bluuebunny/crossref_metadata_2025 huggingface dataset:
Vortex flow of downwind sails
Authors: Arredondo-Galeana A. , Babinsky H. , Viola I.M.
Published: February 2023

This paper sets out to investigate the vortex flow of spinnaker yacht sails, which are low-aspect-ratio highly cambered wings used to sail downwind. We tested three model-scale sails with the same sections but different twists over a range of angles of attack in a water tunnel at a Reynolds number of 21 000. We measured the forces with a balance and the velocity field with particle image velocimetry. The sails experience massively separated three-dimensional flow and leading-edge vortices convect at half of the free-stream velocity in a turbulent shear layer. Despite the massive flow separation, the twist of the sail does not change the lift curve slope, in agreement with strip theory. As the angle of attack and the twist vary, flow reattachment might occur in the time-average sense, but this does not necessarily result in a higher lift to drag ratio as the vorticity field is marginally affected. Finally, we investigated the effect of secondary vorticity, vortex stretching and diffusion on the vorticity fluxes. Overall, these results provide new insights into the vortex flow and associated force generation mechanism of wings with massively separated flow.
A direct numerical simulation study on the structures and turbulence–flame interactions of a laboratory-scale lean premixed jet flame in cross-flow
Authors: Cheng Mengzhen , Wang Haiou , Luo Kun , Fan Jianren
Published: February 2023

In the present work, direct numerical simulation of a laboratory-scale lean premixed reacting jet in cross-flow was performed to explore the flow–flame structures and turbulence–flame interactions. A jet of lean premixed ethylene–air mixtures (equivalence ratio

$\phi = 0.6$

) was injected into a hot vitiated cross-flow. Both non-reacting and reacting cases were simulated. It was found that the reacting jet penetrates deeper in the cross-flow with a weaker shear layer compared with the non-reacting one. The wake of the non-reacting and reacting jet is characterized by vertical vortices and recirculation zones, respectively. As for the flame structure of the reacting case, the reaction intensity varies considerably in different flame zones. The heat release rate on the leeward side is higher than that on the windward side, but lower than that of the corresponding laminar flame. The analysis of the turbulence–flame interactions of the reacting case showed that the large local Damköhler number (

$Da$

) related to reaction-induced dilatations results in an increased tendency of the scalar gradient to align with the most extensive strain rate, which is more evident in the regions with high heat release rate on the leeward side. Negative dilatation regions with positive tangential strain rate and negative normal strain rate are observed on the windward side. High positive dilatations appear on the flame front of the leeward side. The tangential strain rate is negatively correlated with the normal strain rate and curvature. Regions with a high local

$Da$

on the windward side correspond with high positive curvature regions.
Reynolds number effects on the prediction
of mean flow data for adiabatic 2-D compressible
boundary layers
Authors: Motallebi F.
Published: February 2023

The paper presents a method for the prediction of mean
flow data (i.e. skin friction, velocity profile and
shape parameter) for adiabatic two-dimensional
compressible turbulent boundary layers at zero
pressure gradient. The transformed law of the wall,
law of the wake, the van Driest model for the
complete inner region and a correlation between the
Reynolds number based on the boundary layer integral
length scale (ReΔ*.) and the Reynolds
number based on the boundary layer momentum
thickness (Reθw) were used to predict the
mean flow quantities. The results for skin friction
coefficient show good agreement with a number of
existing theories including the van Driest II and
the Huang et al. Comparison with a
large number of experimental data suggests that at
least for transonic and supersonic flows, the
velocity profile as described by van Driest and
Coles is Reynolds number dependent and should not be
presumed universal. Extra information or perhaps a
better physical approach to the formulation of the
mean structure of compressible turbulent boundary
layers even in zero pressure gradient and adiabatic
condition, is required in order to achieve complete
(physical and mathematical) convergence when it is
applied in any prediction methods.
Reliability, maintainability and
development cost implications of variable camber
wings
Authors: Fielding J. P. , Vaziry-Zanjany M. A. F.
Published: February 2023

A computer assisted conceptual aircraft design
methodology (CACAD) has been developed to size
turbofan powered transport aircraft. New modules for
predicting the maintenance costs of each airframe
system and subsection of structure, were developed
and incorporated into CACAD.

Many aspects of variable camber wing technology (VCW)
were modelled. These included different types of
drag saving due to chordwise, as well as spanwise
camber variation. Models were also derived for mass,
maintenance cost, and extra development cost
increments for wing trailing edge devices, flight
control, and hydraulic systems. These were
incorporated into CACAD, and then a
multidisciplinary trade-off study resulted in
predicted savings of up to 3·5% in direct operating
cost (DOC). The technology was evaluated for DOC
improvement against a number of existing, future,
and derivative aircraft, under different sensitivity
conditions. Reliability, maintainability, and
development (R, M&D) predictions were shown to
be decisive in determining the feasibility of VCW
technology. The study showed that long range, low to
medium capacity, derivative aircraft are the most
suitable applications for VCW technology.
Crack growth characteristics of integrally
machined stringer–skin panels
Authors: Young J. B. , Ashfaq Sheikh M.
Published: February 2023

The variation of the stress intensity factor (SIF) for
cracks growing in integrally machined stiffened skin
panels have been studied in an isotropic material.
The stringer-skin panel has been modelled using the
Nastran finite element system with allowance for
crack tip singularity by use of crack tip elements.
To allow for variations in stringer and skin
geometry, three stiffness ratios (stringer
stiffness-skin stiffness) were investigated.

