bluuebunny/crossref_metadata_2025 huggingface dataset:
Coexisting wave features and various nonlinear waves for Schrödinger equation in superthermal dusty plasma
Authors: Sarkar Satyajit , Kumari Prasad Punam , Saha Asit , Kumar Mondal Kajal
Published: February 2022

Coexistence of dust-acoustic wave (DAW) features and their properties are studied in a four-component dusty plasma constituting superthermal plasma particles in the framework of nonlinear Schrödinger equation (NLSE). Dynamical behaviors of the system are first explored by phase portraits and then the solutions corresponding to phase trajectories are explained analytically as well as numerically with physical perceptions. Introducing a periodic force, the system is analyzed for the existence of multi-periodic, quasiperiodic, and chaotic motions. Results of this work can be useful to understand the wave phenomena in the interstellar medium where superthermally distributed plasma particles are recognized.
Influence of polybenzimidazole nanoparticle on the thermo-mechanical characteristics of high density polyethylene composite
Authors: Mohan Ramesh , Kavan Panneerselvam
Published: February 2022

This present research focuses on the mechanical, thermal, flammability and thermo-mechanical behavior of varying percentages of high performance polymer polybenzimidazole (PBI) nanoparticle reinforced high density polyethylene (HDPE) composite. The principal aim of this present study was to investigate how the addition of polybenzimidazole nanoparticle influences the mechanical, thermal, flammability and thermo-mechanical behavior of high density polyethylene thermoplastic composite. The composites of polyethylene and polybenzimidazole were prepared by a melt intercalation process with different weight proportions as 1, 3 and 5 wt% using a twin-screw extruder. The prepared composites were characterized for their properties in-accordance to ASTM standards. The mechanical properties revealed significant improvements for PBI addition. The Scanning Electron Microscope (SEM) fractograph revealed moderate waviness and improved toughness. Similarly, the results of Thermo gravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) showed an increase in Tg and mass loss stability for 5 wt% of PBI. The Flammability and Dynamic mechanical analysis (DMA) results showed an increased flame resistance, damping and loss modulus for high concentration of PBI nanoparticle. These mechanically, thermally and thermo-mechanically toughened HDPE thermoplastic composites could be used in engineering, space, wearable material and defence applications where high toughness, high thermal stability structural materials are required.
Precision tests of CO and [CII] power spectra models against simulated intensity maps
Authors: Moradinezhad Dizgah Azadeh , Nikakhtar Farnik , Keating Garrett K. , Castorina Emanuele
Published: February 2022

Line intensity mapping (LIM) is an emerging technique with a unique potential to probe a wide range of scales and redshifts. Realizing the full potential of LIM, however, relies on accurate modeling of the signal. We introduce an extended halo model for the power spectrum of intensity fluctuations of CO rotational lines and [CII] fine transition line in real space, modeling nonlinearities in matter fluctuations and biasing relation between the line intensity fluctuations and the underlying dark matter distribution. We also compute the stochastic contributions beyond the Poisson approximation using the halo model framework. To establish the accuracy of the model, we create the first cosmological-scale simulations of CO and [CII] intensity maps, MithraLIMSims, at redshifts 0.5 ≤ z≤6, using halo catalogs from Hidden-Valley simulations, and painting halos according to mass-redshift-luminosity relations for each line. We show that at z=1 on scales kmax≲ 0.8 Mpc-11h, the model predictions of clustering power (with only two free parameters) are in agreement with the measured power spectrum at better than 5%. At higher redshift of z=4.5, this remarkable agreement extends to smaller scale of kmax≲ 2 Mpc-11h. Furthermore, we show that on large scales, the stochastic contributions to CO and CII power spectra are non-Poissonian, with amplitudes reproduced reasonably well by the halo model prescription. Lastly, we assess the performance of the theoretical model of the baryon acoustic oscillations (BAO) and show that hypothetical LIM surveys probing CO lines at z=1, that can be deployed within this decade, will be able to make a high significance measurement of the BAO. On a longer time scale, a space-based mission probing [CII] line can uniquely measure the BAO on a wide range of redshifts at an unprecedented precision.
Gamma-radiation sky maps from compact binaries
Authors: Ortiz Néstor , Carrasco Federico , Green Stephen R. , Lehner Luis , Liebling Steven L. , Westernacher-Schneider John Ryan
Published: February 2022

