bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic tests for medullary thyroid carcinoma: an umbrella review
Authors: Trimboli Pierpaolo , Mian Caterina , Piccardo Arnoldo , Treglia Giorgio
Published: March 2023

Purpose

To summarize the more robust evidence about the performance of tools useful for diagnosis of medullary thyroid carcinoma (MTC) such as calcitonin (Ctn) and other circulating markers, ultrasound (US), fine-needle aspiration (FNA), and other imaging procedures.

Methods

This systematic review of systematic reviews was carried out according to a predefined protocol. A search string was created. An electronical comprehensive search of literature was performed on December 2022. Quality assessment of eligible systematic reviews was performed and main findings were described.

Results

Twenty-three systematic reviews were included and several findings were achieved. Ctn is the most reliable diagnostic marker of MTC with no evidence of improvement with stimulation test. CEA doubling time is more reliable than Ctn in identifying MTC with poorer prognosis. US sensitivity is suboptimal in MTC and only just over half of cases are at high risk according to Thyroid Imaging And Reporting Data Systems. Cytology can correctly detect MTC in just over half of cases and measuring Ctn in washout fluid from FNA is necessary. PET/CT is useful for detecting recurrent MTC.

Conclusions

Future guidelines of both thyroid nodule management and MTC diagnosis should consider these evidence-based data.
Numerical investigation of labyrinth-shaft spillway
Authors: Aydin M. Cihan , Ulu Ali Emre
Published: March 2023

In the present study, a new type of hybrid spillway termed labyrinth-shaft spillway was introduced to improve the discharge capacity and efficiency of the spillway. An advanced computational fluid dynamics (CFD) technique was used to analyze the performance of the labyrinth-shaft spillway. The hydraulic performance of the new model was investigated for different labyrinth geometries with a verified computational model. The analysis results demonstrated that the discharge capacity of the labyrinth-shaft spillway was better when compared to that of the conventional shaft spillways with the same weir heads. The discharge coefficient that reflects the efficiency of the labyrinth-shaft spillway was also much better when compared to the conventional spillway, while the opposite was observed with relatively small nappe heads. Similarly, the comparison with the findings of previous studies on labyrinth weirs in the literature demonstrated that labyrinth-shaft spillways performed better when compared to the conventional labyrinth weirs in-channel flow conditions, especially with high nappe heads. A new formula was also developed in the present study with regression analysis conducted on the collected data to calculate the discharge coefficients of the labyrinth-shaft spillway for H/P > 0.2.
In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients
Authors: Rasooli Reza , Giljarhus Knut Erik Teigen , Hiorth Aksel , Jolma Ingunn Westvik , Vinningland Jan Ludvig , de Lange Charlotte , Brun Henrik , Holmstrom Henrik
Published: March 2023

Purpose

The Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients.

Methods

A self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance.

Results

The assist device provided a significant IVC pressure drop of more than 3.2 mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1 mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature.

Conclusions

A self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.
Heartbeat detector from ECG and PPG signals based on wavelet transform and upper envelopes
Authors: Merino-Monge Manuel , Castro-García Juan Antonio , Lebrato-Vázquez Clara , Gómez-González Isabel María , Molina-Cantero Alberto Jesús
Published: March 2023

The analysis of cardiac activity is one of the most common elements for evaluating the state of a subject, either to control possible health risks, sports performance, stress levels, etc. This activity can be recorded using different techniques, with electrocardiogram and photoplethysmogram being the most common. Both techniques make significantly different waveforms, however the first derivative of the photoplethysmographic data produces a signal structurally similar to the electrocardiogram, so any technique focusing on detecting QRS complexes, and thus heartbeats in electrocardiogram, is potentially applicable to photoplethysmogram. In this paper, we develop a technique based on the wavelet transform and envelopes to detect heartbeats in both electrocardiogram and photoplethysmogram. The wavelet transform is used to enhance QRS complexes with respect to other signal elements, while the envelopes are used as an adaptive threshold to determine their temporal location. We compared our approach with three other techniques using electrocardiogram signals from the Physionet database and photoplethysmographic signals from the DEAP database. Our proposal showed better performances when compared to others. When the electrocardiographic signal was considered, the method had an accuracy greater than 99.94%, a true positive rate of 99.96%, and positive prediction value of 99.76%. When photoplethysmographic signals were investigated, an accuracy greater than 99.27%, a true positive rate of 99.98% and positive prediction value of 99.50% were obtained. These results indicate that our proposal can be adapted better to the recording technology.
The impact of COVID-19 pandemic on breast surgery in Italy: a multi-centric retrospective observational study
Authors: Sgarzani R. , Macrì G. , Gurrado A. , Curcio A. , De Lorenzi F. , Galimberti V. , Garusi C. , Bocchiotti M. , Roncella M. , Rovera F. , Caputo G. , Sgarella A. , Adesi L. Barone , Terribile D. , Nonnis R. , Frittelli P. , Cagli B. , Tenna S. , Baldelli I. , Cordova A. , Elia R. , Salgarello M.
Published: March 2023

