bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the impact of design criteria for reference sets on performance evaluation of signal detection algorithms: The case of drug–drug interactions
Authors: Kontsioti Elpida , Maskell Simon , Pirmohamed Munir
Published: March 2023

Purpose

To evaluate the impact of multiple design criteria for reference sets that are used to quantitatively assess the performance of pharmacovigilance signal detection algorithms (SDAs) for drug–drug interactions (DDIs).

Methods

Starting from a large and diversified reference set for two‐way DDIs, we generated custom‐made reference sets of various sizes considering multiple design criteria (e.g., adverse event background prevalence). We assessed differences observed in the performance metrics of three SDAs when applied to FDA Adverse Event Reporting System (FAERS) data.

Results

For some design criteria, the impact on the performance metrics was neglectable for the different SDAs (e.g., theoretical evidence associated with positive controls), while others (e.g., restriction to designated medical events, event background prevalence) seemed to have opposing and effects of different sizes on the Area Under the Curve (AUC) and positive predictive value (PPV) estimates.

Conclusions

The relative composition of reference sets can significantly impact the evaluation metrics, potentially altering the conclusions regarding which methodologies are perceived to perform best. We therefore need to carefully consider the selection of controls to avoid misinterpretation of signals triggered by confounding factors rather than true associations as well as adding biases to our evaluation by “favoring” some algorithms while penalizing others.
A randomized, double‐blind, single‐dose study to assess bioequivalence of MB02 biosimilar after manufacturing iteration and reference bevacizumab
Authors: Schwabe C. , Cole A. , Espigares‐Correa A. , Beydon M. E. , Florez‐Igual A. , Queiruga‐Parada J.
Published: March 2023

To investigate and compare the pharmacokinetic (PK) profiles of MB02 products, before and after optimizing the manufacturing process, and reference bevacizumab to establish bioequivalence between them. In this randomized, double‐blind, single dose, parallel study, 114 healthy male volunteers were randomized 1:1:1 to receive a 1 mg/kg intravenous dose of MB02‐SP, MB02‐DM, or US‐bevacizumab. The follow‐up period was 100 days. PK similarity between them was determined using the standard bioequivalence criteria (0.80–1.25) for the area under the serum concentration–time curve from time 0 extrapolated to infinity and the maximum observed serum concentration. Study results showed that the PK profiles of bevacizumab were similar. Statistical analysis demonstrated that for each pairwise comparison there were no differences. The 90% CIs for the ratios of geometric least squares means were fully contained within the predefined similarity acceptance limits and ranged from 0.899 to 1.12 for area under the curve and from 0.887 to 1.11 for maximum concentration. A total of 159 adverse events were reported by 76 subjects who received the study drug. The majority (90.6%) of the reported adverse events were grade 1 in severity, with 9.4% as grade 2 in severity. None were considered as grade 3, 4, or 5. Treatment‐induced anti‐drug antibodies incidence was 21.6%, 33.3%, and 23.7% for the treatment of MB02‐SP, MB02‐DM, and US‐bevacizumab, respectively. No subjects showed treatment‐induced neutralizing anti‐drug antibodies. This study demonstrates the PK, safety, and immunogenicity similarity and bioequivalence of MB02‐SP, MB02‐DM, and the reference product bevacizumab.
Simulation of Neuronal Membrane Behavior Based on Graphene Oxide Memristor
Authors: Sparvoli Marina , Marma Jonas S. , Jorge Fábio O. , Chubaci José F. D.
Published: March 2023

Computing and neuromorphic engineering areas have gained notoriety over the past few years. The current paradigm of computing, based on a centralized system, is an obstacle to evolution. It is necessary to leave Von Neumann's paradigm behind and invest in a more organic and decentralized model of technology. Neuromorphic computers are not made with transistors, but with memristors, electronic components are capable of retaining memory. In this study, the aim is to analyze the behavior of a memristor based on graphene oxide (GO) doped with silver simulating the neuronal membrane and validate the operation of the resistor–capacitor (RC) circuit as a possible tool for analysis of memristor devices. Electrical analyses are carried out in two stages: first, an I × V analysis of device parameters is carried out with a picoammeter; then, a test with a developed RC circuit is carried out in three conditions: a simulated RC circuit, an experimental analysis of the same circuit, and finally, the RC circuit is associated with the memristor. Memristor device presents threshold switching, which is a desirable feature when it is required to simulate neuronal firing. In addition, when associated with the RC circuit, the curve behavior obtained for charging and discharging the capacitor becomes nonlinear.
Double‐Absorber CZTS/Sb2Se3 Architecture for High‐Efficiency Solar‐Cell Devices
Authors: Kumar Atul , Sujith M. , Valarmathi K. , Kumar Rajnish , Al-Asbahi Bandar Ali , Ahmed Abdullah Ahmed Ali
Published: March 2023

