrum of curvature perturbations. We work at tree-level in the decoupling limit of the Effective Field Theory of Inflation and assume scale invariance and a Bunch-Davies vacuum. We show that the parity-odd scalar trispectrum vanishes in the presence of any number of scalar fields with arbitrary mass and any parity-odd scalar correlator vanishes in the presence of any number of spinning fields with massless de Sitter mode functions, in agreement with the findings of Liu, Tong, Wang and Xianyu [1]. The same is true for correlators with an odd number of conformally-coupled external fields. We derive these results using both the (boostless) cosmological bootstrap, in particular the Cosmological Optical Theorem, and explicit perturbative calculations. We then discuss a series of yes-go examples by relaxing the above assumptions one at the time. In particular, we provide explicit results for the parity-odd trispectrum for (i) violations of scale invariance in single-clock inflation, (ii) the modified dispersion relation of the ghost condensate (non-Bunch-Davies vacuum), and (iii) interactions with massive spinning fields. Our results establish the parity-odd trispectrum as an exceptionally sensitive probe of new physics beyond vanilla inflation.
A type of unifying relation in (A)dS spacetime
Authors: Tao Yi-Xiao , Chen Qi
Published: February 2023

Abstract

Unifying relations of amplitudes are elegant results in flat spacetime, but the research on these in (A)dS case is not very rich. In this paper, we discuss a type of unifying relation in (A)dS by using Berends-Giele currents. By taking the flat limit, we also get a semi-on-shell way to prove the unifying relations in the flat case. We also discuss the applications of our results in cosmology.
Evanescent operators in one-loop matching computations
Authors: Fuentes-Martín Javier , König Matthias , Pagès Julie , Thomsen Anders Eller , Wilsch Felix
Published: February 2023

Abstract

Effective Field Theory calculations used in countless phenomenological analyses employ dimensional regularization, and at intermediate stages of computations, the operator bases extend beyond the four-dimensional ones. The extra pieces — the evanescent operators — can ultimately be removed with a suitable renormalization scheme, resulting in a finite shift of the physical operators. Modern Effective Field Theory matching techniques relying on the method of expansion by regions have to be extended to account for this. After illustrating the importance of these shifts in two specific examples, we compute the finite shifts required to remove all evanescent operators appearing in the one-loop matching of generic ultraviolet theories to the Standard Model Effective Field Theory and elucidate the formalism for generic Effective Field Theory calculations.
Charge asymmetry in the spectra of bremsstrahlung and pair production
Authors: Krachkov Petr A. , Lee Roman N.
Published: February 2023

Abstract

We calculate the first Coulomb correction to the spectra of two processes: the electron bremsstrahlung and electron-positron photoproduction in the Coulomb field. We show that, in contrast to the results obtained in the Born approximation and in the high-energy limit, the obtained corrections for these two process are not related by the crossing symmetry substitutions. The found corrections determine the leading contribution to the charge asymmetry in these processes. We use modern multiloop methods based on the IBP reduction and on the differential equations for master integrals. The results are presented in terms of classical polylogarithms. We provide both the threshold and the high-energy asymptotics of the obtained expressions and compare them with available results.
A solvable model of flat space holography
Authors: Rosso Felipe
Published: February 2023

Abstract

We propose an explicit realization of flat space holography in two dimensions where both sides of the duality are independently defined and the boundary theory is completely solvable. In the bulk, we define a novel 𝒩 = 1 flat space supergravity theory and exactly compute the full topological expansion of its Euclidean partition function with an arbitrary number of boundaries. On the boundary, we consider a double scaled Hermitian random matrix model with Gaussian potential and use the loop equations to show it independently reproduces the bulk partition function to all orders in the topological expansion. The non-perturbative completion of the supergravity theory provided by the solvable Gaussian matrix model allows for the exact, and in many cases analytic, computation of observables in flat space quantum gravity.
Spinor-helicity formalism for massive and massless amplitudes in five dimensions
Authors: Chiodaroli Marco , Günaydin Murat , Johansson Henrik , Roiban Radu
Published: February 2023

Abstract

Five-dimensional gauge and gravity theories are known to exhibit striking properties. D = 5 is the lowest dimension where massive tensor states appear naturally, providing a testing ground for perturbative insights into six-dimensional tensor theories. Five-dimensional supergravities are highly constrained and admit elegant geometric and algebraic formulations, with global symmetries manifest at the Lagrangian level.

In this paper, we take a step towards the systematic investigation of amplitudes in five dimensions, and present a five-dimensional version of the spinor-helicity formalism, applicable to massless, massive and supersymmetric states. We give explicit representations for on-shell spinor and polarization variables such that the little-group symmetry and gauge redundancy are manifest. Massive self-dual tensor states are discussed in some detail, as well as all the on-shell supermultiplets that can appear in matter-coupled gauge and supergravity theories. As a byproduct of considering supersymmetry in the presence of central charge, we obtain massless ten-dimensional Majorana-Weyl spinors as products of five-dimensional massive spinors.