COVID-19 pandemic had an impact on surgical activities. The aim of this multi-centric, retrospective study was to evaluate the impact of the COVID-19 pandemic on breast surgery. The patients who operated during the pre-pandemic year 2019 were compared to those operated in 2020. Fourteen Breast Care Units provided data on breast surgical procedures performed in 2020 and 2019: total number of breast-conserving surgery (BCS), number of 1st level oncoplastic breast surgery (OBS), number of 2nd level OBS; total number of mastectomies, mastectomies without reconstruction, mastectomies with a tissue expander, mastectomies with direct to implant (DTI) reconstruction, mastectomies with immediate flap reconstruction; total number of delayed reconstructions, number of expanders to implant reconstructions, number of delayed flap reconstructions. Overall 20.684 patients were included: 10.850 (52.5%) operated during 2019, and 9.834 (47.5%) during 2020. The overall number of breast oncologic surgical procedures in all centers in 2020 was 8.509, compared to 9.383 in 2019 (− 9%). BCS decreased by 744 cases (− 13%), the overall number of mastectomies decreased by 130 cases (− 3.5%); mastectomy-BCS ratio was 39–61% in 2019, and 42–58% in 2020. Regarding immediate reconstructive procedures mastectomies with DTI reconstruction increased by 166 cases (+ 15%) and mastectomies with immediate expander reconstruction decreased by 297 cases (− 20%). Breast-delayed reconstructive procedures in all centers in 2020 were 142 less than in 2019 (− 10%). The outburst of the COVID-19 pandemic in 2020 determined an implemented number of mastectomies compared to BCS, an implemented number of immediate breast reconstructions, mainly DTI, and a reduction of expander reconstruction.
Tax evasion and tax amnesties in regional taxation
Authors: Angeli Andrea , Lattarulo Patrizia , Palmieri Eugenio , Pazienza Maria Grazia
Published: March 2023

Italian governments have frequently chosen tax amnesties or concessions, with the twofold purpose of creating new budget resources and cancelling irredeemable debts. Such course of action constitutes a “shortcut” policy in terms of fighting tax evasion, which is a matter less popular among voters and more demanding in terms of efficiency and political continuity. This paper investigates the effects of the 2016–2019 tax concession, bringing empirical evidence based on the car tax paid to the Tuscany Region. The car tax is the main source of regional fiscal autonomy in Italy. In terms of revenue recovery, we found a net amount of only 1.6% of the unpaid taxes accrued. A difference-in-difference (DiD) analysis of the effects on compliance showed that those who took advantage of the tax amnesty in the past, when cheating again, were more likely to default on their tax debts, as compared to those who did not join the amnesty program. Therefore, our analysis provides original evidence of a very low budget recovery and confirms the results of literature according to which tax amnesties impact negatively on taxpayers’ behaviour.
Facilitators and barriers to creating a culture of academic integrity at secondary schools: an exploratory case study
Authors: Çelik Özgür , Razı Salim
Published: March 2023

Academic integrity is a vital pedagogical responsibility that educational institutions should explicitly address. One of the best ways to uphold academic integrity is to create a culture of academic integrity throughout the school. This is especially imperative at high schools where students develop their moral identity because students who act dishonestly at high school will likely behave accordingly in post-secondary education and ultimately be dishonest in familial and professional settings. Creating a culture of academic integrity is a challenging, long and multifaceted journey. In this respect, this exploratory case study set out to create a culture of academic integrity at a high school in Türkiye and explore what facilitates and impedes the process. We followed Stephens’ (2016) Multilevel Intervention Model and implemented a School-Wide Education program to guide us through the process. We conducted various activities throughout one academic year, from seminars to competitions. At the end of the term, we conducted individual and focus group interviews with the members of the school community and analyzed the interview data to identify facilitators and barriers of the process. The analysis yielded five facilitators (1) creating buy-in, (2) administrative embracement and support, (3) activities that promote student involvement, (4) external expert and school collaboration as praxis, and (5) policy as the blueprint and five barriers (1) deficiencies in responding academic misconduct, (2) prioritization of academic success over academic integrity, (3) teacher resistance against change, (4) exam-based assessment design, and (5) timing of the activities. Each theme was discussed in detail, and recommendations were made for high schools which set out on a journey of creating academic integrity culture.
Cynicism Toward Change and Career Stage: An Exploration of Work Environment and Organizational Based Characteristics Among Prison Officers in Ghana
Authors: Akoensi Thomas D. , Amankwah-Amoah Joseph
Published: March 2023