The design and configuration of solar cells are critical for photovoltaic action and achieving high efficiency. Herein, the double‐absorber solar‐cell architecture of low‐bandgap Sb2Se3 and high‐bandgap Cu2ZnSnS4 (CZTS) absorbers for broader spectrum utilization leading to higher efficiency are comprehensively analyzed. The cost‐effective chalcogenides CZTS and Sb2Se3 for high‐efficiency dual‐absorber configuration to show the possibility of high wattage at a lower cost are taken. The crucial parameters of bandgap pair and thickness are optimized for synergetic device performance and optimal utilization of the incident spectrum. By introducing an additional absorber–absorber interface, the interfacial defect at CZTS/Sb2Se3 is lowered by optimizing the band offset for the efficient functioning of a double–absorber device. The proposed device has straightforward NiO/CZTS/Sb2Se3/AZO architecture suitable for low‐cost fabrication with high efficiency of 30.9%.
Pseudoprogression during induction treatment with nivolumab plus ipilimumab combined with chemotherapy for metastatic lung adenocarcinoma: A case report
Authors: Kunimatsu Yusuke , Kano Yukari , Tsutsumi Rei , Sato Izumi , Tanimura Mai , Tanimura Keiko , Takeda Takayuki
Published: March 2023

The incidence rate of pseudoprogression during immune checkpoint inhibitor monotherapy for non‐small cell lung cancer is reportedly 3.6%–6.9%, while pseudoprogression during chemoimmunotherapy is rare. Reports on pseudoprogression during dual immunotherapy combined with chemotherapy are lacking. Herein, a 55‐year‐old male with invasive mucinous adenocarcinoma (cT2aN2M1c [OTH, PUL], stage IVB, and programmed death‐ligand 1 expression <1%), renal dysfunction, and disseminated intravascular coagulation was treated with carboplatin, solvent‐based paclitaxel, nivolumab, and ipilimumab. After treatment initiation, computed tomography (CT) on day 14 showed disease progression. The patient was diagnosed with pseudoprogression because of a lack of symptoms, improved platelet count, and decreased fibrin/fibrinogen degradation product levels. CT on day 36 showed a reduction in the primary lesion size, multiple lung metastases, and mesenteric metastases. Therefore, pseudoprogression should be considered during dual immunotherapy with chemotherapy.
Climate change impacts on native cutthroat trout habitat in Colorado streams
Authors: Ma Chenchen , Morrison Ryan R. , White Daniel C. , Roberts James , Kanno Yoichiro
Published: March 2023

Headwater streams support vital aquatic habitat yet are vulnerable to changing climate due to their high elevation and small size. Coldwater fish are especially sensitive to the altered streamflow and water temperature regimes during summer low flow periods. Though previous studies have provided insights on how changes in climate and alterations in stream discharge may affect habitat availability for various native cutthroat trout species, suitable physical habitats have not been evaluated under future climate projections for the threatened Greenback Cutthroat Trout (GBCT) native to headwater regions of Colorado, USA. Thus, this study used field data collected from selected headwater streams across the current distribution of GBCT to construct one‐dimensional hydraulic models to evaluate streamflow and physical habitat under four future climate projections. Results illustrate reductions in both predicted streamflow and physical habitat for all future climate projections across study sites. The projected mean summer streamflow shows greater decline (−52% on average) compared to the projected decline in mean August flow (−21% on average). Moreover, sites located at a relative higher elevation with larger substrate and steeper slope were projected to experience more reductions in physical habitat due to streamflow reductions. Specifically, streams with step‐pool morphologies may experience grater changes in available habitat compared to pool‐riffle streams. Future climate change studies related to coldwater fish that examine spatial variation in flow alteration could provide novel data to complement the existing literature on the thermal characteristics. Tailoring reintroduction and management efforts for GBCT to the individual headwater stream with adequate on‐site monitoring could provide a more holistic conservation approach.
On the security of ring learning with error‐based key exchange protocol against signal leakage attack
Authors: Pursharthi Komal , Mishra Dheerendra
Published: March 2023

Due to the rapid development of mobile communication and hardware technologies, several mobile‐based web applications have gained popularity among mobile users. Mobile users can utilize these devices to access numerous services over the Internet. To ensure secure communication, different key exchange and authentication (KEA) protocols are proposed and frequently used. However, due to the advent of quantum computers, numerous quantum‐safe KEA protocols are also developed using various complex mathematical problems in ideal lattices. As it is an emerging and developing area, we analyze the security of recently suggested ring learning with error based KEA protocols. The goal of this study is to gain a comprehensive understanding of quantum‐safe KEA mechanisms. For our study, we have considered Dharminder's LWE‐based KEA mechanism and Dharminder and Chandran's LWE‐based KEA mechanism. These protocols enable effective communication and provide a better means for safely transmitting messages between user and server. However, we have discovered that a fundamental security weakness in these methods makes them vulnerable to signal leakage attacks (SLA). Based on our analysis, we demonstrated security weakness against SLA and provide the road‐map for secure construction.
Some enhancements to DeepKriging
Authors: Lin Ding‐Chih , Huang Hsin‐Cheng , Tzeng ShengLi
Published: March 2023