We study sky maps and light curves of gamma-ray emission from neutron stars in compact binaries, and in isolation. We briefly review some gamma-ray emission models, and reproduce sky maps from a standard isolated pulsar in the Separatrix Layer model. We consider isolated pulsars with several variations of a dipole magnetic field, including superpositions, and predict their gamma-ray emission. Our results provide new heuristics on what can and cannot be inferred about the magnetic field configuration of pulsars from high-energy observations. We find that typical double-peak light curves can be produced by pulsars with significant multipole structure beyond a single dipole. For binary systems, we also present a simple approximation that is useful for rapid explorations of binary magnetic field structure. Finally, we predict the gamma-ray emission pattern from a compact black hole-neutron star binary moments before merger by applying the Separatrix Layer model to data simulated in full general relativity; we find that face-on observers receive little emission, equatorial observers see one broad peak, and more generic observers typically see two peaks.
Bayesian analysis on non-resonant behavior of 12C + 12C fusion reaction at sub-barrier energies *
Authors: Luo Tian-Peng , Wen Pei-Wei , Lin Cheng-Jian , Yang Lei , Jia Hui-Ming , Yang Feng , Huang Da-Hu , Chang Chang , Zhang Ming-Hao , Yang Yun , Mo Teng-Huan , Ma Nan-Ru
Published: February 2022

Controversies exist among experiments and theories on the

factor of the astrophysical important reaction 12C + 12C for energies below 3 MeV. Only frequentist approaches have been used so far for data analysis, and the confidence levels or theoretical errors are not available from previous theoretical predictions. In this study, the Bayesian method is employed to provide theoretical predictions and its 1σ confidence level based on all the currently available experimental data for the first time. The improved coupled-channels model CCFULL-FEM implemented with the finite element method as well as the Markov chain Monte Carlo approach emcee are adopted to analyze the non-resonant behavior of this reaction. The posterior distribution of the Woods-Saxon potential parameters is investigated. Compared with the widely used frequentist method MIGRAD within the Minuit minimization program, the Bayesian method has a significant advantage for exploring the potential parameter space. When the existing experimental data measured down to subbarrier energies are considered, the potential parameters are constrained to a very narrow range, and the predictions of the

factor showed no sharp decrease in the low-energy region.
The Nonlinear Field Equation of the Three-point Correlation Function of Galaxies: to the Second Order of Density Perturbation
Authors: Wu Shu-Guang , Zhang Yang
Published: February 2022

Based on the field theory of density fluctuation under Newtonian gravity, we obtain analytically the nonlinear equation of 3-pt correlation function ζ of galaxies in a homogeneous, isotropic, static universe. The density fluctuation has been kept up to second order. By the Fry–Peebles ansatz and the Groth-Peebles ansatz, the equation of ζ becomes closed and differs from the Gaussian approximate equation. Using the boundary condition inferred from the data of SDSS, we obtain the solution ζ(r, u, θ) at fixed u = 2, which exhibits a shallow U-shape along the angle θ and, nevertheless, decreases monotonously along the radial r. We show its difference with the Gaussian solution. As a direct criterion of non-Gaussianity, the reduced Q(r, u, θ) deviates from the Gaussianity plane Q = 1, exhibits a deeper U-shape along θ and varies weakly along r, agreeing with the observed data.
Overground gait kinematics and muscle activation patterns in the Yucatan mini pig
Authors: Mirkiani Soroush , Roszko David A , O’Sullivan Carly L , Faridi Pouria , Hu David S , Fang Daniel , Everaert Dirk G , Toossi Amirali , Konrad Peter E , Robinson Kevin , Mushahwar Vivian K
Published: February 2022