We present compact expressions for superamplitudes at multiplicity three and four, including several novel superamplitudes that either do not straightforwardly uplift to six dimensions, or have not appeared in the six-dimensional literature. We discuss several examples of five-dimensional double-copy constructions in the context of gravitational theories with massive vectors and tensors, illustrating that the formalism we construct can also be used to considerably streamline the double-copy construction of $$ \mathcal{N} $$
N
= 2 Maxwell-Einstein supergravities.
Two-loop QCD corrections to the V → $$ q\overline{q}g $$ helicity amplitudes with axial-vector couplings
Authors: Gehrmann Thomas , Peraro Tiziano , Tancredi Lorenzo
Published: February 2023

Abstract

We compute the two-loop corrections to the helicity amplitudes for the coupling of a massive vector boson to a massless quark-antiquark pair and a gluon, accounting for vector and axial-vector couplings of the vector boson and distinguishing isospin non-singlet and singlet contributions. A new four-dimensional basis for the decomposition of the amplitudes into 12 invariant tensor structures is introduced. The associated form factors are then computed up to two loops in QCD using dimensional regularization. After performing renormalization and infrared subtraction, the finite parts of the renormalized non-singlet vector and axial-vector form factors are shown agree with each other, and to reproduce the previously known two-loop amplitudes. The singlet axial-vector amplitude receives a contribution from the axial anomaly from two loops onwards. This amplitude is computed for massless and massive internal quarks. Our results provide the last missing two-loop amplitudes entering the NNLO QCD corrections of vector-boson-plus-jet production at hadron colliders.
Identifying the lead angle limit to achieve required surface roughness in ball-end milling
Authors: Pesice Matej , Vavruska Petr , Falta Jiri , Zeman Pavel , Maly Jan
Published: February 2023

When milling generally shaped surfaces with a ball-end milling tool, machined surface roughness and accuracy as well as machining productivity are often monitored. Improving one of these parameters often causes a decrease in the other monitored parameters. Therefore, knowing possible ways of influencing these parameters is important for achieving the optimum result, if possible, in all requirements. A deep understanding of how some technological parameters influence finished surface roughness is still lacking, as well as detailed knowledge of the relationships among some roughness parameters. In response, an experiment entailing machining of planar samples at different orientation angles was carried out to identify the influence of the studied parameters on the transverse roughness of the final surface. A finding was made that the resulting surface roughness is dependent on the cutting edge geometry of the particular ball-end milling tools used, and the achieving of the required surface roughness can be guaranteed by setting the specific lead angles. Furthermore, it was verified that a minimum lead angle limit can be found based on the geometric properties of the specific milling tool, and the relationship between the evaluated roughness parametersRaandRzwas found as well.
Did the Massachusetts Health Reform Program increase self-employment?
Authors: Chattopadhyay Debdeep
Published: February 2023

By providing affordable health insurance untied from employer provision, the Massachusetts Health Reform Program could increase self-employment. Previous studies have estimated both positive and negative effects of the reform on aggregate self-employment using difference-in-differences designs. In this study, I use the synthetic control methodology to confirm the absence of a statistically significant effect of the reform on aggregate self-employment. However, I do detect positive and significant short-run effects of the reform on the probability that individuals become incorporated self-employed. This effect is restricted to individuals 40 years old or younger. I also find that for employees in this age range the reform caused a significant wage reduction. This finding highlights that the higher reform-mandated health insurance coverage was at least in part financed by employees.
On the basins of attraction of a one-dimensional family of root finding algorithms: from Newton to Traub
Authors: Canela Jordi , Evdoridou Vasiliki , Garijo Antonio , Jarque Xavier
Published: February 2023

In this paper we study the dynamics of damped Traub’s methods$$T_\delta $$Tδwhen applied to polynomials. The family of damped Traub’s methods consists of root finding algorithms which contain both Newton’s ($$\delta =0$$δ=0) and Traub’s method ($$\delta =1$$δ=1). Our goal is to obtain several topological properties of the basins of attraction of the roots of a polynomialpunder$$T_1$$T1, which are used to determine a (universal) set of initial conditions for which convergence to all roots ofpcan be guaranteed. We also numerically explore the global properties of the dynamical plane for$$T_\delta $$Tδto better understand the connection between Newton’s method and Traub’s method.
Rate of convergence and stability analysis of a modified fixed pivot technique for a fragmentation equation
Authors: Saha Jitraj , Singh Mehakpreet
Published: February 2023