Prison officer cynicism toward change (CTC) has received limited attention in the penal literature. In the global south, there has been very limited research on CTC among prison officers. In addressing this research gap, we utilized data from prison officers based in low- and medium- security prisons in Ghana to assess the level of CTC and whether the levels of reported CTC differed across different career stages. We also examine the impact of individual, work-environment, and organizational predictors on CTC across career stages. Our results reveal similar levels of moderate CTC among prison officers at all career stages. Organizational-based factors were stronger predictors of CTC than work-environment variables. Input into decision making was the only predictor of CTC across all career stages. We identify and examine a number of vital contributions to theory and practice.
Changes on local travel behaviors under travel reduction-related interventions during COVID-19 pandemic: a case study in Hong Kong
Authors: Shang Shujia , Jia Wei , Zhang Shiyao , Su Boni , Cheng Reynold , Li Yuguo , Zhang Nan
Published: March 2023

The emerging Omicron variant poses a serious threat to human health. Public transports play a critical role in infection spread. Based on the data of nearly 4 billion smartcard uses, between January 1, 2019 and January 31, 2021 from the Mass Transit Railway Corporation of Hong Kong, we analyzed the subway travel behavior of different population groups (adults, children, students and senior citizens) due to the COVID-19 pandemic and human travel behavior under different interventions (e.g. work suspension, school closure). Due to the pandemic, the number of MTR passengers (the daily number of passengers in close proximity in subway carriages) decreased by 37.4% (40.8%) for adults, 80.3% (78.5%) for children, 71.6% (71.6%) for students, and 33.5% (36.1%) for senior citizens. Due to work from home (school suspension), the number of contacted adults (students/children) in the same carriage during the rush hours decreased by 39.6% (38.6%/43.2%). If all workers, students, and children were encouraged to commute avoiding rush hours, the possible repeated contacts during rush hour of adults, children and students decreased by 73.3%, 77.9% and 79.5%, respectively. Since adults accounted for 87.3% of the total number of subway passengers during the pandemic, work from home and staggered shift pattern of workers can reduce the infection risk effectively. Our objective is to find the changes of local travel behavior due to the pandemic. From the perspective of public transports, the results provide a scientific support for COVID-19 prevention and control in cities.
Potassium Fertilizer Rate Recommendations: Does Accounting for Soil Stock of Potassium Matter?
Authors: Oliver Kimberly B. , Popp Michael P. , Fang Di , Anderson John D. , Slaton Nathan A. , Drescher Gerson L. , Roberts Trenton L. , Thompson Jada
Published: March 2023

Profitability, yield, and fertilizer use are compared across three different potassium (K) fertilizer rate recommendation ideologies. Existing agronomic, “build and maintain” rate recommendations (KE) are compared to profit-maximizing rates with and without taking long-run soil-test K (STK) implications into account. Regardless of starting STK, K use equilibrated over the course of 3 years irrespective of ideology. Since taking long-run STK into account did not alter ending STK and only led to a miniscule yield effect, we encourage producers to use annual profit-maximizing K rates that were 3–11% lower than KE rates and generated more profit with minimal yield loss.
Going Back to the Roots: Indigenous Language, Media Performance, and Change in Kenya
Authors: Kanana Erastus Fridah , Kinyua Ann H. G.
Published: March 2023

The introduction of indigenous languages to Kenyan media, following pre- and post-independence realities, opened the floodgate of communications within the country, with both positive and negative consequences. Indigenous languages found expression in creative works, civic communication, and other areas previously reserved solely for English and Kiswahili. Kanana and Kinyua discuss this trajectory within the context of media liberalization, digital migration, and gains from the period of state crackdown on media to the promulgation of the 2010 Kenyan Constitution and devolution of government units reflecting traditional boundaries. Employing secondary research methodologies, they argue the advantages of indigenous languages in the media over the disadvantages highlighted in the literature.
Mixing properties of erasing interval maps
Authors: CORONA DARIO , DELLA CORTE ALESSANDRO
Published: March 2023

We study the measurable dynamical properties of the interval map generated by the model-case erasing substitution$\rho $, defined by$$ \begin{align*} \rho(00)=\text{empty word},\quad \rho(01)=1,\quad \rho(10)=0,\quad \rho(11)=01. \end{align*} $$We prove that, although the map is singular, its square preserves the Lebesgue measure and is strongly mixing, thus ergodic, with respect to it. We discuss the extension of the results to more general erasing maps.
Zero entropy actions of amenable groups are not dominant
Authors: LOTT ADAM
Published: March 2023

A probability measure-preserving action of a discrete amenable group G is said to be dominant if it is isomorphic to a generic extension of itself. Recently, it was shown that for
$G = \mathbb {Z}$
, an action is dominant if and only if it has positive entropy and that for any G, positive entropy implies dominance. In this paper, we show that the converse also holds for any G, that is, that zero entropy implies non-dominance.
Conference Summary of the Symposium on Foreign-Related Commercial and Maritime Trials of Courts Nationwide (Sup. People's Ct. China)
Authors: Gan Yong
Published: March 2023