Objective. The objectives of this study were to assess gait biomechanics and the effect of overground walking speed on gait parameters, kinematics, and electromyographic (EMG) activity in the hindlimb muscles of Yucatan minipigs (YMPs). Approach. Nine neurologically-intact, adult YMPs were trained to walk overground in a straight line. Whole-body kinematics and EMG activity of hindlimb muscles were recorded and analyzed at six different speed ranges (0.4–0.59, 0.6–0.79, 0.8–0.99, 1.0–1.19, 1.2–1.39, and 1.4–1.6 m s−1). A MATLAB program was developed to detect strides and gait events automatically from motion-captured data. The kinematics and EMG activity were analyzed for each stride based on the detected events. Main results. Significant decreases in stride duration, stance and swing times and an increase in stride length were observed with increasing speed. A transition in gait pattern occurred at the 1.0 m s−1 walking speed. Significant increases in the range of motion of the knee and ankle joints were observed at higher speeds. Also, the points of minimum and maximum joint angles occurred earlier in the gait cycle as the walking speed increased. The onset of EMG activity in the biceps femoris muscle occurred significantly earlier in the gait cycle with increasing speed. Significance. YMPs are becoming frequently used as large animal models for preclinical testing and translation of novel interventions to humans. A comprehensive characterization of overground walking in neurologically-intact YMPs is provided in this study. These normative measures set the basis against which the effects of future interventions on locomotor capacity in YMPs can be compared.
Isotope effect in turbulent transport in high density FT-2 tokamak discharges
Authors: Kouprienko D.V. , Gurchenko A.D. , Gusakov E.Z. , Altukhov A.B. , Askinazi L.G. , Belokurov A.A. , Dyachenko V.V. , Esipov L.A. , Ivanov V.A. , Kaledina O.A. , Lashkul S.I. , Shatalin S.V. , Sidorov A.V. , Tropin N.V. , Janhunen S.
Published: February 2022

A detailed study of the general transport properties of the FT-2 tokamak shows significant isotopic difference in ohmically heated quasi-stationary plasma in high density regimes 〈n
e〉 ≈ (6–9) × 1019 m−3. For deuterium, the signatures of a transition to the H-mode are found at a plasma density exceeding a certain value, while hydrogen plasma remains in L-mode in all comparable discharge scenarios. The origin of this isotopic discrepancy is studied both with energy transport analysis and direct turbulence and plasma velocity measurements performed with Langmuir probes and microwave diagnostics. A special, more complicated dynamic experimental series with current ramp up, performed in these high density regimes, demonstrated the stability and robustness of an improved energy confinement in deuterium, whereas a comparable confinement improvement in hydrogen plasma was observed.
The global potential of forest restoration for drought mitigation
Authors: Tuinenburg Obbe A , Bosmans Joyce H C , Staal Arie
Published: February 2022

Forest restoration is increasingly applied as a climate change mitigation measure. Apart from sequestering carbon, the large-scale addition of trees on Earth may enhance global precipitation levels. Here we estimate the global precipitation effects of the global forest potential by estimating its effects on evaporation and simulating the downwind precipitation effect of the moisture added to the atmosphere. We find that maximum forestation would on average increase evaporation by 0.6 mm d−1 and that two-thirds of that additional evaporation would rain out over land, especially during the growing season. Next, by excluding natural grasslands and prioritizing precipitation enhancement above areas that are projected to become drier due to global climate change, we establish where on Earth forest restoration would have the greatest precipitation benefits. Our results thus provide a first step towards forest restoration programs as double climate-change mitigation efforts.
Quantum violations of L

u¨

ders bound Leggett–Garg inequalities for non-unitary quantum channel
Authors: Kumari Asmita , Pan A K
Published: February 2022

Leggett Garg inequalities (LGIs) provides an elegant way for probing the incompatibility between the notion of macrorealism and quantum mechanics. For unitary dynamics the optimal quantum violation of a LGI is constrained by the L

u

¨

ders bound. In this paper, we have studied two formulations of LGIs in three-time LG scenario, viz, the standard LGIs and third-order LGIs both for unbiased and biased measurement settings. We show that if system evolves under non-unitary quantum channel between two measurements, the quantum violations of both forms of LGIs exceed their respective L

u

¨

ders bounds and can even reach their algebraic maximum in sharp measurement settings. We found that when the measurement is unsharp the quantum violations of both standard and third-order LGIs for non-unitary quantum channel can be obtained for lower value of the unsharpness parameter compared to the unitary dynamics. We critically examined the violation of L