With an increased volume of spatial data, conventional spatial prediction methods have encountered significant challenges in handling complex data structures while maintaining statistical and computational efficiency. Recently, a spatial neural network method called DeepKriging has been proposed, which utilizes a set of basis functions as an embedded input to capture spatial information. In this study, we enhance this approach by using an ordered set of multi‐resolution thin plate spline basis functions, which offers ease of implementation and alleviates the challenges associated with basis function allocation, particularly when the data locations are highly irregular. The proposed method requires only the selection of the number of basis functions based on a validation dataset. In addition, we propose a robust version of DeepKriging, which is resistant to outliers. Several simulation experiments are conducted to show the advantages of our method over conventional statistical methods and the original DeepKriging approach. Finally, we apply the proposed method to a PM2.5 dataset in Taiwan.
Failure probability assessment of emergency safety barriers integrating an extension of event tree analysis and Fuzzy type‐2 analytic hierarchy process
Authors: Daas Samia , Innal Fares
Published: March 2023

Liquefied petroleum gas (LPG) storage fires and explosions occur due to uncontrolled gas leaks and the gradual breakdown of associated safety barriers. By installing an effective safety barrier, these accidents can be greatly reduced. However, this study assesses the probability of failure of emergency safety barriers (ESBs) to help decision makers understand how they can support decisions to reduce the risks associated with LPG storage. In this context, an extension of the event tree analysis is proposed named emergency event tree analysis (EETA). The aim of this paper is to develop an integrated approach that uses interval type‐2 fuzzy sets and Analytic Hierarchy Process (AHP) method and emergency event tree analysis to handle uncertainty in the failure probability assessment of emergency safety barriers (ESBs). In addition, a case study on the failure probability assessment of the emergency safety barriers of the LPG plant in Algeria based on the proposed methodology is provided and carried out to illustrate its effectiveness and feasibility. The results demonstrated the ability of interval type‐2 fuzzy sets and the AHP method to provide highly reliable results and to evaluate the failure probability of emergency safety barriers in emergencies situations. However, the classical event tree analysis (CETA) does not take into account the possibility of assessing the emergency consequences of different accident scenarios. Consequently, it only allows you to estimate the occurrence probability of accident scenarios. The results of this study show that the value of the probability of failure of the emergency safety barriers can be used to estimate the probability of occurrence of emergency consequences under different accident scenarios, improved the reliability and help prioritize emergency improvement measures. The study provides scientific and operational references for analyzing emergency consequences of the various accident scenarios in all fields such as petrochemical, maritime industry, and health occupational.
Journal watch
Authors: Kirby Mike
Published: March 2023

Professor Mike Kirby, Editor of Trends in Urology and Men's Health, picks some interesting recent papers and highlights the ‘take‐home’ messages.
Identification and exploitation of wild rye (Secale spp.) during the early Neolithic in the Middle Euphrates valley
Authors: Douché Carolyne , Willcox George
Published: March 2023

Charred remains of wild rye from five sites in the Middle Euphrates region in Syria dated to the end of the Pleistocene and the beginning of the Holocene are examined. This period spans the transition from gathering to the beginnings of cultivation. Today wild rye cannot grow in the region because temperatures and aridity are too pronounced. Wild rye grains and wild two-grained einkorn are morphologically similar, which has led to difficulties in identification; in some cases rye may have been identified as two-grained einkorn or as Triticum/Secale. In this paper, with reference to modern specimens and re-examination of charred material from Dja’de el-Mughara, Jerf el-Ahmar and Mureybet, we examine the criteria for identification and revise the results for charred caryopses and wild spikelet bases. We then present these new results which show that at the early Neolithic sites of Jerf el-Ahmar, Mureybet, Dja’de el-Mughara and Tell ‘Abr 3 wild rye frequencies are much higher than einkorn but wild barley is the dominant cereal. This is followed by discussions of how and why wild rye may have been exploited during the early Neolithic and why rye disappears from Euphrates sites with the advent of mixed farming.
Great apes reach momentary altered mental states by spinning
Authors: Lameira Adriano R. , Perlman Marcus
Published: March 2023

Among animals, humans stand out in their consummate propensity to self-induce altered states of mind. Archaeology, history and ethnography show these activities have taken place since the beginnings of civilization, yet their role in the emergence and evolution of the human mind itself remains debatable. The means through which modern humans actively alter their experience of self and reality frequently depend on psychoactive substances, but it is uncertain whether psychedelics or other drugs were part of the ecology or culture of pre-human ancestors. Moreover, (nonhuman) great apes in captivity are currently being retired from medical research, rendering comparative approaches thus far impracticable. Here, we circumvent this limitation by harnessing the breadth of publicly available YouTube data to show that apes engage in rope spinning during solitary play. When spinning, the apes achieved speeds sufficient to alter self-perception and situational awareness that were comparable to those tapped for transcendent experiences in humans (e.g. Sufi whirling), and the number of revolutions spun predicted behavioural evidence for dizziness. Thus, spinning serves as a self-sufficient means of changing body-mind responsiveness in hominids. A proclivity for such experiences is shared between humans and great apes, and provides an entry point for the comparative study of the mechanisms, functions, and adaptive value of altered states of mind in human evolution.
Structural characterization of a cytosine-rich potential quadruplex forming sequence in the EGFR promoter
Authors: Ghezzo Michele , Sissi Claudia
Published: March 2023