This study presents the convergence and stability analysis of a recently developed fixed pivot technique for fragmentation equations (Liao et al. in Int J Numer Methods Fluids 87(4):202–215, 2018). The approach is based on preserving two integral moments of the distribution, namely (a) the zeroth-order moment, which defines the number of particles, and (b) the first-order moment, which describes the total mass in the system. The present methodology differs mathematically in a way that it delivers the total breakage rate between a mother and a daughter particle immediately, whereas existing numerical techniques provide the partial breakup rate of a mother and daughter particle. This affects the computational efficiency and makes the current model reliable for CFD simulations. The consistency and unconditional second-order convergence of the method are proved. This demonstrates efficiency of the method over the fixed pivot technique (Kumar and Warnecke in Numer Math 110(4):539–559, 2008) and the cell average technique (Kumar and Warnecke in Numer Math 111(1):81–108, 2008). Numerical results are compared against the cell average technique and the experimental order of convergence is calculated to confirm the theoretical order of convergence.
Machine learning predictive performance evaluation of conventional and fuzzy radiomics in clinical cancer imaging cohorts
Authors: Grahovac M. , Spielvogel C. P. , Krajnc D. , Ecsedi B. , Traub-Weidinger T. , Rasul S. , Kluge K. , Zhao M. , Li X. , Hacker M. , Haug A. , Papp Laszlo
Published: February 2023

Background

Hybrid imaging became an instrumental part of medical imaging, particularly cancer imaging processes in clinical routine. To date, several radiomic and machine learning studies investigated the feasibility of in vivo tumor characterization with variable outcomes. This study aims to investigate the effect of recently proposed fuzzy radiomics and compare its predictive performance to conventional radiomics in cancer imaging cohorts. In addition, lesion vs. lesion+surrounding fuzzy and conventional radiomic analysis was conducted.

Methods

Previously published 11C Methionine (MET) positron emission tomography (PET) glioma, 18F-FDG PET/computed tomography (CT) lung, and 68GA-PSMA-11 PET/magneto-resonance imaging (MRI) prostate cancer retrospective cohorts were included in the analysis to predict their respective clinical endpoints. Four delineation methods including manually defined reference binary (Ref-B), its smoothed, fuzzified version (Ref-F), as well as extended binary (Ext-B) and its fuzzified version (Ext-F) were incorporated to extract imaging biomarker standardization initiative (IBSI)-conform radiomic features from each cohort. Machine learning for the four delineation approaches was performed utilizing a Monte Carlo cross-validation scheme to estimate the predictive performance of the four delineation methods.

Results

Reference fuzzy (Ref-F) delineation outperformed its binary delineation (Ref-B) counterpart in all cohorts within a volume range of 938–354987 mm3 with relative cross-validation area under the receiver operator characteristics curve (AUC) of  +4.7–10.4. Compared to Ref-B, the highest AUC performance difference was observed by the Ref-F delineation in the glioma cohort (Ref-F: 0.74 vs. Ref-B: 0.70) and in the prostate cohort by Ref-F and Ext-F (Ref-F: 0.84, Ext-F: 0.86 vs. Ref-B: 0.80). In addition, fuzzy radiomics decreased feature redundancy by approx. 20%.

Conclusions

Fuzzy radiomics has the potential to increase predictive performance particularly in small lesion sizes compared to conventional binary radiomics in PET. We hypothesize that this effect is due to the ability of fuzzy radiomics to model partial volume effects and delineation uncertainties at small lesion boundaries. In addition, we consider that the lower redundancy of fuzzy radiomic features supports the identification of imaging biomarkers in future studies. Future studies shall consider systematically analyzing lesions and their surroundings with fuzzy and binary radiomics.
Laser ablation research and development: 60 years strong
Authors: Russo Richard E.
Published: February 2023

Slightly more than 60 years have passed since the introduction of the laser. The unique property of high peak power in short pulses has led to applications in which light energy replaces mechanical energy for removing mass, structuring surfaces, creating new materials, weapons, remote analysis, fusion, surgery, and many other esoteric applications that fall under the process called laser ablation. This manuscript addresses several accomplishments in laser ablation research and development, including fundamental behavior, some unique applications with emphasis on chemical analysis, and a current interest to measure isotope ratios in laser induced plasmas at atmospheric pressure.
Symmetric three-port laparoscopic Roux-en-Y gastric bypass: a novel technique that is safe, effective, and feasible
Authors: Zhou Biao , Cao Xinyu , Wang Zhe , Zhang Nianrong , Liu Baoyin , Meng Hua
Published: February 2023

Purpose

Single-incision laparoscopic surgery (SILS) has been validated as a safe approach for bariatric surgery. However, as the utilization of SILS in bariatric surgery is still limited by its disadvantages, this study analyzes the outcomes of symmetric three-port laparoscopic Roux-en-Y gastric bypass (STLGB).