u

¨

ders bound of LGIs and its relation to the violation of various no-signaling in time conditions, another formalism for testing macrorealism. It is shown that mere violations of no-signaling conditions are not enough to warrant the violation of standard LGIs, an interplay between the violations of various NSIT condition along with a threshold value play an important role. On the other hand violation of third-order LGI is obtained when the degree of violation of a specific no-signaling in time condition reaches a different threshold value.
Optimizing the Physical Properties of Waste Denim Fiber-Modified Rubberized Bitumen Through Response Surface Methodology
Authors: Al-Sabaeei A M , Napiah M , Al Salaheen M , Badri R M , Noura S , Khan M I , Al-Bahr T M , Alzubi K
Published: February 2022

In this study, waste denim fiber (WDF) was used as a modifier to enhance the properties of bitumen incorporating tire pyrolysis oil (TPO). The designing of the experiment, analysis data, modeling and multi-objective optimization performed using response surface methodology (RSM). Base bitumen was modified with 0%, 5%, 10% and 15% TPO and 0%, 2%, 4% and 6% of WDF using high shear mixer. The interaction effects of TPO and WDF on the penetration, softening point and temperature susceptibility of bitumen were evaluated. Results showed that the addition of TPO and/or WDF has a significant effect on the consistency and temperature susceptibility of base bitumen. RSM analysis exhibited high degrees of correlation (R2) of 0.982, 0.973 and 0.947 for the dependent variables’ penetration, softening point and temperature susceptibility, respectively. That indicates there is an adequate agreement between models developed by RSM and experimental results. The numerical multi-objective optimization showed that optimum properties can be achieved with 8.4% of TPO and 6% of WDF.
Evaluating the Quality of Service of Bus Performance in Johor Bahru
Authors: Bakar M F A , Norhisham S , Abudeyab N H Z Ibrahim A , Saad N M , Azlan N N I M , Shkuri N S M , Mohamad A M
Published: February 2022

The increase in living standard would also be a major factor for rapid urban development, which is caused by the increase in the daily traffic volume. Therefore, traffic congestion can occur daily, especially during peak hours in the morning and late afternoon to cover the huge number of people movement. Moreover, the quality of bus services should be assessed on operational aspects provided by urban operators. Therefore, this paper is to determine the quality of service (QOS) of bus performance in Johor Bahru, Johor. The study was conducted in April 2019. Service quality data were taken at Terminal JB Sentral, Johor Bahru. The Transit Capacity and Quality of Service Manual (TCRPM) was adopted as the specific guidelines and key indicators to determine and analyse the QOS of bus performance in the selected area. The study focused on four specific areas, such as service hour, passenger load factor, on-time performance and service frequency. The study concluded that the passenger load factor was classified as QOS of Class B since passengers could still choose their seats during the journey. On the other hand, on-time performance was classified as QOS of Class E, as most passengers made one round trip per weekday with a transfer experience of not-on-time vehicles every day. The overall QOS for bus services in Johor Bharu was classified as QOS of Class D, which was considered as moderate because several issues on QOS should be addressed and rectified by stakeholders. Some improvement on these three attributes should be made to increase the QOS. The study outcome should be used as an indicator for operators to measure their bus services. Since Johor Bahru is a major city in Malaysia, authorities and the government can use the outcome as inputs to measure the effectiveness of public transportation in urban areas.
Study Restraint Pressure of Membranes on Expansive Soil
Authors: Fitriyana L , Dian A G , Darwis F
Published: February 2022

Type of deformation in expansive soil is lateral and vertical Laboratory expansion tests are often performed on rings with restrained, lateral movement so that horizontal, swelling deformation will not occur. The road damage in the highway between Purwodadi – Semarang (Begel village, Purwodadi) was identified because the soil is expansive. Therefore, this study was conducted to identify characteristics of its soil expansion, specifically the influence of pressure of membrane restraints on expansion of expansive soil. The expansion test was conducted on modified test tools. The axial expansion strain was measured using the dial gauge which was installed in parallel, vertical position while the lateral strain was measured using the caliper digital in order to identify any change in the diameter of sample with the variations of initial water content (wo), vertical pressure (pv) and membrane’s thickness (t). The test result show that the greater the (horizontal) lateral strain is, the greater the restraint pressure in the membranes will be. The restraint pressure in the membranes (ph) is closely related to factors that influence the expansion possibility such as vertical pressure (pv), initial height of test object (ho), initial water content (wo), and membrane’s thickness (t).
Numerical and experimental simulation of a dynamic-rotational 3D cell culture for stratified living tissue models
Authors: Canadas Raphaël F , Liu Ziyu , Gasperini Luca , Fernandes Diogo C , Maia Fátima R , Reis Rui L , Marques Alexandra P , Liu Chaozong , Oliveira Joaquim M
Published: February 2022