I-motifs are tetra-helixes that may form in cytosine-rich strands. They are based on cytosine–cytosine+ base pairs that require the N3 hemi-protonation of the nucleobases, and therefore, the stability of these non-canonical DNA arrangements depends on pH. These structures are promising targets for the development of new cancer therapies since they are enriched in the promoters of oncogenes where they can play a role in the regulation of transcription. The proximal promoter of the EGFR oncogene has multiple regions with a significant potential to form such a tetra-helix arrangement. Here, we present the thermodynamic characterization of a C-rich sequence located 37 nucleotides upstream of the transcription starting site of EGFR. We confirmed the ability of this sequence to fold into an I-motif. By applying a global analysis of calorimetric and spectroscopic data, we derived the dependency of the apparent standard Gibbs free energy change associated with the I-motif folding upon temperature and pH. The results showed that, in contrast to in silico prediction, only 4 CC+ base pairs formed while additional GC and TT base pairings were detected in the I-motif. Noteworthy, a single residue mutation at G14 largely shifts the equilibrium toward the formation of multimeric species.
Bidirectional relationships between interpretation biases, safety behaviors, and social anxiety
Authors: Prieto-Fidalgo Ángel , Calvete Esther
Published: March 2023

Theoretical models of social anxiety (SA) propose bidirectional relationships between SA, interpretation biases, and safety behaviors (Safe-B). However, longitudinal studies evaluating these bidirectional relationships are scarce. The main objective of this study was to analyze the bidirectional relationships between interpretation biases (from ambiguous situations and ambiguous faces), Safe-B, and SA. A two-time longitudinal study was carried out with the participation of 575 vocational training students (M = 19.49, SD = 2.41). Both the interpretation biases measured through ambiguous situations and ambiguous faces and the Safe-B predicted higher levels of SA in the second time. In turn, a bidirectional relationship was found between SA and Safe-B. However, no bidirectional relationships were found between interpretation biases and Safe-B and between biases and SA. Among others, the limitations of the study include the high attrition rate (30.4%) and the high proportion of male students (62.1%). The findings highlight the role of interpretation bias and Safe-B in SA. In turn, as a new initiative, the study supports the bidirectional relationship between Safe-B and SA. Implications are discussed throughout the manuscript.
Detection of geological anomalies in coal mining working faces using a scattered-wave imaging method
Authors: Zhang Jun , Yang Cai , Liu Shengdong , Li Chunyang
Published: March 2023

A concealed geological structure encountered during the excavation of a coal working face could connect the working face to high-pressure water in limestone strata, which can result in a serious or catastrophic water inrush accident. However, existing geophysical detection methods used to ensure the geological safety of working faces cannot detect small geological anomalies reliably. Based on the generalized theory of scattered waves, we have developed a novel and superior scattered wave imaging method for the detection at the roadway lateral wall, capable of wave vector extraction and multiwave imaging. In this method, the waves scattered from a geological anomaly can be dynamically and accurately extracted by the polarized filter function during the mapping processes of common scattering point (CSP) gathers. A numerical simulation was performed to study the seismic wave response characteristics of a small collapse column in a coal working face. The P and channel waves of the model were extracted and imaged using the novel imaging method. A field study of three-component seismic detection was performed in the Xuzhuang Coal Mine, demonstrating that the joint imaging of body and channel waves can detect small drop faults invisible to channel wave imaging alone. These results indicate that the proposed method can effectively image anomalous bodies on working faces in complex and noisy mine wavefields using multiwave information, providing a new approach for the reliable and timely detection of hazardous geological features hidden in working faces.
Patellofemoral Syndrome: a Review of Diagnosis and Treatment
Authors: Walli Omar , McCay Marissa , Tiu Timothy
Published: March 2023

Purpose of Review

Patellofemoral syndrome (PFS) is a common condition seen in people with anterior knee pain. This review explores patient presentations and exam maneuvers used for diagnosis, as well as established/up-and-coming treatment interventions.

Recent Findings

Pain reduction and prevention are the main goals for PFS as they negatively affect quality of life. Combination hip and knee exercises have been found to be most beneficial during therapy due to the multifactorial etiology of PFS. Combining exercise therapy with patellar taping has also shown a reduction in acute pain. Ultrasound may be used to evaluate for associated findings. Blood flow restriction and trigger point injections are options that may be helpful for pain reduction but further research is required.