Methods

The medical records of patients who underwent STLGB between January 2018 and February 2021 were analyzed retrospectively using an institutional database. The patients were divided into four groups according to their baseline body mass index (BMI). The primary endpoints were operative time, length of stay, complication rate, and weight loss 12 months after surgery.

Results

We analyzed the records of 101 patients who underwent STLGB. There was a slight predominance of women (n = 61; 60.4%). The mean operative time was 97.16 ± 38.79 min and the length of stay in the hospital after surgery was 2.79 ± 1.4 days. One patient (0.99%) suffered a gastrojejunal anastomosis leak within 30 days of surgery. There were no significant differences in LOS, complication rate, or cosmetic score among the four groups. The mean BMI reduction was 8.67 kg/m2 and the % total weight loss (%TWL) was 24.37%. Weight loss measured 12 months after surgery was significantly different among the four groups.

Conclusions

STLGB is safe, effective, and feasible for all kinds of patients. It is reproducible with standardization of the procedure.
Comparison of obturation quality in natural and replica teeth root-filled using different sealers and techniques
Authors: Kooanantkul Chuta , Shelton Richard M , Camilleri Josette
Published: February 2023

Objectives

This study aims to assess the obturation efficacy of sealers placed with different techniques using microcomputed tomography (µCT) and assess the influence of µCT testing parameters on the obturation data obtained.

Materials and methods

Incisors and mesial roots of lower molars with standardized root length were scanned using µCT, and one tooth of each type was 3D printed in acrylic. Two obturation techniques (warm vertical and single cone) and 4 sealer types (AH Plus, BioRoot RCS, Totalfill BC, and Bio-C Sealers) were assessed following storage in Hank’s balanced salt solution for 3 and 6 months by assessing gap and void volume percentages on both natural and replica incisor and molar roots. The storage solution was analysed to assess calcium ion leaching. The influence of temperature, tooth positioning, and moisture content of the teeth while µCT scanning was also investigated.

Results

The obturation quality in the incisor group was the same using both natural teeth and replicas (p > 0.05). No changes in void volume were identified when comparing the same sealer using different obturation techniques. The premixed sealers used in single-cone obturation exhibited high void volume in the 3D printed replicas in the long term. The temperature, positioning, and moisture content of the teeth did not affect the outcome of µCT testing.

Conclusions

BioRoot RCS, Totalfill BC, and Bio-C Sealers are suitable for obturation of both complex and simple root canal systems using different obturation techniques with BioRoot RCS exhibiting the highest calcium ion release. 3D printed acrylic teeth can be used to assess the obturation quality in uncomplicated root canal systems. µCT parameters had no significant effect on the µCT measurement.

Clinical relevance

The single-cone obturation technique with hydraulic sealer is a simple technique that can be used for obturation of all root canal systems.
Emotion processing in maltreated boys and girls: Evidence for latent vulnerability
Authors: Diaconu Bianca , Kohls Gregor , Rogers Jack C. , Pauli Ruth , Cornwell Harriet , Bernhard Anka , Martinelli Anne , Ackermann Katharina , Fann Nikola , Fernandez-Rivas Aranzazu , Gonzalez-Torres Miguel Angel , Gonzalez de Artaza-Lavesa Maider , Hervas Amaia , Stadler Christina , Konrad Kerstin , Freitag Christine M. , Fairchild Graeme , Rotshtein Pia , De Brito Stephane A.
Published: February 2023

Evidence of alterations in emotion processing in maltreated youth has been hypothesized to reflect latent vulnerability for psychopathology. However, previous studies have not systematically examined the influence of psychopathology on the results. Here, we examined emotion recognition and learning in youth who differed in terms of presence vs. absence of maltreatment and psychopathology and tested for potential sex effects. Maltreatment and psychopathology were assessed in 828 youth (514 females) aged 9–18 years using diagnostic interviews and self- and parent-report questionnaires. Emotion recognition was assessed via identification of morphed facial expressions of six universal emotions. For emotion learning, reward and punishment values were assigned to novel stimuli and participants had to learn to correctly respond/withhold response to stimuli to maximize points. A three-way interaction of maltreatment by psychopathology by emotion indicated that when psychopathology was low, maltreated youth were less accurate than non-maltreated youth for happy, fear and disgust. A three-way interaction of sex, maltreatment and emotion indicated that maltreated girls and boys were impaired for fear, but girls showed an impairment for happy, while boys for disgust. There were no effects of maltreatment, psychopathology, or sex on reward learning. However, a two-way interaction between sex and maltreatment showed that maltreated girls were worse at learning from punishment relative to non-maltreated girls, while maltreated boys were better than non-maltreated boys. The study provides the first clear evidence of latent-vulnerability in emotion recognition in maltreated youth and suggests that girls and boys might be characterized by distinct profiles of emotion recognition and learning following maltreatment.
Autoimmunity and hernia mesh: fact or fiction?
Authors: Jisova B. , Wolesky J. , Strizova Z. , de Beaux A. , East B.
Published: February 2023

Background

There is an increasing number of patients following hernia surgery with implanted mesh reporting symptoms that could indicate autoimmune or allergic reactions to mesh. ‘Allergy’ to metals, various drugs, and chemicals is well recognised. However, hypersensitivity, allergy or autoimmunity caused by surgical mesh has not been proven by a scientific method to date. The aim of this study was twofold: to describe the pathophysiology of autoimmunity and foreign body reaction and to undertake a systematic review of surgical mesh implanted at the time of hernia repair and the subsequent development of autoimmune disease.