China's foreign judgment recognition and enforcement regime has been the least developed part of its private international law, as opposed to jurisdiction and choice of law. The regime remained almost immutable over three decades from the 1980s, even though the civil procedure law that established it went through several revisions. Under the present Civil Procedure Law (CPL), the regime consists of rules regarding qualified applicants, legal bases, and refusal grounds for recognition and enforcement. According to these rules, the creditor of an effective foreign judgment or the foreign court rendering it may seek its recognition and enforcement before a Chinese court. The Chinese court shall review the application based on international treaties China has concluded or acceded to, or the principle of reciprocity. If the effective foreign judgment has not proven to contravene the fundamental principles of Chinese laws and the sovereignty, security, and public social interests of the state, it will be recognized and enforced; otherwise, it will not receive recognition and enforcement.
Ilkhanid Wood Carvings in the Mountain Villages between Kashan and Natanz
Authors: Ghiasian Mohamad Reza , Mashhadi Nooshabadi Mohammad
Published: March 2023

This paper surveys some wood carvings belonging to four mosques in the villages of Firizhand, Quhrud, Abyana, and Barzuk. Carved between the years 700/1300-1 and 705/1305–6, they consist of architectural elements such as doors, columns, and capitals. The recently found woodwork evidence from the demolished Jamiʿ mosque of Barzuk reveals that this building and its decorations were executed by a multiskilled artist, who was most likely a descendant of Abu Zayd. Moreover, the newly discovered columns from the Masjid-i ʿAli in Quhrud show that, in contrast to what was previously thought, the current building is not contemporary with its dated door and was erected in later centuries. Interestingly, these wooden mosques were built during the last years of Ghazan Khan's rule and witness his order to construct mosques in all the villages of the country. This woodwork offers significant insight into the artistic and cultural situation of the early fourteenth century.
Entrainment mechanism of turbulent synthetic jet flow
Authors: Xu Congyi , Long Yanguang , Wang Jinjun
Published: March 2023

Synthetic jets have received extensive attention due to their superior mixing property. However, its mechanisms have not been investigated from the perspective of the turbulent/non-turbulent interface (TNTI). To shed new light on this issue, the entrainment and TNTI properties of a synthetic jet are experimentally investigated and compared with a continuous jet at

$Re_j = 3150$

. The fuzzy clustering method is applied to select an appropriate vorticity threshold to detect the TNTI. Statistically, it is revealed that the entrainment coefficients of the two jets significantly differ in the near field, while they become almost identical in the far field. Instead of the vortex ring, the ‘breakdown of the vortex ring’ enhances the entrainment in the present synthetic jet. Instantaneously, the TNTI more violently fluctuates in the near field of the synthetic jet, which leads to a larger fluctuation in the TNTI radial position, a higher fractal dimension and enhanced local entrainment. Moreover, the transition of the probability density function of the TNTI orientation from the unimodal distribution in the near field to the bimodal distribution in the far field is found in both jets. The multi-scale analysis reveals a new mechanism for the bimodal distribution caused by the TNTI-thickness-scale structures.
When does an impacting drop stop bouncing?
Authors: Sanjay Vatsal , Chantelot Pierre , Lohse Detlef
Published: March 2023

Non-wetting substrates allow impacting liquid drops to spread, recoil and take-off, provided they are not too heavy (Bianceet al.,J. Fluid Mech., vol. 554, 2006, pp. 47–66) or too viscous (Jhaet al.,Soft Matt., vol. 16, no. 31, 2020, pp. 7270–7273). In this article, using direct numerical simulations with the volume of fluid method, we investigate how viscous stresses and gravity oppose capillarity to inhibit drop rebound. Close to the bouncing to non-bouncing transition, we evidence that the initial spreading stage can be decoupled from the later retraction and take-off, allowing us to understand the rebound as a process converting the surface energy of the spread liquid into kinetic energy. Drawing an analogy with coalescence-induced jumping, we propose a criterion for the transition from the bouncing to the non-bouncing regime, namely by the condition${Oh}_{c} + {Bo}_{c} \sim 1$, where${Oh}_{c}$and${Bo}_{c}$are the Ohnesorge number and Bond number at the transition, respectively. This criterion is in excellent agreement with the numerical results. We also elucidate the mechanisms of bouncing inhibition in the heavy and viscous drop limiting regimes by calculating the energy budgets and relating them to the drop's shape and internal flow.
Exponential asymptotics and the generation of free-surface flows by submerged line vortices
Authors: Shelton Josh , Trinh Philippe H.
Published: March 2023

There has been significant recent interest in the study of water waves coupled with non-zero vorticity. We derive analytical approximations for the exponentially small free-surface waves generated in two dimensions by one or several submerged point vortices when driven at low Froude numbers. The vortices are fixed in place, and a boundary-integral formulation in the arclength along the surface allows the study of nonlinear waves and strong point vortices. We demonstrate that, for a single point vortex, techniques in exponential asymptotics prescribe the formation of waves in connection with the presence of Stokes lines originating from the vortex. When multiple point vortices are placed within the fluid, trapped waves may occur, which are confined to lie between the vortices. We also demonstrate that, for the two-vortex problem, the phenomenon of trapped waves occurs for a countably infinite set of values of the Froude number. This work will form a basis for other asymptotic investigations of wave–structure interactions where vorticity plays a key role in the formation of surface waves.
The Lyman–Huggins interpretation of enstrophy transport
Authors: Terrington S.J. , Hourigan K. , Thompson M.C.
Published: March 2023