PFS is a common clinical diagnosis requiring a robust patient history, supported by various physical exam maneuvers. Treatment involves a patient tailored approach, often with combinations of conservative management and interventional procedures.
MixER: linear interpolation of latent space for entity resolution
Authors: Wu Huaiguang , Li Shuaichao
Published: March 2023

Entity resolution, accurately identifying various representations of the same real-world entities, is a crucial part of data integration systems. While existing learning-based models can achieve good performance, the models are extremely dependent on the quantity and quality of training data. In this paper, the MixER model is proposed to alleviate these problems. The MixER utilizes our newly designed data augmentation method called EMix. The EMix can map discrete entity records to continuous latent space variables (e.g., probability distributions) and then linearly interpolate entity records in latent space to generate many augmented training samples. The matching model is further optimized based on the augmented data to strengthen its generalization capability. The MixER model achieves significant strengths in the data sensitivity experiments when training data is below 50. In robustness experiments, the MixER model presents an absolute performance advantage when the label noise exceeds 20%. In addition, ablation experiments demonstrate that the newly developed EMix can effectively improve the generalization ability of the matching model. The overall experimental results prove that the MixER model exhibited excellent data sensitivity and robustness over the current state-of-the-art methods.
Edward III and the War at Sea
Authors: Cushway Graham
Published: March 2023

The story of the war at sea in the reign of Edward III, including the important sea battles, and an analysis of the development of the English navy in the period.
The 3-step hedge-based valuation: fair valuation in the presence of systematic risks
Authors: Linders Daniël
Published: March 2023

In this paper, we introduce the 3-step hedge-based valuation for the valuation of hybrid claims. We consider an insurance portfolio which is exposed to traded risks, diversifiable risks and non-traded systematic risks. The class of 3-step hedge-based valuations is equivalent with the class of fair valuations. Closed-form solutions are derived for a portfolio of unit-linked contracts under the assumption of independence between financial and non-financial risks. We also consider the additive 3-step valuation and show that this additive valuation is a member of the more general class of 3-step hedge-based valuations.
A survey of handling and transportation of UK farmed deer
Authors: Pearce Samuel J , Foster Aiden P. , Knowles Toby G , Statham Poppy
Published: March 2023

Studies on the transport of deer (Cervidae), in the UK, were published > 15 years ago. A more recent study of deer transport is required to allow for assessments and improvements to the transport of farmed deer. Sixteen deer farmers participated in a survey describing their management practices related to transport. Their responses showed that most vehicles used to transport deer were designed for other livestock. Participating farmers estimated journey times to slaughter as 1–8 h, with an arithmetic mean of 4.8 (± 2.38) h. Specific concerns raised by the respondents, relating to the transport of deer, included a need for deer-specific vehicles, stop-off areas for long journeys, market locations and haulier experience. Furthermore, data were collected from two abattoirs between July 2019 and June 2020 comprising journey times, slaughter times, bruising, location of origin, vehicle type and the number of animals. In total, 4,922 deer were transported across 133 journeys (from farm to abattoir) from 61 farms. Median and range for journey length were 3.2 (0.4–9.8) h and 154.2 (7.1–462.2) km, whereas group size and time spent in the lairage were 24 (1–121) and 17.8 (10.2–68.9) h, respectively. Group size was found to be significantly associated with both the presence of bruising in a group and the amount of bruising per deer. This study provides a much-needed update on the transport of farmed deer in the UK and highlights key areas for future research including the welfare impact of transport in larger groups and for longer durations.
Strong feller and ergodic properties of the (1+1)-affine process
Authors: Chen Shukai , Li Zenghu
Published: March 2023

We prove some estimates for the variations of transition probabilities of the (1+1)-affine process. From these estimates we deduce the strong Feller and the ergodic properties of the total variation distance of the process. The key strategy is the pathwise construction and analysis of several Markov couplings using strong solutions of stochastic equations.
Modelling vortex flowfields by supercomputers with super-size memory
Authors: Rizzi Arthur
Published: March 2023

Propelled by the rapid advances in VLSI technology, supercomputers are now appearing with much larger real memory capacity than previously available. These new machines are expanding our ability to formulate very large-scale discrete models in order to discover non-linear dynamical flow behaviour. With a synergetic computational-analytical view point, we can begin to explore new and unexpected flow phenomena such as wave-like instabilities of vortices and even the onset of coherent large-scale turbulence brought about by vortex stretching.
Singular perturbation theory of longitudinal dynamic stability and response of aircraft
Authors: Xu P. Y.
Published: March 2023

The estimation of the relative orders of the coefficients in the linear differential equations of longitudinal small perturbation of aircraft is used to analyse the classical simplified theory for the short- and long-period modes by the singular perturbation methods. The leading terms of the asymptotic expansions give the eigenvalues for short- and long-period modes with fairly good accuracy, except that the damping part of the eigenvalue for the long-period mode has relative error of the order of 10%. These approximate eigenvalues are improved by the method of strained co-ordinates which accounts for most of the differences. The dynamic response due to initial disturbances of velocity, angle of attack, and angle of pitch are also derived.
Time-delay compensation in active control algorithms
Authors: Bradshaw A. , Woodhead M. A.
Published: March 2023

In this paper a direct digital control law algorithm is proposed which in addition to providing tight non-interacting tracking behaviour and excellent disturbance-rejection characteristics, provides for the compensation of finite-time delays in implementation. The control-law algorithm is defined and system stability is proved in the case of multi-input multi-output linear systems. The theory is synthetic and leads directly to the determination of the appropriate controller matrices.