The stress intensity factors have been converted into
nondimensionalised values of stress intensity factor
coefficients (K1/K0). A damage
tolerant and residual strength analysis has been
carried out using an in-house computer program.
Results indicate very little difference for the
different stiffness ratios examined.
Aerodynamic characteristics of low-drag
bicycle wheels
Authors: Greenwell D. I. , Wood N. J. , L. Bridge E. K. , Addy R. J.
Published: February 2023

A number of modern “aerodynamic” bicycle wheels were
tested at full scale speeds in a windtunnel. The
effects of wheel geometry, rotational speed and
cross winds on drag force, side force and yawing
moment were investigated.

Compared with a conventional spoked wheel, all the
“aerodynamic” wheels were found to give similar
improvements in drag of approximately 25%. In cross
wind conditions, aerodynamic characteristics were
strongly dependent on wheel geometry, but
essentially independent of wheel rotational
speed.
A note on the interpretation of mini-tuft
photographs
Authors: Mabey D. G. , Welsh B. L. , Pyne C. R.
Published: February 2023

Although mini-tufts are considered generally to show
the surface flow direction on windswept surfaces,
there is some uncertainty about their correct
interpretation, particularly as three-dimensional
flows approach separation. This note provides some
guidance on this controversial question, based on
experience with mini-tufts on wings, fins and
canards in the DRA 13 ft x 9 ft low speed
wind-tunnel at Bedford.

An illustration of the value of the technique is given.
Mini-tuft photographs are used to identify the
trailing edge condition which relates to the
classification of the steady and fluctuation
pressure distributions observed a swept wing with a
conical, separated flow.
Criteria for location of vortex breakdown
over delta wings
Authors: Gursul I.
Published: February 2023

Vortex breakdown phenomenon remains a challenging
aspect of the flow over delta wings at high angle of
attack. The observations of vortex breakdown and
related interpretations for vortex tube experiments
and delta wings are summarised in several review
articles. The theoretical models of the phenomena
are described in detail in References 1, 2, 3 and 7.
These theoretical models are not complete enough to
predict breakdown location over delta wings. The
purpose of this note is to review several existing
criteria and correlations for vortex breakdown over
delta wings using a large database. The earliest
criteria for delta wings was suggested by Lambourne
and Bryer.
Separation control on highly-swept wings
with fixed or variable camber
Authors: Ashill P. R. , Riddle G. L. , Stanley M. J.
Published: February 2023

This paper describes an experimental investigation into
the effect of miniature vortex generators (VGs) on
the longitudinal aerodynamic characteristics of a
highly-swept wing with drooped leading edges. The
experiments were performed in a low-speed windtunnel
on a wing of the same delta planform as that used in
a previous study. The latter wing was of fixed
camber, while the subject of the present study was a
wing with three different leading edge droop angles.
The maximum reduction in drag due to the VGs was
found to be about half that for the fixed-camber
wing. This is reconciled with the different
behaviour of the flow on the upper surface for the
two types of wing. Without control, the drag of the
variable-droop wings is much lower than that of the
fixed-camber wing. As a result, with control, the
variable droop wings have lower drag than that of
the fixed-camber wing. Compared to that of the
variable-droop wings without control, the
fixed-camber wing, with control, has lower
lift-dependent drag for lift coefficients between
0·4 and 0·7. However, at higher lift coefficients,
the reverse applies.
Asymmetric vibration of viscoelastically
damped multilayered conical shell
Authors: Khatri K. N.
Published: February 2023

Asymmetric vibration of multilayered conical shell with
core layers of viscoelastic material are
investigated in this paper. The analysis presented
herein considers bending, extension in plane shear
and transverse shear deformations in each of the
layers, and also includes rotary, longitudinal
translatory and transverse inertias. Appropriate
trigonometric series are used as solution functions
in the Galerkin method to reduce the governing
equations to a set of matrix equations. The
corresponding principle of linear viscoelasticity
for harmonic motion is used for evaluating the
damping effectiveness of shells with elastic and
viscoelastic layers. A computer program has been
developed for determining the resonance frequencies
and associated system loss factors for various modes
of families of asymmetric vibration of a general
multilayered conical shell consisting of an
arbitrary number of specially orthotropic material
layers. Variation of resonance frequencies and the
associated system loss factors with total thickness
parameter and circumferential modal number for
three, five and seven layered conical shells, with
three sets of classical end conditions: simply
supported at both ends, clamped-clamped and
free-free, which can be of some use to designers,
are been reported.
Structural dynamics-CFD interaction for
computation of vertical tail buffet
Authors: Kandil O. A. , Massey S. J. , Sheta E. F.
Published: February 2023