Human tissues and organs are inherently heterogeneous, and their functionality is determined by the interplay between different cell types, their secondary architecture, and gradients of signalling molecules and metabolites. To mimic the dynamics of native tissues, perfusion bioreactors and microfluidic devices are widely used in tissue engineering (TE) applications for enhancing cell culture viability in the core of 3D constructs. Still, most in vitro screening methods for compound efficacy and toxicity assessment include cell or tissue exposure to constant and homogeneous compound concentrations over a defined testing period. Moreover, a prevalent issue inhibiting the large-scale adoption of microfluidics and bioreactor is the tubing dependence to induce a perfusion regime. Here, we propose a compartmentalized rotational (CR) 3D cell culture platform for a stable control over gradient tissue culture conditions. Using the CR bioreactor, adjacent lanes of constructs are patterned by controlled flow dynamics to enable tissue stratification. Numerical and experimental simulations demonstrate cell seeding dynamics, as well as culture media rotational perfusion and gradient formations. Additionally, the developed system induces vertical and horizontal rotations, which increase medium exchange and homogeneous construct maturation, allowing both perfused tubing-based and tubing-free approaches. As a proof-of-concept, experiments and accompanying simulation of cellular inoculation and growth in 3D scaffold and hydrogel were performed, before the examination of a blood-brain-barrier model, demonstrating the impact of a heterotypic culture on molecular permeability under mimetic dynamic conditions. Briefly, the present work discloses the simulation of 3D dynamic cultures, and a semi-automated platform for heterotypic tissues in vitro modelling, for broad TE and drug discovery/screening applications.
Enhanced fluorescence of CsPbBr3/ZnO heterojunction enabled by titanium nitride nanoparticles
Authors: Jiang Jinguo , Bai Zhongchen , Yao Heng , Qin Shuijie
Published: February 2022

We prepared CsPbBr3/ZnO heterojunctions by self-assembling colloidal CsPbBr3 quantum dots (QDs) on the surface of the ZnO film. The fluorescence of CsPbBr3/ZnO heterojunctions was modulated by titanium nitride nanoparticles (TiN NPs) to obtain highly photoluminescent CsPbBr3/TiN/ ZnO heterojunctions. The results showed that when the TiN thickness was 51 nm, the fluorescence of the CsPbBr3/TiN/ZnO heterojunction was enhanced by 3.2 times compared to that of the CsPbBr3/ZnO heterojunction. TiN NPs combined most of the photo-generated electrons with the holes on the surface of the TiN/CsPbBr3 heterojunction, which increased the electron transfer rate and reduced non-radiative recombination. This method of enhancing heterojunction fluorescence could provide a new pathway for photovoltaic, light-emitting diode (LED), photodetector, light sensor, and image sensor applications.
Compatibilization, processing and characterization of poly(butylene adipate terephthalate)/polylactide (PBAT/PLA) blends
Authors: Su Shen
Published: February 2022