The theory is illustrated by the presentation of simulation results in which the aircraft is represented by an analogue computer and the digital control system is implemented on a microprocessor. In the simulation study the controller is required to effect fuselage pitch pointing and vertical translation manoeuvres for the analogue computer representation of the YF-16 aircraft. It is shown that tight non-interacting control is achievable even when the control implemented is delayed by 0·1 seconds.
A stress intensity factor solution due to holes ahead of growing cracks in thin sheet material
Authors: Young J. B. , Campbell P. N.
Published: March 2023

The variation of the Crack Stress Intensity Factor (SIF), for two cracks growing from one hole only in an array of holes in an isotropic material under uni-axial tension has been studied. The effect of the fastener hole ahead of the growing crack was found to give an increase in the SIF only when the crack was within about one and a half diameters of the approached hole edge, compared with the level predicted by considering a single central hole in a plate. An equation suitable for inclusion in a crack growth program has been derived from the research results.
The application of mass spectrometry to the study of mixing processes in confined and unconfined gas flows
Authors: Ransom E. C. P. , Barnes J. H.
Published: March 2023

This paper describes a novel flow tracing technique which has been developed to obtain data on mixing and dispersion processes in gaseous flow systems. Tracer gas is injected at low flow rates into an air stream. Choice of tracer gas — primary fluid combination in relation to gas properties and detection techniques is discussed. The mode of operation of the mass spectrometer is described together with the sampling system. Analysis of samples drawn from the flow field provides tracer gas concentration profiles throughout the flow and these may be used to yield information on mixing rates. Two examples are given which illustrate the use of the method.
Transonic flow calculations around isolated inlet configurations
Authors: Peace A. J.
Published: March 2023

A numerical method for calculating transonic flow around general inlet configurations is presented. The method is based on a finite volume potential flow algorithm with enhancements to reduce truncation errors. An approximate factorisation iterative scheme is employed and the computer code is written to take advantage of the architecture of a vector computer. The method has also been coupled with an integral boundary layer method to take into account viscous effects on the inlet surface. Results are presented for a number of configurations which are representative of current design trends, at both take-off and cruise conditions. Comparison with experimental data shows favourable agreement. The method is shown to be accurate, reliable and cheap to run.
A lock-in effect in the flow
over two cylinders
Authors: Barnes F. H. , Baxendale A. J. , Grant I.
Published: March 2023

Measurements are presented of the frequency of vortex shedding from two circular cylinders in a staggered arrangement. Seven different cylinders were used in turn as the upstream cylinder and the ratio of the diameter of the upstream cylinder to that of the downstream cylinder ranged from 0·00422 to 0·571. For a constant free-stream velocity changing the upstream cylinder changed the frequency of vortex shedding from the cylinder. It was found that the frequency of vortex shedding from the downstream cylinder N synchronised with that of the upstream cylinder n over a range of the latter frequency. When the frequencies were synchronised the ratio of the frequencies was given by n/N = 2. This behaviour is characteristic of a lock-in process.

Lock-in was found at each of the four upstream cylinder positions tried. However, it was only when the upstream cylinder position was such that the upstream cylinder only weakly affected the flow about the downstream cylinder that lock-in was accompanied by a decrease in the base pressure. The time-mean drag force then increased with lock-in, but by a small amount only. On the other hand the fluctuating lift force increased substantially.
The effect of atmospheric turbulence on the dispersion of unguided missiles
Authors: Curcin M. , Harris R. I.
Published: March 2023

A technique for calculating the dispersion of unguided missiles due to strong turbulent wind is presented. The three components of turbulent wind velocity are simulated along a trajectory by means of a moving average process according to Box and Jenkins. Variations of the statistics of turbulent wind with height are taken into account. A six degree of freedom program is used to calculate a trajectory. The effect of turbulent wind on both powered and unpowered flight is considered. The results of the calculation for two types of missiles are presented.
The influence of roughness trips upon boundary-layer transition Part 2. Characteristics of single spherical trips
Authors: Gibbings J. C. , Goksel O. T. , Hall D. J.
Published: March 2023

Following Part 1, experimental data is given for the boundary-layer flow past single roughness trips of spherical shape. Correlations are given for the start and end of transition, for the recovery position and for the effective origin of the turbulent layer. There is evidence of a spanwise array of vortices which are found to influence both the downstream turbulent layer and the wedge growth of turbulence.
An integral method for calculating the effects on turbulent boundary-layer development of sweep and taper
Authors: Ashill P. R , Smith P. D
Published: March 2023