Methods

A systematic review using the PRISMA guidelines was undertaken. Pubmed (Medline), Google Scholar and Cochrane databases were searched for all English-written peer-reviewed articles published between 2000 and 2021. The search was performed using the keywords “hernia”, “mesh”, “autoimmunity”, “ASIA”, “immune response”, “autoimmune response”.

Results

Seven papers were included in the final analysis—three systematic reviews, three cohort studies and one case report. Much of the current data regarding the association of hernia mesh and autoimmunity relies on retrospective cohort studies and/or case reports with limited availability of cofounding factor data linked to autoimmune disease such as smoking status or indeed a detailed medical history of patients. Three systematic reviews have discussed this topic, each with a slightly different approach and none of them has identified causality between the use of mesh and the subsequent development of autoimmune disease.

Conclusion

There is little evidence that the use of polypropylene mesh can lead to autoimmunity. A large number of potential triggers of autoimmunity along with the genetic predisposition to autoimmune disease and the commonality of hernia, make a cause and effect difficult to unravel at present. Biomaterials cause foreign body reactions, but a chronic foreign body reaction does not indicate autoimmunity, a common misunderstanding in the literature.
New technologies for the classification of proximal humeral fractures: Comparison between Virtual Reality and 3D printed models—a randomised controlled trial
Authors: Almirón Santa-Bárbara Rafael , García Rivera Francisco , Lamb Maurice , Víquez Da-Silva Rodrigo , Gutiérrez Bedmar Mario
Published: February 2023

Correct classification of fractures according to their patterns is critical for developing a treatment plan in orthopaedic surgery. Unfortunately, for proximal humeral fractures (PHF), methods for proper classification have remained a jigsaw puzzle that has not yet been fully solved despite numerous proposed classifications and diagnostic methods. Recently, many studies have suggested that three-dimensional printed models (3DPM) can improve the interobserver agreement on PHF classifications. Moreover, Virtual Reality (VR) has not been properly studied for classification of shoulder injuries. The current study investigates the PHF classification accuracy relative to an expert committee when using either 3DPM or equivalent models displayed in VR among 36 orthopaedic surgery residents from different hospitals. We designed a multicentric randomised controlled trial in which we created two groups: a group exposed to a total of 34 3DPM and another exposed to VR equivalents. Association between classification accuracy and group assignment (VR/3DPM) was assessed using mixed effects logistic regression models. The results showed VR can be considered a non-inferior technology for classifying PHF when compared to 3DPM. Moreover, VR may be preferable when considering possible time and resource savings along with potential uses of VR for presurgical planning in orthopaedics.
Study on Quality Control of Tenofovir Disoproxil Fumarate Enantiomers by High-Performance Liquid Chromatography–Mass Spectrometry
Authors: Lin Li , Huang Lingyi , Ke Yanbing , Xu Xiaowen , Huang Liying
Published: February 2023

This study aims at developing a high-performance liquid chromatography–mass spectrometry (LC–MS) method to analyze tenofovir disoproxil fumarate (TDF) and its pharmaceutical preparations. Several cyclodextrin mobile-phase additives were applied to reversed-phase and normal-phase chromatography, and the effects of three chiral stationary phases on the TDF separation were investigated in this study. The R-type and S-type of TDF tablets were quantitatively analyzed in the single ion monitoring (SIM) scanning mode with a Unichiral CMD column. This method has been successfully applied to the separation and quantification of TDF and its isomers. The linear ranges of (R)-TDF and (S)-enantiomer were 1–20 and 0.2–16 μg/mL, respectively. The limit of detection for (R)-TDF and (S)-enantiomer was 0.0015 and 0.0012 μg/mL, respectively. (S)-enantiomer was not detected in the formulas from all the seven manufacturers, and the drug content of each took more than 98.5% of the labeled amount, which complies with the regulations. The method shows its advantages on high sensitivity, low detection limit, good practicability, and repeatability. The proposed method may provide a novel platform for separation of TDF enantiomers and quality control of TDF raw materials and preparations.
The numerical solution of fractional integral equations via orthogonal polynomials in fractional powers
Authors: Pu Tianyi , Fasondini Marco
Published: February 2023