The multidisciplinary problem of tail buffeting is
solved using three sets of equations. The first set
is the unsteady, compressible, full Navier-Stokes
equations which are used for obtaining the flowfield
vector and the aerodynamic loads. The second set is
the coupled aeroelastic equations which are used for
obtaining the bending and torsional deflections of
the tail. The third set is the grid-displacement
equations which are used for updating the grid
coordinates due to the tail deflections. For the
computational applications, a sharp-edged delta wing
of aspect ratio one and a rectangular vertical tail
of aspect ratio one placed in the plane of geometric
symmetry behind the wing are considered. The
configuration is pitched at a critical angle of
attack (α = 38°) which produces asymmetric,
vortex-breakdown flow from the delta wing primary
vortices. The results show the effects of coupled
and uncoupled bending-torsional responses and the
effects of Reynolds number.
Aircraft dynamics optimisation via linear
matrix inequalities
Authors: Mengali G.
Published: February 2023

This paper deals with the problem of determining an
optimal controller which minimises the
norm of a given aircraft
while guaranteeing that an upper limit of its
norm is not exceeded. The
problem is tackled by means of a linear matrix
inequality formulation, which allows one to
constrain the eigenvalues of the model to within a
fixed region of the complex plane. Key features of
the method are the possibility of simultaneously

1. keeping the maximum value of the input
demand under control

2. taking flying quality requirements into
account

3. assuring a minimum level of system
robustness against uncertainties of the model.

The approach is simple to handle and is well suited to
the design of aircraft stability augmentation
systems. A discussion of two case studies
demonstrates the effectiveness of the procedure.
On the start condition of a second-throat
ejector-diffuser
Authors: Wang J. J. , Chen F.
Published: February 2023

The start condition of a second-throat ejector-diffuser
(STED) system has been studied by solving the
axisymmetric Navier-Stokes equations with a high
order conservative supra-characteristics method
(CSCM). According to the conventional concept, when
a STED is started, the flow passing through the
second-throat contraction should be supersonic so
that the normal shock swallowing condition applying
for a supersonic windtunnel holds. The present
numerical results, however, suggest that a STED can
be started with a normal shock forming ahead of the
second-throat contraction because the high speed
flow in the region close to the wall of the diffuser
serves to release the mass blocked by the normal
shock, leading to a decrease in chamber pressure as
well as the start of the system. This not only
contradicts the conventional concept of the start of
a STED, but also provides an explanation for the
experimental discrepancy between the start
conditions of a STED and a supersonic
windtunnel.
Characterisation of sandpaper roughness
under a turbulent incompressible boundary
layer
Authors: Gibbings J. C. , Al-Shukri S. M.
Published: February 2023

The work reported here extends the work of Nikuradse on
the categorisation of surface roughness. Nikuradse’s
work considered pipe flow, whilst in this paper
boundary layer flow is investigated. Important and
fundamental differences between these two types of
flow are shown. An experiment upon turbulent
boundary layers over sandpaper-type roughnesses
enabled a fluid-mechanic categorisation of these
surfaces to be obtained for this flow. This is
compared with some shape and size categorisations of
the roughnesses from detailed measurements.
Multi-sensor data fusion for helicopter
guidance using neuro-fuzzy estimation
algorithms
Authors: Doyle R. S. , Harris C. J.
Published: February 2023

The purpose of this paper is to describe an approach
which performs data fusion on the output of
multiple, spatially separate, sensors engaged in the
real time tracking of obstacles in a helicopter's
environment. The generated information can be used
either as a flight director aid or as feedback
required by an automatic collision avoidance system.
Obstacle track estimation has been commonly carried
out using the Kalman filter (KF) for linear
estimation, or the extended Kalman filter (EKF) for
use on nonlinear problems. However, certain
assumptions made in the derivation of the EKF
algorithms render it sub-optimal for aerial obstacle
track estimation. Additionally, the EKF has problems
with initialisation and divergence (stability) for
many non-linear processes.

Research at the University of Southampton has
highlighted a link between fuzzy networks and
associative memory neural networks. This link is
important as it allows new learning rules to be
developed for training fuzzy rules, and learning
convergence to be proved. This paper explores
methods of fusion of estimates using neuro-fuzzy
models, and addresses some of the weakness of the
Kalman filter approximation introduced by the
assumptions made in its derivation.
Aerodynamic technology — the role of
aerodynamic technology in the design and development
of modern combat aircraft
Authors: McMichael T. , McKay K. , Walker M.J. , Fielding C. , Lockley G. , Curtis P. , Probert B. , Lee C. S. , Moretti G.
Published: February 2023

This paper examines the changing role aerodynamic
technology plays in the design and development of
modern combat aircraft. It reviews several aspects
of aerodynamics which contribute to aircraft
performance and handling characteristics. It
considers the importance of a range of technologies,
the contribution each makes to the final integrated
solution and comments on the compromises necessary
through the design cycle to optimise the overall
weapon system, sometimes to the cost of one of the
component technologies. The technologies discussed
are in no way exhaustive but attempt to encapsulate
the breadth of the subject, to illustrate its
diversity and to point the way for the future
development if aerodynamic technology is to continue
to make an important contribution to the design of
combat aircraft.

Each of the component technologies are discussed in
terms of the contribution it makes, the tools and
techniques used to predict, analyse and interpret
the technology contribution, and the requirements
for the direction of the development of the
technology for the future.

Before considering the technologies themselves it is
important to understand the environment in which
they will be used, which increasingly conditions the
manner in which they are employed and suggests the
direction for their development.