The Lighthill–Panton and Lyman–Huggins interpretations of vorticity dynamics are extended to the dynamics of enstrophy. There exist two competing definitions of the vorticity current tensor, which describes the flow rate of vorticity in the fluid interior, and the corresponding boundary vorticity flux, which represents the local vorticity creation rate on a boundary. It is demonstrated that each definition of the vorticity current tensor leads to a consistent set of definitions for the enstrophy current, boundary enstrophy flux and the enstrophy dissipation term. This leads to two alternative interpretations of vorticity and enstrophy dynamics: the Lighthill–Panton and Lyman–Huggins interpretations. Although the kinematic evolution of the vorticity and enstrophy fields are the same under each set of definitions, the dynamical interpretation of the motion generally differs. For example, we consider the Stokes flow over a rotating sphere, and find that the flow approaches a steady state where, under the Lyman–Huggins interpretation, there is no enstrophy creation or dissipation. Under the Lighthill–Panton interpretation, however, the steady-state flow features a balance between the continuous generation and subsequent dissipation of enstrophy. Moreover, the Lyman–Huggins interpretation has previously been shown to offer several benefits in understanding the dynamics of vorticity, and therefore it is beneficial to extend this interpretation to the dynamics of enstrophy. For example, the Lyman–Huggins interpretation allows the creation of vorticity, and therefore enstrophy, to be interpreted as an inviscid process, due to the relative acceleration between the fluid and the boundary.
Working from home during lockdown: the impact on performance and wellbeing
Authors: Smollan Roy K. , Morrison Rachel L. , Cooper-Thomas Helena D.
Published: March 2023

The experience of working from home changed drastically with the arrival of COVID-19. Compared to pre-pandemic experiences, key differences included the vast number of people involved, its involuntary nature, the suddenness of its implementation, its lengthy duration, and the presence of others at home. The demands of this form of remote work during lockdown have partly been mitigated by the resources employees have accessed. This study aimed to investigate the factors impacting employee performance and wellbeing while compulsorily working from home during New Zealand's first nationwide lockdown. We analyzed qualitative data gathered from employees in two organizations. The resulting aggregate dimensions across both demands and resources include organizational factors, furniture and technology factors, and individual factors. Given the ongoing nature of COVID-19 we identify new research directions for investigating remote work, and practical implications focusing on suitable home furniture and technology, plans for future remote work, and supporting employees.
Targeting BCR-ABL1-positive leukaemias: a review article
Authors: Leak Steven , Horne Gillian A. , Copland Mhairi
Published: March 2023

Treatment and understanding of BCR::ABL1-positive leukaemias is a precision medicine success story. Our appreciation of the BCR::ABL1 gene and resulting BCR::ABL1 oncoprotein in chronic myeloid leukaemia (CML) and Philadelphia chromosome-positive (Ph+) acute leukaemias, has led to treatment advances associated with exceptional improvements in patient outcomes with normal life expectancy for many patients with chronic phase (CP-)CML. However, despite these major therapeutic advances, the management of Ph+ leukaemias remains complex, with development of specific resistance mutations on treatment, as well as the need for lifelong therapy in most patients due to the persistence of CML stem cells despite prolonged tyrosine kinase inhibitors (TKIs) treatment. BCR::ABL1-specific TKIs are associated with chronic toxicities affecting quality-of-life in many patients but can also result in more serious pulmonary and cardiovascular complications. Dose optimisation is increasingly being used to manage side effects and maintain molecular response in CML patients. Here, we review the development of BCR::ABL1-specific TKIs from the discovery of imatinib in 1996 to the more recent second- and third-generation TKIs and emerging specifically targeting the ABL myristoyl pocket (STAMP) inhibitors. We will also evaluate the current evidence for treatment of BCR::ABL1-positive leukaemias, including TKI discontinuation in optimally responding CP-CML patients.
Aerodynamic design methods for transonic wings
Authors: R. C. Lock
Published: March 2023

A review is given of current methods in theoretical aerodynamics which are useful in the design of aircraft wings for subsonic and transonic speeds. These are of two basic types:

(A) direct methods for calculating the flow over a givenwing shape. In the design process, these can be used to obtain a rapid estimate of the effect of a specified change in wing shape. The most practical methods of this type make use of the viscous/inviscid interaction technique; some recent methods are described and examples are given of their use, both in two and three dimensions, including comparisons with experiment.