We present a spectral method for one-sided linear fractional integral equations on a closed interval that achieves exponentially fast convergence for a variety of equations, including ones with irrational order, multiple fractional orders, non-trivial variable coefficients, and initial-boundary conditions. The method uses an orthogonal basis that we refer to as Jacobi fractional polynomials, which are obtained from an appropriate change of variable in weighted classical Jacobi polynomials. New algorithms for building the matrices used to represent fractional integration operators are presented and compared. Even though these algorithms are unstable and require the use of high-precision computations, the spectral method nonetheless yields well-conditioned linear systems and is therefore stable and efficient. For time-fractional heat and wave equations, we show that our method (which is not sparse but uses an orthogonal basis) outperforms a sparse spectral method (which uses a basis that is not orthogonal) due to its superior stability.
Understanding COVID-19 Vaccine Confidence in People Living with HIV: A pan-Canadian Survey
Authors: Costiniuk Cecilia T. , Singer Joel , Needham Judy , Yang Yanbo , Qian Hong , Chambers Catharine , Burchell Ann N. , Samji Hasina , Colmegna Ines , del Canto Sugandhi , Godin Guy-Henri , Habanyama Muluba , Hui Christian , Kroch Abigail , Mandarino Enrico , Margolese Shari , Martin Carrie , Owino Maureen , Mohammadi Tima , Zhang Wei , Pelaez Sandra , Kovacs Colin , Benko Erika , Vulesevic Branka , Cooper Curtis L. , Anis Aslam H.
Published: February 2023

Understanding the roots of Covid-19 vaccine hesitancy in at-risk groups, such as persons living with HIV (PLWH), is of utmost importance. We developed a modified Vaccine Hesitancy Scale (VHS) questionnaire using items from the National Advisory Committee on Immunization Acceptability Matrix. To examine factors associated with receiving COVID-19 vaccine and the link between vaccine attitudes and beliefs with vaccine behavior, PLWH were recruited via social media and community-based organizations (February-May 2022). Descriptive statistics were used to summarize results. Total VHS score was generated by adding Likert scale scores and linear regression models used to compare results between participants who received or did not receive COVID-19 vaccines. Logistic regression models were used to identify factors associated with vaccine uptake. A total of 246 PLWH indicated whether they received a COVID-19 vaccine. 89% received ≥ 1 dose. Mean total VHS(SD) for persons having received ≥ 1 COVID-19 vaccine was 17.8(6.2) vs. 35.4(9.4) for participants not having received any COVID-19 vaccine. Persons who received ≥ 1 dose were significantly older than those who had not received any (48.4 ± 13.8 vs. 34.0 ± 7.7 years, p < 0.0001). The majority of participants considered COVID-19 vaccination important for their health(81.3%) and the health of others(84.4%). Multivariate logistic regression revealed the odds of taking ≥ 1dose were increased 2.4-fold [95% CI 1.6, 3.5] with each increase in age of 10 years (p < 0.0001). Sex and ethnicity were not different between groups. In conclusion, PLWH accept COVID-19 vaccines for both altruistic and individual reasons. With evolving recommendations and increasing numbers of booster vaccines, we must re-examine the needs of PLWH regularly.
Pre-exposure Prophylaxis Persistence at a Diverse Sexual Health Clinic: Comparison of the pre-COVID-19 era to the COVID-19 era
Authors: Platt Laura , Shebl Fatma M. , Qian Yiqi , Spanos Nicholas , Nolan Cody P. , Ard Kevin L. , Bassett Ingrid V.
Published: February 2023

The COVID-19 pandemic interrupted health care delivery and exacerbated disparities. Many sexual health clinics transitioned to telemedicine, including for pre-exposure prophylaxis (PrEP). We conducted a retrospective cohort study of patients at an urban sexual health clinic to assess the likelihood and predictors of PrEP persistence in the year following PrEP initiation. We compared patients starting PrEP in the four months preceding the first COVID surge to those starting PrEP one year prior. We found lower PrEP persistence in the COVID cohort compared to the pre-COVID cohort (50.8% vs. 68.9%, respectively). In both cohorts, most care was provided through in-person visits and telemedicine was rare. In the pre-COVID cohort, older patients and those identifying as non-Hispanic White were more likely to persist on PrEP. In the COVID cohort, these disparities in PrEP persistence were not observed. Flexible models of care may facilitate equitable care engagement and re-engagement.
Carbon emissions and sustainability in Covid-19’s waves: evidence from a two-state dynamic Markov-switching regression (MSR) model
Authors: Konstantakis Konstantinos N. , Michaelides Panayotis G. , Xidonas Panos , Yfanti Stavroula
Published: February 2023