This paper begins, therefore, by briefly reviewing the
changes to the environment in which the fighter
pilot operates and the manner by which his
requirements, and therefore the specification of the
aircraft, are defined before going on to look at the
overall contribution each technology makes in the
design process.
Buffeting tests in a cryogenic
windtunnel
Authors: Mabey D. G. , Boyden R. P. , Johnson W. G.
Published: February 2023

Measurements of wing buffeting, using root strain
gauges, were made in the Nasa Langley 0-3 m
cryogenic windtunnel to refine techniques which will
be used in larger cryogenic facilities such as the
United States National Transonic Facility (NTF) and
the European Transonic Windtunnel (ETW). The
questions addressed included the relative importance
variations in frequency parameter and Reynolds
number, the choice of model material (considering
both stiffness and damping) and the effects of
static aeroelastic distortion.

The main series of tests was made on three half models
of slender 65° delta wings with a sharp leading
edge. The three delta wings had the same planform
but widely differing bending stiffnesses and
frequencies (obtained by varying both the material
and the thickness of the wings). It was known that
the steady flow on this configuration would be
insensitive to variations in Reynolds number. On
this wing at vortex breakdown the spectrum of the
unsteady excitation is unusual, having a sharp peak
at particular frequency parameter.

Additional tests were made on one unswept half-wing of
aspect ratio 1·5 with an NPL 9510 aerofoil section,
known to be sensitive to variations in Reynolds
number at transonic speeds. The test Mach numbers
were M = 0·21 and 0·35 for the delta wings and to M
= 0·30 for the unswept wing. On this wing the
unsteady excitation spectrum is fairly flat (as on
most wings). Hence correct representation of the
frequency parameter is not particularly
important.
Effect of spherical roughness elements upon
transition of a 3-D boundary layer
Authors: M. Ö. Çarpinlioglu  , Ö. T. Göksel
Published: February 2023

The influence of isolated spherical roughness elements
upon the transition of a three-dimensional boundary
layer on a swept flat plate is discussed in this
paper. Perturbations induced by the roughness are
found to be more effective on the start of
transition rather than the crossflow of the laminar
undisturbed boundary layer at the roughness
location.
Photosynthesis rate, radiation and water use efficiencies of irrigated potato in a semi-arid climate using Eddy covariance techniques
Authors: Machakaire A. T. B. , Steyn J. M. , Franke A. C.
Published: February 2023

Understanding the photosynthetic behaviour, radiation use efficiency (RUE) and water use efficiency (WUE) of potatoes in response to diurnal and seasonal fluctuations in weather, is important for optimizing growth and production. The net ecosystem exchange (NEE) of carbon dioxide (CO2), is a parameter used to measure the balance between gross CO2assimilation (also referred to as gross primary production (GPP)) and ecosystem respiration (Reco). The objectives of this study were (i) to quantify the NEE of potato grown in two contrasting agro-ecologies and partition NEE intoRecoand GPP; (ii) to describe seasonal patterns in daily photosynthesis, RUE and WUE in potato; and (iii) to analyse the variability in photosynthesis rate, RUE and WUE as affected by weather and crop growth stage. We measured CO2and water vapour fluxes using eddy covariance techniques in potato fields in two production regions of South Africa. The winter crop had higher mean RUE and WUE values, whereas the summer crop absorbed more CO2. RUE had a negative relationship with incident radiation. To optimize dry matter production, WUE and RUE, potato crops must be well established and develop a full canopy early during the season. Maintaining the crop for a longer period in the field has yield benefits, although they appear to decline over time due to reduced efficiencies as the crop matures. The RUE observed over the growing period in the present study was high, relative to findings by other field studies, despite relatively warm growing conditions that were likely sub-optimal for potato.
State of the art in assisted reproductive technologies for patients with advanced maternal age
Authors: Yurchuk Taisiia , Petrushko Marina , Fuller Barry
Published: February 2023

According to the World Health Organization, the female reproductive age lasts up to 49 years, but problems with the realization of women’s reproductive rights may arise much earlier. Significant numbers of factors affect the state of reproductive health: socioeconomic, ecological, lifestyle features, the level of medical literacy, and the state of the organization and medical care quality. Among the reasons for fertility decline in advanced reproductive age are the loss of cellular receptors for gonadotropins, an increase in the threshold of sensitivity of the hypothalamic-pituitary system to the action of hormones and their metabolites, and many others. Furthermore, negative changes accumulate in the oocyte genome, reducing the possibility of fertilization, normal development and implantation of the embryo and healthy offspring birth. Another theory of ageing causing changes in oocytes is the mitochondrial free radical theory of ageing. Taking into account all these age-related changes in gametogenesis, this review considers modern technologies aimed at the preservation and realization of female fertility. Among the existing approaches, two main ones can be distinguished: methods allowing the preservation of reproductive cells at a younger age using ART intervention and cryobanking, as well as methods aimed at improving the basic functional state of advanced-age women’s oocytes and embryos.
SMITH AT 300: ADAM SMITH ON EDINBURGH AND GLASGOW
Authors: Smith Craig
Published: February 2023