(B) inverse methods in which the shape is calculated explicitly, as a result of either (a) specifying the surface pressure distribution on the wing, or (b) requiring that some suitable ‘target’ function, usually the drag/lift ratio, shall be a minimum. At present, these methods are restricted to inviscid flow.

Several examples of both ‘pressure’ and ‘optimisation’ methods are discussed, and their advantages and limitations considered.
Transonic buffet on a supercritical aerofoil
Authors: Lee B. H. K.
Published: March 2023

The buffet characteristics of a supercritical aerofoil were investigated in the High Reynolds Number Two-Dimensional Test Facility of the National Aeronautical Establishment (NAE). The test was performed quite deep into the buffet régime. The buffet onset boundary was determined from the divergence of the unsteady balance normal force. Steady and unsteady pressure measurements were obtained for shock-induced separation with reattachment as well as fully separated flows. For flow conditions where discrete shock wave oscillations occurred, ensemble-averaging of the unsteady pressures determined the propagation velocity of the pressure wave induced by periodic shock motion. A model of the self-sustained oscillatory shock motion due to shock-boundary layer interaction was formulated. Broad-band cross-correlations of the pressure field determined the downstream convection velocities of the turbulent eddies of separated flows.
Pilot modelling techniques for the analysis of aircraft linear dynamic behaviour
Authors: Innocenti M. , Minciotti R. L.
Published: March 2023

The evaluation of aircraft flying qualities has always required a high level of integration between airplane dynamic response and human operator properties. Today, the linear pilot-aircraft behaviour is a mature technology summarised by the publication of the military specifications MIL-STD-1797.

The present paper outlines the contribution of pilot modelling techniques to such endeavour and their use as a tool in the prediction of aircraft handling qualities characteristics by verifying their output in a Neal-Smith criterion framework. The objective is to complete the understanding of handling qualities in the linear part of the flight envelope (such as tracking) and to initiate work in the large amplitude manoeuvres. The results have produced an interactive computer aided software useful for pilot-in-the-loop analysis.
Separated flow about a wedge
Authors: Mukherjea S. , Bandyopadhyay G.
Published: March 2023

A numerical method, based on the panel technique, has been developed for calculating the time-averaged separated flow about a wedge. The mathematical model, with constant vorticity in the wake, gives an infinite extension of the wake and constant base pressure while incorporation of the dispersion of vorticity in the wake into the mathematical model leads to its finiteness and non-uniform under-pressure. Experimental tests have been conducted in a low speed wind tunnel on models haying different wedge angles. The theoretical and experimental results agree closely for different configurations and specific values of dispersion factors. However, the agreement for base pressure is poor.
Aerodynamic forces on a square section cylinder that is downstream to an identical cylinder
Authors: Luo S. C. , Teng T. C.
Published: March 2023

This paper reports on the measurement of aerodynamic forces that act on a square cylinder which was downstream to an identical cylinder. When the two cylinders were in tandem formation, a critical spacing equal to about four times the side length D of the square cylinder, was found to exist. For L/D < (L/D)cri, where L is the streamwise centre to centre spacing between the two cylinders, the boundary layers which separate from the upstream cylinder reattach onto the downstream cylinder. Only the latter sheds vortices and it is subjected to a thrust rather than a drag force. For LID > (L/D)cri, both cylinders shed vortices and both are subjected to drag forces. When the two cylinders were in staggered formation, due to the presence of various lift generating mechanisms, the lift force that acts on the downstream cylinder can be either positive which points away from the wake centre line of the upstream cylinder or negative which points towards the wake centre line of the upstream cylinder. It was found that in the range 4 ⩽ LID ⩽ 12, an unstable regime exists in that the lift force generated pushes the downstream cylinder away from the upstream cylinder’s wake centre line at small dimensionless transverse spacing (Y/D) where Y is the transverse centre to centre spacing between the two cylinders and reverses its direction only at Y/D > 2. At L/D = 29, the largest streamwise spacing that can be investigated in the present study, the influence that the upstream cylinder has on the aerodynamic forces acting on the downstream cylinder was found to be still fairly appreciable.
Gustave Eiffel - pioneer of experimental aerodynamics
Authors: Black J.
Published: March 2023

Travellers flying into Paris would not connect the famous 100-year-old landmark, the Eiffel Tower, an immense and complex structure of open ironwork, 300 m high, with the aerodynamics of their streamlined modern aeroplane. The unexpected association between the two is Gustave Eiffel — ‘le magicién de fer’ — builder of the Tower in 1889, who pioneered much of the experimental research needed by the designers of the first aeroplanes, in the period from 1903, when he was in his ‘70s, until the time of his death aged 90 in 1923.