Throughout the world, carbon emissions have decreased in an unprecedented way as a result of the Covid-19 pandemic. The purpose of this paper is to investigate whether a rebound effect in carbon emissions is anticipated following the extraction of information related to the beliefs of investors. A suitable Markov switching model is used in this paper to adapt the safe haven financial methodology to an environmental sustainability perspective. Analytically, the aforementioned situation is modeled by estimating a two-state dynamic Markov-Switching Regression (MSR), with a state-dependent intercept term to capture the dynamics of the series, across unobserved regimes. In light of the results of the research and the robustness checks, investors are anticipating a rebound effect on the total quantity of carbon emissions.
Improving the predictive accuracy of the cross-selling of consumer loans using deep learning networks
Authors: Boustani Noureddine , Emrouznejad Ali , Gholami Roya , Despic Ozren , Ioannou Athina
Published: February 2023

Traditionally most cross-selling models in retail banking use demographics information and interactions with marketing as input to statistical models or machine learning algorithms to predict whether a customer is willing to purchase a given financial product or not. We overcome with such limitation by building several models that also use several years of account transaction data. The objective of this study is to analysis credit card transactions of customers, in order to come up with a good prediction in cross-selling products. We use deep-learning algorithm to analyze almost 800,000 credit cards transactions. The results show that such unique data contains valuable information on the customers’ consumption behavior and it can significantly increase the predictive accuracy of a cross-selling model. In summary, we develop an auto-encoder to extract features from the transaction data and use them as input to a classifier. We demonstrate that such features also have predictive power that enhances the performance of the cross-selling model even further.
SARS-COV-2 spike protein promotes RPE cell senescence via the ROS/P53/P21 pathway
Authors: Zhang Yuhang , Peng Xuyan , Xue Mengjiao , Liu Jingjing , Shang Guohui , Jiang Mingjun , Chen Dandan , Liu Baixue , Wang Yuxuan , Jia Xiaolin , Xu Jianqing , Zhang Fengyan , Hu Yanzhong
Published: February 2023

SARS-Cov-2 infection, which has caused the COVID-19 global pandemic, triggers cellular senescence. In this study, we investigate the role of the SARS-COV-2 spike protein (S-protein) in regulating the senescence of RPE cells. The results showed that administration or overexpression of S-protein in ARPE-19 decreased cell proliferation with cell cycle arrest at the G1 phase. S-protein increased SA-β-Gal positive ARPE-19 cells with high expression of P53 and P21, senescence-associated inflammatory factors (e.g., IL-1β, IL-6, IL-8, ICAM, and VEGF), and ROS. Elimination of ROS by N-acetyl cysteine (NAC) or knocking down p21 by siRNA diminished S-protein-induced ARPE cell senescence. Both administrated and overexpressed S-protein colocalize with the ER and upregulate ER-stress-associated BIP, CHOP, ATF3, and ATF6 expression. S-protein induced P65 protein nuclear translocation. Inhibition of NF-κB by bay-11-7082 reduced S-protein-mediated expression of senescence-associated factors. Moreover, the intravitreal injection of S-protein upregulates senescence-associated inflammatory factors in the zebrafish retina. In conclusions, the S-protein of SARS-Cov-2 induces cellular senescence of ARPE-19 cells in vitro and the expression of senescence-associated cytokines in zebrafish retina in vivo likely by activating ER stress, ROS, and NF-κb. These results may uncover a potential association between SARS-cov-2 infection and development of AMD.
International agreement for the use and exchange of classical biological control genetic resources: a practical proposal
Authors: Mason Peter G. , Mc Kay Fernando , Silvestri Luciana C. , Hill Martin , Weyl Philip , Hinz Hariet L. , Brodeur Jacques , Vitorino Marcelo Diniz , Barratt Barbara I. P.
Published: February 2023

The Nagoya Protocol on Access and Benefit Sharing (ABS) was implemented to further develop the third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the utilization of genetic resources. Interpretation of this agreement is wide-ranging and there is concern that if ABS measures are poorly implemented biological control and the resultant public good will be greatly impeded. The ethos of multilateral use and exchange of genetic resources used in classical biological control will be particularly affected. In the spirit of the fair and equitable sharing of benefits arising out of the utilization of genetic resources, we propose a simple practical solution in the form of an international agreement on the use and exchange of classical biological control genetic resources.
Characterising uncertainty in risk assessments for biological control: using case studies from New Zealand to inform future research
Authors: Barratt B. I. P. , Meenken E. D. , Withers T. M.
Published: February 2023