A blend of poly(butylene adipate terephthalate) (PBAT) and polylactide (PLA) is a combination of biodegradable materials. This study aims to prepare compatibilized PBAT/PLA in a cost-effective and timesaving way and to process the material into blown films by fine-tuning the processing parameters. First, a catalyst masterbatch is prepared by transesterification of PBAT and PLA in the presence of tetrabutyl titanate (TBT) as a catalyst. This is followed by the compounding of the two polymer types in combination with the catalyst masterbatch. Third, the compounds are processed into blown films and panels. The processing parameters for film blowing are set to reduce the anisotropy. Finally, the material properties are evaluated such as mechanical tests. The fine-tuning of parameter settings including the blow-up ratio and draw-down ratio results in a higher degree of isotropy of the blown film. By adding the catalyst masterbatch (2 wt%, which corresponds to TBT of approximately 0.002 wt% with copolymers formed) in combination with the fine-tuning of parameter settings, the samples achieved a significant improvement on the material properties. The morphology of the cryogenically fractured panel samples shows a decrease in the diameter of the dispersed phase. In the cross and machine directions, the elongation at break increased by 85 and 93%, and the trouser tear propagation resistance increased by 2.4 and 10 N mm−1, respectively. Furthermore, both the elongation at break and the trouser tear propagation of the blown films achieved a higher degree of isotropy.
Harold Widom’s work in Toeplitz operators
Authors: Basor Estelle , Böttcher Albrecht , Ehrhardt Torsten
Published: February 2022

This is a survey of Harold Widom’s work in Toeplitz operators, embracing his early results on the invertibility and spectral theory of Toeplitz operators, his investigations of the eigenvalue distribution of convolution operators, and his groundbreaking research into Toeplitz and Wiener–Hopf determinants.
Tropical floor plans and enumeration of complex and real multi-nodal surfaces
Authors: Markwig Hannah , Markwig Thomas , Shaw Kris , Shustin Eugenii
Published: February 2022

The family of complex projective surfaces in

P

3

\mathbb {P}^3

of degree

d
d

having precisely

δ
\delta

nodes as their only singularities has codimension

δ
\delta

in the linear system

|

O

P

3

(
d
)

|

|{\mathcal O}_{\mathbb {P}^3}(d)|

for sufficiently large

d
d

and is of degree
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper N Subscript delta comma double-struck upper C Superscript double-struck upper P cubed Baseline left-parenthesis d right-parenthesis equals left-parenthesis 4 left-parenthesis d minus 1 right-parenthesis cubed right-parenthesis Superscript delta Baseline slash delta factorial plus upper O left-parenthesis d Superscript 3 delta minus 3 Baseline right-parenthesis">

N

δ
,

C

P

3

(
d
)
=
(
4
(
d
−
1

)
3

)
δ

/

δ
!
+
O
(

d

3
δ
−
3

)

N_{\delta ,\mathbb {C}}^{\mathbb {P}^3}(d)=(4(d-1)^3)^\delta /\delta !+O(d^{3\delta -3})

. In particular,

N

δ
,

C

P

3

(
d
)

N_{\delta ,\mathbb {C}}^{\mathbb {P}^3}(d)

is polynomial in

d
d

.

By means of tropical geometry, we explicitly describe

(
4

d
3

)
δ

/

δ
!
+
O
(

d

3
δ
−
1

)

(4d^3)^\delta /\delta !+O(d^{3\delta -1})

surfaces passing through a suitable generic configuration of

n
=

(

d
+
3

3

)

−
δ
−
1

n=\binom {d+3}{3}-\delta -1

points in

P

3

\mathbb {P}^3

. These surfaces are close to tropical limits which we characterize combinatorially, introducing the concept of floor plans for multinodal tropical surfaces. The concept of floor plans is similar to the well-known floor diagrams (a combinatorial tool for tropical curve counts): with it, we keep the combinatorial essentials of a multinodal tropical surface

S
S

which are sufficient to reconstruct

S
S

.

In the real case, we estimate the range for possible numbers of real multi-nodal surfaces satisfying point conditions. We show that, for a special configuration

w
\boldsymbol {w}

of real points, the number

N

δ
,

R

P

3

(
d
,
w
)

N_{\delta ,\mathbb {R}}^{\mathbb {P}^3}(d,\boldsymbol {w})

of real surfaces of degree

d
d

having

δ
\delta

real nodes and passing through

w
\boldsymbol {w}

is bounded from below by

(

3
2

d
3

)

δ

/

δ
!
+
O
(

d

3
δ
−
1

)

\left (\frac {3}{2}d^3\right )^\delta /\delta ! +O(d^{3\delta -1})

.