It is a difficult task to narrow down a favorite passage from a body of work as rich as that of Adam Smith. One of the things that has always amused me about Smith is his use of Scottish examples to make universal points. In one of these he launches himself into the long-running rivalry between Scotland’s two major cities: Edinburgh and Glasgow. Smith lived for a time in both cities and worked on what would become the Wealth of Nations in what were then, as now, two very different cities. In The Wealth of Nations he makes use of this to develop a classic example of Smithian social theory.
The effects of farming system and soil management on floristic diversity in sloping olive groves
Authors: Jiménez María Noelia , Castro-Rodríguez Juan , Navarro Francisco Bruno
Published: February 2023

The effects of the farming system (conventional-organic-abandoned) and soil management (native cover crop vs tillage) on vascular plant species were analyzed in sloping olive groves (>20%) in 20 different locations in Andalusia, SE Spain. The soil management techniques included Organic Tillage (OT), Organic Cover Crops (OC), Conventional Tillage (CT), Conventional Non-Tillage (CNT), Abandoned Cover Crops (AC) and Abandoned Woody (AW). Data for the vascular plant species were recorded through three line transects of 30 m with a bar perpendicularly touching every 1 m of the measuring tape. Environmental variables were also recorded at plot level to assess their influence. Dependent variables, such as species abundance, richness and diversity indexes were studied using univariate analysis (one-way ANOVA, Kruskal–Wallis test) while multivariate statistics (ANOSIM, SIMPER, DCA) were used for analyzing the data matrices. We found that the different combinations of farming system and soil management affect biological diversity in terms of individual abundance, plant cover, species richness and diversity, species and family composition. Life forms and species distribution patterns are also affected. The main environmental variables affecting the plant taxa were those related with soil and climate characteristics, slope, olive age and intensive land uses at landscape level, including the percentage of artificial surfaces. The lowest levels of biodiversity (e.g., species richness) were found in the tilled olive groves (CT = 8.1 sp. ± 2.2, OT = 10.0 sp. ± 5.4). Surprisingly, the organic tilled groves (OT) were very poor in species compared to those with native plant cover (OC = 27.9 sp. ± 3.0). The latter, however, showed similar species richness to the abandoned olive groves (AC = 21.2 sp. ± 3.7, AW = 27.2 sp. ± 3.0). Possible solutions for increasingly uncompetitive sloping olive groves include conversion to organic with native plant cover or abandonment for rewilding.
Women, Revolution, and Backlash: Igniting Feminist Mobilization in Sudan
Authors: Tønnessen Liv , Al-Nagar Samia
Published: February 2023

Women were at the forefront of the popular uprising that overthrew Sudan’s dictator, Omar al-Bashir, in 2019 (Al-Nagar and Tønnessen 2021). In the aftermath of the uprising, different forms of feminist mobilization emerged. Based on interviews conducted in Sudan in early 2022, we argue that this feminist mobilization was sparked by the backlash facing women during and after what is popularly known as the “December revolution.”1
From Yewwu Yewwi to #FreeSenegal: Class, Gender and Generational Dynamics of Radical Feminist Activism in Senegal
Authors: Dieng Rama Salla
Published: February 2023

Feminists protesting gender-based violence and state violence have been instrumental to contesting the status quo and the shifting discourses, modes of organizing, and registers of protest in Senegal. Some 40 years after the emergence of Yewwu Yewwi, a major feminist movement, Senegalese feminists have returned to radical feminist organizing, despite increasing anti-gender backlash. In this essay, I draw on interviews with feminist activists and politicians between 2013 and 2022 to analyze the March 2021 protests in Senegal in light of previous protests. I argue that the intertwined dynamics of class, gender, and generation are critical to understanding the protests. I do this following the example of some feminist academics who have used intersectionality as a method, theory, and research agenda (Collins and Bilge 2016; Mohammed 2022). Innovations in protest strategies have allowed activists to overcome generational and ideological divides between feminist and women’s rights organizations, as well as within feminist movements, and to resist strategic alliances between patriarchal and political powers.
Die Eidgenössische Kommission für Qualitätssicherung in der medizinischen Begutachtung (EKQMB)
Authors: Schleifer Roman , Liebrenz Michael
Published: February 2023

Zusammenfassung. Zum 1. Januar 2022 wurde vom Bundesrat die Eidgenössische Kommission für Qualitätssicherung in der medizinischen Begutachtung geschaffen, welche die Zulassung als Gutachterstelle, das Verfahren zur Gutachtenerstellung und die Ergebnisse der medizinischen Gutachten überwachen und öffentliche Empfehlungen aussprechen soll. Der vorliegende Artikel beschreibt die Zusammensetzung und die Aufgaben der Kommission. Zusätzlich werden die bestehenden Qualitätssicherungsmassnahmen und mögliche neue Wege in diesem dargestellt.
Reducing Literature Screening Workload With Machine Learning
Authors: Burgard Tanja , Bittermann André
Published: February 2023

Abstract. In our era of accelerated accumulation of knowledge, the manual screening of literature for eligibility is increasingly becoming too labor-intensive for summarizing the current state of knowledge in a timely manner. Recent advances in machine learning and natural language processing promise to reduce the screening workload by automatically detecting unseen references with a high probability of inclusion. As a variety of tools have been developed, the current review provides an overview of their characteristics and performance. A systematic search in various databases yielded 488 eligible reports, revealing 15 tools for screening automation that differed in methodology, features, and accessibility. For the review on the performance of screening tools, 21 studies could be included. In comparison to sampling records randomly, active screening with prioritization approximately halves the screening workload. However, a comparison of tools under equal or at least similar conditions is needed to derive clear recommendations.
Meta-Analytic Structural Equation Modeling With Fallible Measurements
Authors: Gnambs Timo , Sengewald Marie-Ann
Published: February 2023