Post-Second World War generations of aerodynamicists are also probably unaware that Eiffel was the source of many of the basic results they use, since no modern textbooks refer to his researches of 70 years ago; yet nearly half of his obituary notice in the Times of 29 December 1923, headed ‘M. Eiffel — A Great Engineer’ referred to his aeronautical research using his Tower and his wind-tunnels. In order to appreciate how Eiffel came to embark on his new activities at such a late age we must look briefly at his first career, which established him as one of the most distinguished structural engineers of the 19th century, and the political scandal which brought it to an end.
Sting corrections to zero-lift drag of axisymmetric bodies in transonic flow
Authors: Viswanath P. R. , Rajendra G.
Published: March 2023

Experiments at transonic speeds have been performed on several boat-tailed afterbodies and sting combinations with a view to assessing sting corrections to the measured afterbody drag at transonic speeds. Measurements made included afterbody total drag and base pressure in the Mach number range of 0.6-1.0 and Reynolds number range of 8-9.5 x 106. Correlations of base pressure and boat-tail pressure drag for the sting diameter and flare effects have been proposed using dimensional arguments. The correlations provide quick and reliable estimates for corrections that can be applied to the measured zero-lift drag of axisymmetric bodies with either contoured or conical boat-tailing.
Prediction of the dynamic characteristics of helicopters in constrained flight
Authors: Thomson D. G. , Bradleyt R.
Published: March 2023

In circumstances where a pilot is forced to follow a specified flight path, such as during a landing approach or in nap-of-the-earth conditions, it will be shown that there is an apparent modification of the helicopter's stability characteristics. This effect is identified in helicopter flight data from nap-of-the-earth agility trials where oscillations are observed in the time histories of the pilot's control inputs and the vehicle's response. A technique of predicting the nature of these oscillations using a linearised helicopter mathematical model is developed. The model is inverted to give the response of the unconstrained states in terms of those strongly controlled by the need to remain on a specific flight path. Results are compared with data from flight trials and it is shown that good correlation between the period of the oscillations in the flight data and the predicted values can be obtained.
Effective optimal control of an aircraft engine
Authors: Mahmoud S. , McLean D.
Published: March 2023

The feasibility of using a single effective on-line control law to regulate the dynamic response of a jet engine throughout its flight envelope is of considerable importance. In this paper, a study was made to find such a single effective control law, which was able to regulate the dynamic responses of the linear, and ultimately the non-linear, model, throughout the engine’s entire operating range. This effective control law was obtained from solving a Linear Quadratic Problem (LQP) to obtain an optimal control law, a linear state feedback control.
Air safety regulation and its commercial impact
Authors: Ashford Ronald
Published: March 2023

Safety regulation usually has some direct impact on airline costs. All operators aim to operate safely - some more than others - and one might ask, should safety be left to manufacturers and operators, all of whom have a real vested interest in high standards, including the added spur of potential litigation? However, there is, I believe, a clear wish in the minds of the public, and hence governments, for independent and positive regulation. Major fatal accidents frequently cause a clamour of demands for higher safety, and governments, through their appointed bodies, are expected to act. Airlines broadly accept such pressures but wish to see common and consistent standards applied so that the economic burden is spread equally - preferably internationally.

ICAO requires all aircraft involved in international navigation to conform to ‘a detailed and comprehensive code’, but the detailed provisions and their interpretation may vary from country to country.
Technical Note–The flying wing supersonic transport
Authors: Jones R. T.
Published: March 2023

The flying wing supersonic transport is simply a straight wing of high aspect ratio and of sufficient size to contain passengers comfortably. Such a wing can be steered to different sweep angles and thus adapted to efficient flight over a range of Mach numbers.

The writer demonstrated such a wing by flying models at the First International Congress in the Aeronautical Sciences. The potential advantages of such a flying wing were discussed by G. H. Lee of Handley Page Aircraft at a subsequent Congress. The present paper gives recent studies of flight stability, efficiency and operational problems. It is suggested that by limiting the Mach number to twice current jet speed fuel efficiency approaching that of present day subsonic transports could be achieved. This goal would probably also require the development of variable bypass engines.
An interferometric study of the shock interaction at a compression corner
Authors: Squire L. C. , Bryanston-Cross P. J. , Liu X.
Published: March 2023

This paper presents the results of an interferometric study of the shock/boundary-layer interaction at a compression corner. The boundary layer upstream of the corner is a non-equilibrium state having been disturbed by injection through a porous surface. As well as being relevant to the design of transpiration-cooled surfaces, the results show many similarities to the interaction in an adverse pressure gradient. The changes in the nature of the interaction as the approaching profile is distorted is fully explored and the results should provide a useful test case for computational fluid mechanics. The results are also used to evaluate the accuracy of interferometric techniques.
An investigation of a hovering rotor in ground effect
Authors: Graber A. , Rosen A. , Seginer A.
Published: March 2023

A new free-wake aerodynamic model of a rotor hovering in ground effect is briefly presented. The numerical characteristics of the model are investigated. The convergence between consecutive iterations and convergence with respect to different parameters that define the model, are presented and discussed. The model is then validated by comparing the numerical results with existing experimental data. Very good agreement of the thrust coefficient is obtained, whereas discrepancies in the torque coefficients are discussed. At the end of the paper the capabilities of the model are shown by considering various aspects of the ground effect.
Small satellites and electric propulsion - a review
Authors: Lorenz Ralph
Published: March 2023