A simple modification is described to the integral method of P. D. Smith for calculating turbulent boundary layers on infinite yawed wings to allow for wing planform taper. A comparison has been made between the modified and general methods for calculating three-dimensional boundary layers. This suggests that the modified method is useful for obtaining a rapid indication of the separate effects on the boundary layer of wing sweep and planform taper.
The influence of roughness trips upon boundary-layer transition. Part 1: Characteristics of wire trips
Authors: Gibbings J. C. , Goksel O. T. , Hall D. J.
Published: March 2023

This report gives extended data for the flow past roughness trips to provoke boundary-layer transition. This first Part reports work on wire trips giving data for the forces on the wire, the positions of recovery and effective origin of the turbulent layer, the length of the separation bubble and the beginning and end of transition. Parts 2 and 3 describe similar work on spherical roughness trips, used singly and in rows, looking in more detail at the spanwise variations in the downstream boundary-layer.
Extension of hot air balloon flight duration through adaption of balloon surface characteristics
Authors: Hallmann W.
Published: March 2023

Two hundred years ago the first manned balloon launch was attempted. On 21st November 1783 the hot air balloon, Montgolfiere, carried two men, the adventurer Pilatre von Roxier and the Marquis D’Arlandes, nine kilometres during their twenty minute flight.

The history of flight continued with many ambitious and inventive men. Among them were Graf Zeppelin, famous for airships, Otto Lilienthal for motorless flight, and the Wright brothers for the first powered flight. Since then the development went further until today large scale aircraft have become commonplace. Tomorrow, space flight could be just as common. Who dares say no to the technology that has brought us today’s living comforts?

The following contribution deals with an actual problem in present day hot air balloon construction.
The influence of roughness trips upon boundary-layer transition Part 3. Characteristics of rows of spherical transition trips
Authors: Gibbings J. C. , Goksel O. T. , Hall D. J.
Published: March 2023

Following Parts 1 and 2 of this experimental study the effects of rows of spherical roughness elements upon transition of the boundary layer are now described. Data presented includes that for the start of the end of transition, the effect of spacing of the roughness elements, the effective origin of the turbulent boundary layer and its development and the spanwise variations across the turbulent boundary layer.
Installation aerodynamics of ejectors in combat aircraft
Authors: Knott P. G. , Cundy D. N.
Published: March 2023

Attention is focused on the installation aerodynamic aspects, rather than ejector design itself, of ejector augmentors installed in combat aircraft as part of the lift and propulsion system.

It is indicated that in the case of the combat aircraft required to perform vertical land but not VTO, the installed thrust is such that only a small level of augmentation is required. The reason for installing an ejector is that it is capable of providing this augmentation together with a benign ground footprint. The design problems are seen to be those of relatively large volume and ensuring satisfactory aerodynamic performance in all relevant flight regimes.

The installation aerodynamic problems focus on the inlet and exhaust. Performance is very sensitive to intake pressure recovery with the critical area being at the start of the landing transition. In the second case, the problem is that of providing a degree of thrust vectoring for the large low pressure exhaust to provide adequate transition performance in the face of considerable intake momentum drag.
An analytical redundancy scheme for flight control systems
Authors: McLean D. , Alkhatib K.
Published: March 2023

The normal practice for achieving some specified degree of reliability in automatic flight control systems has been to use methods which employ several identical feedback channels. The use of such methods requires additional sensors and other hardware components. Since such an approach has become increasingly expensive to implement, and attracts operational costs, owing to the increased weight arising from the extra equipment, any method is attractive which achieves the same degree of reliability through the use of only a single hardware path for each feedback channel. This implies the employment of special software techniques for both detecting any channel failures and reconstructing the feedback signals, which are then missing as a result of those failures. Such a scheme is presented and discussed in the paper and a number of results obtained from digital simulation are also presented to illustrate the effectiveness of the scheme for a wide variety of sensor failure conditions. The sensitivity of the scheme to initial errors in the estimation process, to the dynamic nature of the motion sensors, and to errors in the mathematical model of the aircraft dynamics, is also illustrated and discussed.
The effect of freestream turbulence on pressure fluctuations in transonic flow
Authors: Raghunathan S. , McAdam R.J.W.
Published: March 2023

Pressure fluctuation measurements were made on an 18% thick biconvex aerofoil in the region of shock boundary layer interaction at various levels of free stream flow unsteadiness. Experiments were performed with free transition and transition fixed models at a shock Mach number of 1.44 and blade chord Reynolds number of 1.6 x 105. The transition free model with a laminar boundary layer showed the presence of periodic flows at low turbulence levels which disappeared with the increase in turbulence levels. The general effect of free stream turbulence on transition fixed model is one of broad band amplification of pressure fluctuation levels in the region of shock interactions.
Derivatives and Market (Il)liquidity
Authors: Huang Shiyang , Yueshen Bart Z. , Zhang Cheng
Published: March 2023