Abstract. Meta-analytic structural equation modeling (MASEM) combines the strengths of meta-analysis with the flexibility of path models to address multivariate research questions using summary statistics. Because many research questions refer to latent constructs, measurement error can distort effect estimates in MASEMs if the unreliability of study variables is not properly acknowledged. Therefore, a comprehensive Monte Carlo simulation evaluated the impact of measurement error on MASEM results for different mediation models. These analyses showed that point estimates in MASEM were distorted by up to a third of the true effect, while confidence intervals exhibited undercoverage that were less than 10% in some situations. However, the use of adjustments for attenuation facilitated recovering largely undistorted point and interval estimates in MASEMs. These findings emphasize that MASEMs with fallible measurements can often yield highly distorted results. We encourage applied researchers to regularly adopt adjustment methods that account for attenuation in MASEMs.
Modeling Post‐Wildfire Hydrologic Response: Review and Future Directions for Applications of Physically Based Distributed Simulation
Authors: Ebel Brian A. , Shephard Zachary M. , Walvoord Michelle A. , Murphy Sheila F. , Partridge Trevor F. , Perkins Kim S.
Published: February 2023

Wildfire is a growing concern as climate shifts. The hydrologic effects of wildfire, which include elevated hazards and changes in water quantity and quality, are increasingly assessed using numerical models. Post‐wildfire application of physically based distributed models provides unique insight into the underlying processes that affect water resources after wildfire. This work reviews and synthesizes post‐wildfire applications of physically based distributed models by examining the scales and geographic/ecohydrologic distribution of model applications, hydrologic response process representation, model parameterization, and model performance metrics. Highlighted gaps and opportunities for advancing physically based distributed hydrologic response modeling after wildfire include the following: (a) applying models in under‐represented geographic (S. America, Africa, Asia) and ecohydrologic regions (arid or dry subhumid climates), (b) incorporating all four major streamflow generation mechanisms (infiltration excess, saturation excess, subsurface storm flow, and groundwater flow), (c) representing integrated vadose zone and saturated zone processes to better capture subsurface streamflow generation, (d) building new remotely sensed model parameterization methods for precipitation interception, infiltration, and overland flow that account for burn severity and recovery, (e) incorporating distributed state variables (e.g., soil moisture, groundwater levels) in model performance assessment, (f) designing model intercomparison studies, including field datasets specifically for post‐wildfire model development and validation, (g) linking mechanistic vegetation regrowth models with hydrologic models to improve simulation of process shifts as ecosystems recover, and (h) creating a new community modeling framework to integrate modeling advances across the wildfire science community.
Remarkable Changes in the Dominant Modes of North Pacific Sea Surface Temperature
Authors: Werb Benjamin E. , Rudnick Daniel L.
Published: February 2023

The analysis revisits the calculation of the empirical orthogonal functions (EOFs) and principal components (PCs) of sea surface temperature (SST) in the North Pacific from 1950 to 2021. The first EOF and PC of SST has proven to be such a useful metric of variability in the North Pacific that it is called the Pacific Decadal Oscillation (PDO). We find that the period of persistent marine heatwaves beginning in 2014 caused a fundamental change to the first EOF and PC of SST (calculated using data from 1950 to 2021) as compared to the established PDO spatial pattern (calculated using data from 1950 to 1993). The second EOF of SST has also changed during this period, both in spatial pattern and in the amount of variance explained. A conclusion is that the PDO and other EOF based metrics may not be as useful in the future as climate continues to change.
Persistence of Cold Wedges in the Somali Current System
Authors: Hormann Verena , Centurioni Luca R. , Paluszkiewicz Theresa
Published: February 2023

The Somali Current system in the western Arabian Sea reverses seasonally with the South Asian Monsoon and is associated with localized upwelling cells or cold wedges during the summer southwest monsoon. Drifter trajectories in boreal summer and fall 2014 provide rare observational evidence that the northward Somali Current and associated cold wedges can persist into the boreal fall intermonsoon period. The near‐surface circulation and sea surface temperatures further suggest that the wedge‐like surface signatures may intermittently be capped and then reappear at a later time. Our observations show that the northward Somali Current system rapidly decayed within 1 week after the onset of the winter northeast monsoon and the arrival of a cyclonic eddy at the coast in early November 2014. This eddy may not only have affected regional ocean‐atmosphere interactions but also biogeochemical processes and the marine ecosystem through the transport of water properties and locally induced upwelling.
Interannual Variability of Regional Hadley Circulation and El Niño Interaction
Authors: Li Yadi , Xie Shang‐Ping , Lian Tao , Zhang Gan , Feng Juan , Ma Jing , Peng Qihua , Wang Wenzhu , Hou Yurong , Li Xichen
Published: February 2023