In recent years, interest has grown in the use of small satellites for a variety of applications. In certain missions, where propulsion systems are necessary, electric propulsion technology can offer advantages. Small satellite technology and applications are reviewed and some of the features of various types of electric propulsion are discussed: missions where small satellites might use electric propulsion are described.
Validation of transonic turbulent flows past delta wing configurations
Authors: Hilgenstock A.
Published: March 2023

The turbulent flow around a delta wing at incidence is simulated numerically using a finite-volume Navier-Stokes method. The numerical simulation makes use of a simple algebraic turbulence model. The influence of grid refinement is investigated. The more realistic wing-body configuration with round leading edge is used to discuss the influence of the position of the transition line and to compare experimental and numerical data to validate the numerical method. The topological structure of the flow is discussed. An explanation is given for the low particle density area close to the primary vortex as it is visualised by laser light-sheet technique in the experiment. Results for a close coupled delta-wing-canard configuration are discussed.
A tribute to the leading assistant designers of British wartime aeroplanes
Authors: Pugsley Alfred
Published: March 2023

The major achievements of the Royal Air Force during the last war were made possible very largely by three aeroplanes – the Hurricane, the Spitfire, and the Lancaster. They became very well known to the British public at that time, and indeed to the enemy. Less widely known, but nevertheless publicly acknowledged, were their chief designers – S. Camm, R. J. Mitchell and R. Chadwick.

Two other aeroplanes that found a place in the public eye were the Wellington bomber and the Sunderland Flying Boat. A. Gouge, the chief designer of the latter, was hardly noticed, but B. N. Wallis, who contributed most to the design of the Wellington, became a national figure when he moved on to the design of his great bombs.
Bundling telicity, verbal quantification, and perfective aspect: A study on lǝ in Yixing Chinese
Authors: HU XUHUI
Published: March 2023

This paper investigates the properties of a particle, lǝ, in Yixing Chinese that invariably denotes telic reading, obligatorily fronts definite and bare NP objects to the topic position, and imposes past event reading in most situations. It is argued that lǝ is a functional item bearing a quantity feature in the sense of Borer (2005b) and is hence responsible for telicity. Following Partee et al. (1987), Partee (1990), Filip (1997) and Borer (2005b), we propose that lǝ functions as a verbal quantifier, and more specifically, as a verbal universal quantifier, which needs to bind a variable in its quantificational domain. The fronting of definite and bare NPs is compatible with this variable-binding requirement because a trace, and hence a variable, is left as a result of the movement. It is further argued, following the analysis in Lin (2000, 2003, 2007), that lǝ bears a perfective feature. When there is no specific reference time, speech time is taken as default reference time, resulting in the past event reading. lǝ, therefore, bears both an inner aspectual feature and an outer aspectual feature. This paper exhibits how telic items can behave differently across languages and shows the possibility of bundling two temporal features (inner and outer aspectual features) on a single functional item.
Effect of polygenic risk score, family load of schizophrenia and exposome risk score, and their interactions, on the long-term outcome of first-episode psychosis
Authors: Cuesta M. J. , Papiol S. , Ibañez B. , García de Jalón E. , Sánchez-Torres A. M. , Gil-Berrozpe G. J. , Moreno-Izco L. , Zarzuela A. , Fañanás L. , Peralta V. ,   SEGPEPs Group
Published: March 2023

Background

Consistent evidence supports the involvement of genetic and environmental factors, and their interactions, in the etiology of psychosis. First-episode psychosis (FEP) comprises a group of disorders that show great clinical and long-term outcome heterogeneity, and the extent to which genetic, familial and environmental factors account for predicting the long-term outcome in FEP patients remains scarcely known.

Methods

The SEGPEPs is an inception cohort study of 243 first-admission patients with FEP who were followed-up for a mean of 20.9 years. FEP patients were thoroughly evaluated by standardized instruments, with 164 patients providing DNA. Aggregate scores estimated in large populations for polygenic risk score (PRS-Sz), exposome risk score (ERS-Sz) and familial load score for schizophrenia (FLS-Sz) were ascertained. Long-term functioning was assessed by means of the Social and Occupational Functioning Assessment Scale (SOFAS). The relative excess risk due to interaction (RERI) was used as a standard method to estimate the effect of interaction of risk factors.

Results

Our results showed that a high FLS-Sz gave greater explanatory capacity for long-term outcome, followed by the ERS-Sz and then the PRS-Sz. The PRS-Sz did not discriminate significantly between recovered and non-recovered FEP patients in the long term. No significant interaction between the PRS-Sz, ERS-Sz or FLS-Sz regarding the long-term functioning of FEP patients was found.

Conclusions

Our results support an additive model of familial antecedents of schizophrenia, environmental risk factors and polygenic risk factors as contributors to a poor long-term functional outcome for FEP patients.