Areas of uncertainty in the assessment of risks and benefits in applications for new biological control agents submitted to the regulator for proposed introduction into New Zealand were identified. This was done with the aim of informing future research priorities which might be able to address and reduce these areas of uncertainty to assist decision-making in the future. A sample of 20 applications received by the Environmental Protection Authority (EPA) between 2009 and 2019 were selected, with examples from weed and insect targets. Expressions of uncertainty were identified by applicants as well as the EPA staff assessment report of the application, and the final decision document prepared by the Authority’s committee. The most common risk uncertainties expressed were potential direct non-target effects (85%), cultural risks (75%), and whether there were existing (and possibly effective) natural enemies of the target already present in the new range (70%). Food web indirect effects and adequacy of host range testing were also mentioned in more than half of the case study applications and associated documents. For uncertainty relating to benefits, 75% of case studies mentioned uncertainty about the efficacy of the proposed biological control agent, or if the agent would be successful by establishing and spreading (60%). For several of the case studies questions were raised about the method of cost: benefit analyses that had been presented in the application. Recommendations for future research are presented.
On a large-stepsize integrator for charged-particle dynamics
Authors: Lubich Christian , Shi Yanyan
Published: February 2023

Xiao and Qin (Comput Phys Commun 265:107981, 2021) recently proposed a remarkably simple modification of the Boris algorithm to compute the guiding centre of the highly oscillatory motion of a charged particle with step sizes that are much larger than the period of gyrorotations. They gave strong numerical evidence but no error analysis. This paper provides an analysis of the large-stepsize modified Boris method in a setting that has a strong non-uniform magnetic field and moderately bounded velocities, considered over a fixed finite time interval. The error analysis is based on comparing the modulated Fourier expansions of the exact and numerical solutions, for which the differential equations of the dominant terms are derived explicitly. Numerical experiments illustrate and complement the theoretical results.
Low-rank Parareal: a low-rank parallel-in-time integrator
Authors: Carrel Benjamin , Gander Martin J. , Vandereycken Bart
Published: February 2023

In this work, the Parareal algorithm is applied to evolution problems that admit good low-rank approximations and for which the dynamical low-rank approximation (DLRA) can be used as time stepper. Many discrete integrators for DLRA have recently been proposed, based on splitting the projected vector field or by applying projected Runge–Kutta methods. The cost and accuracy of these methods are mostly governed by the rank chosen for the approximation. These properties are used in a new method, called low-rank Parareal, in order to obtain a time-parallel DLRA solver for evolution problems. The algorithm is analyzed on affine linear problems and the results are illustrated numerically.
The Association Between Prenatal Maternal
Stress and Adolescent Affective Outcomes is Mediated by Childhood Maltreatment and
Adolescent Behavioral Inhibition System Sensitivity
Authors: Sebők-Welker T. , Posta E. , Ágrez K. , Rádosi A. , Zubovics E. A. , Réthelyi M. J. , Ulbert I. , Pászthy B. , Bunford N.
Published: February 2023

Prenatal maternal stress is linked to offspring outcomes; however, there is
little research on adolescents, behavioral, transdiagnostic outcomes, or the mechanisms
through which relations operate. We examined, in N = 268 adolescents (Mage = 15.31 years; SD = 1.063; 57.8% boys)
whether prenatal maternal stress is associated with adolescent affective outcomes;
whether this association is mediated, serially, by childhood home atmosphere and
adolescent behavioral inhibition system (BIS) sensitivity; and whether mediational
effects are moderated by adolescent attention-deficit/hyperactivity disorder or maternal
internalizing symptomology. Prenatal maternal daily stress and major life events were
associated with adolescent outcomes through childhood negative atmosphere/neglect and
BIS sensitivity, with no evidence of moderation. Results have implications regarding the
effect of prenatal maternal stress on offspring outcomes and regarding corresponding
sensitive periods.
Is Future Mental Imagery Associated with Reduced Impact of the COVID-19 Pandemic on Negative Affect and Anhedonic Symptoms in Young People?
Authors: Hutchinson Taryn , Riddleston Laura , Pile Victoria , Meehan Alan , Shukla Meenakshi , Lau Jennifer
Published: February 2023

Background

Difficulties with prospective mental images are associated with adolescent depression. Current treatments mainly focus on verbal techniques to reduce negative affect (e.g. low mood) rather than enhancing positive affect, despite anhedonia being present in adolescents. We investigated the concurrent relationships between the vividness of negative and positive prospective mental imagery and negative affect and positive affect; and examined whether negative and positive prospective mental imagery moderated the impact of recent stress (COVID-19-linked stress) on negative and positive affect.

Methods

2602 young people (12–25 years) completed the Prospective Imagery Task and self-reported on symptoms of negative affect, anhedonia and COVID-19 linked stress.

Results

Elevated vividness of negative future mental imagery and reduced vividness of positive future mental imagery were associated with increased negative affect, whereas only reduced vividness of positive future imagery was associated with increased symptoms of anhedonia. Elevated vividness of negative future images amplified the association between COVID-19 linked stress and negative affect, while elevated vividness of positive future images attenuated the association between COVID-19 linked stress and anhedonia.

Conclusions

Future mental imagery may be differentially associated with negative and positive affect, but this needs to be replicated in clinical populations to support novel adolescent psychological treatments.