El Niño‐Southern Oscillation (ENSO) triggers variations of the global Hadley circulation (HC), while the latter may potentially feedback to ENSO events. Previous studies mainly investigated the interactions between ENSO and the global zonal‐mean HC. Here, we present a regional perspective of HC variability by introducing zonal variations. Results show that El Niño intensifies the regional HC over the central‐eastern Pacific, while weakening the regional HC over both the Indo‐Pacific warm pool and the tropical Atlantic. The background seasonal cycle modulates the equatorial‐asymmetric component of HC, with an anticlockwise (clockwise) asymmetric circulation over the central equatorial Pacific before (after) El Niño peaks. Remarkably, the asymmetric HC in boreal spring leads ENSO with a lead correlation of up to 0.68, mediated by the wind‐evaporation‐sea surface temperature (SST) feedback and other atmosphere‐ocean dynamics. The antecedent HC anomaly may contribute to ENSO predictability.
Agyrotropic Electron Distributions in the Terrestrial Foreshock Transients
Authors: Gao C.‐H. , Tang B.‐B. , Guo X.‐C. , Li W. Y. , Khotyaintsev Y. V. , Graham D. B. , Turner D. L. , Yang Z. W. , Wang C.
Published: February 2023

Agyrotropic electron distributions are frequently taken as an indicator of electron diffusion regions of magnetic reconnection. However, they have also been found at electron‐scale boundaries of the non‐reconnecting magnetopause and are generated by the electron finite gyroradius effect. Here, we present magnetospheric multiscale observations of agyrotropic electron distributions in the foreshock region. These distributions are generated by the electron finite gyroradius effect after magnetic curvature scattering at a thin electron‐scale boundary. Meanwhile, the signatures of magnetic reconnection are absent at this boundary. The test‐particle simulation is adopted to verify the generation of the agyrotropic electron distributions by assuming one‐dimensional magnetic geometry. These observations suggest that agyrotropic electron distributions can be more widely formed at electron‐scale boundaries in space plasma environment.
TRICE‐2 Rocket Observations in the Low‐Altitude Cusp: Boundaries and Comparisons With Models
Authors: Petrinec S. M. , Kletzing C. A. , Bounds S. R. , Fuselier S. A. , Trattner K. J. , Sawyer R. P.
Published: February 2023

The launch of the Twin Rockets to Investigate Cusp Electrodynamics‐2 (TRICE‐2) took place on the morning of 08 December 2018. The two rockets of this campaign each sampled the low‐altitude Northern Hemisphere cusp region at approximately the apex of each rocket's trajectory (1,042 and 757 km for the High flyer and Low flyer, respectively). Ion and electron electrostatic analyzers (ESAs) on board each rocket measured in situ particle populations throughout the flights. Energy‐flux spectrograms of ions and electrons from each ESA clearly show the passage of each rocket through the cusp region. This work examines the locations of these entrance/exit points in relation to cusp models as provided in and compiled from the published literature, along with a discussion of model variables that have been optimized to best fit the cusp region boundary sampling locations by TRICE‐2. The results of this study set the stage for understanding the upcoming NASA Small Explorer Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites orbital plane intersections with (i.e., “trajectory cuts” through) the cusp region.
Clinical and biological markers predictive of treatment response associated with metastatic pancreatic adenocarcinoma
Authors: Dayimu Alimu , Di Lisio Lorena , Anand Shubha , Roca-Carreras Isart , Qian Wendi , Al-Mohammad Abdulrahman , Basu Bristi , Valle Juan W. , Jodrell Duncan , Demiris Nikos , Corrie Pippa
Published: February 2023

Background

Chemotherapy for metastatic pancreatic adenocarcinoma (PDAC) offers limited benefits, but survival outcomes vary. Reliable predictive response biomarkers to guide patient management are lacking.

Methods

Patient performance status, tumour burden (determined by the presence or absence of liver metastases), plasma protein biomarkers (CA19-9, albumin, C-reactive protein and neutrophils) and circulating tumour DNA (ctDNA) were assessed in 146 patients with metastatic PDAC prior to starting either concomitant or sequential nab-paclitaxel + gemcitabine chemotherapy in the SIEGE randomised prospective clinical trial, as well as during the first 8 weeks of treatment. Correlations were made with objective response, death within 1 year and overall survival (OS).

Results

Initial poor patient performance status, presence of liver metastases and detectable mutKRAS ctDNA all correlated with worse OS after adjusting for the different biomarkers of interest. Objective response at 8 weeks also correlated with OS (P = 0.026). Plasma biomarkers measured during treatment and prior to the first response assessment identified ≥10% decrease in albumin at 4 weeks predicted for worse OS (HR 4.75, 95% CI 1.43–16.94, P = 0.012), while any association of longitudinal evaluation of mutKRAS ctDNA with OS was unclear (β = 0.024, P = 0.057).

Conclusions

Readily measurable patient variables can aid the prediction of outcomes from combination chemotherapy used to treat metastatic PDAC. The role of mutKRAS ctDNA as a tool to guide treatment warrants further exploration.