We study how derivatives (with nonlinear payoffs) affect the underlying asset’s liquidity. In a rational expectations equilibrium, informed investors expect low conditional volatility and sell derivatives to the others. These derivative trades affect different investors’ utility differently, possibly amplifying liquidity risk. As investors delta hedge their derivative positions, price impact in the underlying drops, suggesting improved liquidity, because informed trading is diluted. In contrast, effects on price reversal are ambiguous, depending on investors’ relative delta hedging sensitivity (i.e., the gamma of the derivatives). The model cautions of potential disconnections between illiquidity measures and liquidity risk premium due to derivatives trading.
Epidemiological characteristics, spatial clusters and monthly incidence prediction of hand, foot and mouth disease from 2017 to 2022 in Shanxi Province, China
Authors: Ma Yifei , Xu Shujun , Dong Ali , An Jianhua , Qin Yao , Yang Hui , Yu Hongmei
Published: March 2023

Hand, foot and mouth disease (HFMD) is a common infection in the world, and its epidemics result in heavy disease burdens. Over the past decade, HFMD has been widespread among children in China, with Shanxi Province being a severely affected northern province. Located in the temperate monsoon climate, Shanxi has a GDP of over 2.5 trillion yuan. It is important to have a comprehensive understanding of the basic features of HFMD in those areas that have similar meteorological and economic backgrounds to northern China. We aimed to investigate epidemiological characteristics, identify spatial clusters and predict monthly incidence of HFMD. All reported HFMD cases were obtained from the Shanxi Center for Disease Control and Prevention. Overall HFMD incidence showed a significant downward trend from 2017 to 2020, increasing again in 2021. Children aged < 5 years were primarily affected, with a high incidence of HFMD in male patients (relative risk: 1.316). The distribution showed a seasonal trend, with major peaks in June and July and secondary peaks in October and November with the exception of 2020. Other enteroviruses were the predominant causative agents of HFMD in most years. Areas with large numbers of HFMD cases were primarily in central Shanxi, and spatial clusters in 2017 and 2018 showed a positive global spatial correlation. Local spatial autocorrelation analysis showed that hot spots and secondary hot spots were concentrated in Jinzhong and Yangquan in 2018. Based on monthly incidence from September 2021 to August 2022, the mean absolute error (MAE), mean absolute percentage error (MAPE), and root mean square error (RMSE) of the long short-term memory (LSTM) and seasonal autoregressive integrated moving average (SARIMA) models were 386.58vs.838.25, 2.25vs.3.08, and 461.96vs.963.13, respectively, indicating that the predictive accuracy of LSTM was better than that of SARIMA. The LSTM model may be useful in predicting monthly incidences of HFMD, which may provide early warnings of HFMD epidemics.
Spatio–Numerical Mapping in 3D
Authors: Bourgaux Louis , De Hevia Maria-Dolores , Charras Pom
Published: March 2023

Abstract: The close link between number and space is illustrated by the Spatial Numerical Association of Response Codes (SNARC) effect. The current research focuses on the flexibility of the SNARC across three dimensions. Shaki and Fischer (2018) pointed out that spatial attributes of stimuli and response effectors can favor an ad hoc spatial representation. In this paper, we aimed to broaden this perspective using two Go/NoGo experiments with digits being presented at two spatial locations while a central response was required. In Experiment 1, stimuli appeared either to the left or right (horizontal) and below or above fixation (vertical). In Experiment 2, as the monitor was laying down flat on the desk, stimuli appeared either to the left or right (horizontal) and either close or far from the observer (midsagittal). The results of Experiment 1 show significant effects for the two dimensions (horizontal, vertical), while in Experiment 2, we observe only a barely significant effect for the sagittal axis. We interpret these findings as showing (1) the importance of motor response spatialization in eliciting the SNAs and (2) the dominance of the vertical axis over the horizontal when the spatial component of the motor response is removed.
An Interference Model for Low Frequency Radio Spectrometer Onboard Chang’e‐4 Mission
Authors: Liu Chen‐di , Su Yan , Zhou Jian‐feng
Published: March 2023

As one of the critical payloads of the Chang’e‐4 mission, the low‐frequency radio spectrometer (LFRS) has yet to produce significant and influential scientific results. The main reason is that the observation data has considerable interference, mainly from the instrument platform, and presents a comb structure in the spectrum space. On this basis, combining the configuration of three antennas orthogonal to each other of the instrument, a single‐frequency interference mathematical model is proposed, solved, and evaluated in this paper. The analysis results show that the single‐frequency interference model has high fitting accuracy under a certain noise level. In the future, the interference model can be gradually extended from single‐frequency to multi‐frequency, and the actual state of instrument interference can be progressively approximated. Finally, under the requirement of a certain SNR, the interference can be accurately fitted so that the platform interference can be separated from the observation data collected by the instrument, making the effective cosmic signal stand out. In this way, the original scientific objective of the payload is expected to be achieved.