Clinical trial registration

ISRCTN71070888; ClinialTrials.gov (NCT03529175).
The p53 endoplasmic reticulum stress-response pathway evolved in humans but not in mice via PERK-regulated p53 mRNA structures
Authors: Fusée Leila , Salomao Norman , Ponnuswamy Anand , Wang Lixiao , López Ignacio , Chen Sa , Gu Xiaolian , Polyzoidis Stavros , Vadivel Gnanasundram Sivakumar , Fahraeus Robin
Published: February 2023

Cellular stress conditions activate p53-dependent pathways to counteract the inflicted damage. To achieve the required functional diversity, p53 is subjected to numerous post-translational modifications and the expression of isoforms. Little is yet known how p53 has evolved to respond to different stress pathways. The p53 isoform p53/47 (p47 or ΔNp53) is linked to aging and neural degeneration and is expressed in human cells via an alternative cap-independent translation initiation from the 2nd in-frame AUG at codon 40 (+118) during endoplasmic reticulum (ER) stress. Despite an AUG codon in the same location, the mouse p53 mRNA does not express the corresponding isoform in either human or mouse-derived cells. High-throughput in-cell RNA structure probing shows that p47 expression is attributed to PERK kinase-dependent structural alterations in the human p53 mRNA, independently of eIF2α. These structural changes do not take place in murine p53 mRNA. Surprisingly, PERK response elements required for the p47 expression are located downstream of the 2nd AUG. The data show that the human p53 mRNA has evolved to respond to PERK-mediated regulation of mRNA structures in order to control p47 expression. The findings highlight how p53 mRNA co-evolved with the function of the encoded protein to specify p53-activities under different cellular conditions.
Microbiota-derived 3-IAA influences chemotherapy efficacy in pancreatic cancer
Authors: Tintelnot Joseph , Xu Yang , Lesker Till R. , Schönlein Martin , Konczalla Leonie , Giannou Anastasios D. , Pelczar Penelope , Kylies Dominik , Puelles Victor G. , Bielecka Agata A. , Peschka Manuela , Cortesi Filippo , Riecken Kristoffer , Jung Maximilian , Amend Lena , Bröring Tobias S. , Trajkovic-Arsic Marija , Siveke Jens T. , Renné Thomas , Zhang Danmei , Boeck Stefan , Strowig Till , Uzunoglu Faik G. , Güngör Cenap , Stein Alexander , Izbicki Jakob R. , Bokemeyer Carsten , Sinn Marianne , Kimmelman Alec C. , Huber Samuel , Gagliani Nicola
Published: February 2023

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second most deadly cancer by 2040, owing to the high incidence of metastatic disease and limited responses to treatment1,2. Less than half of all patients respond to the primary treatment for PDAC, chemotherapy3,4, and genetic alterations alone cannot explain this5. Diet is an environmental factor that can influence the response to therapies, but its role in PDAC is unclear. Here, using shotgun metagenomic sequencing and metabolomic screening, we show that the microbiota-derived tryptophan metabolite indole-3-acetic acid (3-IAA) is enriched in patients who respond to treatment. Faecal microbiota transplantation, short-term dietary manipulation of tryptophan and oral 3-IAA administration increase the efficacy of chemotherapy in humanized gnotobiotic mouse models of PDAC. Using a combination of loss- and gain-of-function experiments, we show that the efficacy of 3-IAA and chemotherapy is licensed by neutrophil-derived myeloperoxidase. Myeloperoxidase oxidizes 3-IAA, which in combination with chemotherapy induces a downregulation of the reactive oxygen species (ROS)-degrading enzymes glutathione peroxidase 3 and glutathione peroxidase 7. All of this results in the accumulation of ROS and the downregulation of autophagy in cancer cells, which compromises their metabolic fitness and, ultimately, their proliferation. In humans, we observed a significant correlation between the levels of 3-IAA and the efficacy of therapy in two independent PDAC cohorts. In summary, we identify a microbiota-derived metabolite that has clinical implications in the treatment of PDAC, and provide a motivation for considering nutritional interventions during the treatment of patients with cancer.
Essential elements of radical pair magnetosensitivity in Drosophila
Authors: Bradlaugh Adam A. , Fedele Giorgio , Munro Anna L. , Hansen Celia Napier , Hares John M. , Patel Sanjai , Kyriacou Charalambos P. , Jones Alex R. , Rosato Ezio , Baines Richard A.
Published: February 2023

Many animals use Earth’s magnetic field (also known as the geomagnetic field) for navigation1. The favoured mechanism for magnetosensitivity involves a blue-light-activated electron-transfer reaction between flavin adenine dinucleotide (FAD) and a chain of tryptophan residues within the photoreceptor protein CRYPTOCHROME (CRY). The spin-state of the resultant radical pair, and therefore the concentration of CRY in its active state, is influenced by the geomagnetic field2. However, the canonical CRY-centric radical-pair mechanism does not explain many physiological and behavioural observations2–8. Here, using electrophysiology and behavioural analyses, we assay magnetic-field responses at the single-neuron and organismal levels. We show that the 52 C-terminal amino acid residues of Drosophila melanogaster CRY, lacking the canonical FAD-binding domain and tryptophan chain, are sufficient to facilitate magnetoreception. We also show that increasing intracellular FAD potentiates both blue-light-induced and magnetic-field-dependent effects on the activity mediated by the C terminus. High levels of FAD alone are sufficient to cause blue-light neuronal sensitivity and, notably, the potentiation of this response in the co-presence of a magnetic field. These results reveal the essential components of a primary magnetoreceptor in flies, providing strong evidence that non-canonical (that is, non-CRY-dependent) radical pairs can elicit magnetic-field responses in cells.