We prove analogous statements for counts of multinodal surfaces in

P

1

×

P

2

\mathbb {P}^1\times \mathbb {P}^2

and

P

1

×

P

1

×

P

1

\mathbb {P}^1\times \mathbb {P}^1\times \mathbb {P}^1

.
Periods of tropical Calabi–Yau hypersurfaces
Authors: Yamamoto Yuto
Published: February 2022

We consider the residual B-model variation of Hodge structure of Iritani defined by a family of toric Calabi–Yau hypersurfaces over a punctured disk

D
∖

{
0
}

D \setminus \left \{ 0\right \}

. It is naturally extended to a logarithmic variation of polarized Hodge structure of Kato–Usui on the whole disk

D
D

. By restricting it to the origin, we obtain a polarized logarithmic Hodge structure (PLH) on the standard log point. In this paper, we describe the PLH in terms of the integral affine structure of the dual intersection complex of the toric degeneration in the Gross–Siebert program.
The flocking behavior of the infinite-particle Cucker-Smale model
Authors: Wang Xinyu , Xue Xiaoping
Published: February 2022

In this article, we study the flocking behavior of the solutions to the infinite-particle Cucker-Smale model. We first establish the existence and uniqueness of the solutions to the infinite-particle Cucker-Smale model. And then build the boundedness of velocity by showing the non-increase of the

l
∞

l_\infty

-norm of

v
(
t
)

v(t)

through classifying the particles according to the norm of velocity. Finally, we obtain the flocking behavior of the infinite-particle Cucker-Smale model. More precisely, the solutions to the infinite-particle Cucker-Smale model will concentrate exponentially fast in velocity to the average of the initial velocity, while in space the position differences between particles will be uniformly bounded.
Cross-ratio degrees and perfect matchings
Authors: Silversmith Rob
Published: February 2022

Cross-ratio degrees count configurations of points

z
1

,
…
,

z
n

∈

P

1

z_1,\ldots ,z_n\in \mathbb {P}^1

satisfying

n
−
3

n-3

cross-ratio constraints, up to isomorphism. These numbers arise in multiple contexts in algebraic and tropical geometry, and may be viewed as combinatorial invariants of certain hypergraphs. We prove an upper bound on cross-ratio degrees in terms of the theory of perfect matchings on bipartite graphs. We also discuss several of the many perspectives on cross-ratio degrees—including a connection to Gromov-Witten theory—and give many example computations.
Wartime Dollars and the Crowning of China’s Hog Bristle King
Authors: Kinzley Judd
Published: February 2022

US war mobilization efforts in the early 1940s helped create demand for a vast assortment of raw materials not produced in the domestic United States. These demands led to the formation of a new foreign aid regime that sought to procure strategic materials in exchange for loans, cash, and industrial and military goods. This essay, which draws on archival sources collected in China, Taiwan, and the United States, examines the power and legacy of US overseas procurement programs by focusing on the case of China and the US effort to acquire hog bristles. Hog bristles, which were used for the production of a vast assortment of brushes, were one of China’s largest wartime exports. The US wartime demand for bristles helped empower a small number of Chinese firms that controlled local production. One of these firms used wartime controls to dominate the industry by 1945, and the head of the firm, Gu Gengyu, was later deemed the “hog-bristle king.” This essay explores the long-term legacies of US wartime procurement programs, revealing how they helped empower a new and powerful class of transnational businessmen with strong ties to the government, as well as deep connections to US markets.
“That City Af loat”
Authors: McMahon Cian T
Published: February 2022

Throughout the eighteenth and nineteenth centuries, millions of migrants from every corner of the earth spent weeks and sometimes months at sea. Yet these ubiquitous voyages appear as little more than blank pages in the annals of human migration. Maritime social history has grown considerably over the past thirty years, offering brilliant new insights into the lived experiences of sailors, pirates, and slaves. But the lowly emigrant has been largely ignored. At the same time, scholars carefully tracing the development of migrant communities at the local, national, and transnational levels have tended to reify the historiography’s traditional terracentrism. Using the letters, diaries, and printed guides of those who left Ireland during the Great Famine, this article seeks to understand how the journey itself shaped community building in the Irish diaspora. It argues that the hardships of life at sea encouraged disparate groups of people to expand their traditional ideas of belonging. Localism and ethnic identity did not dissolve at sea, they changed—making room for new and heterogeneous links of solidarity anchored in shared experience.
Taking the Temperature: An Intersectional Examination of Diversity Acceptance in Canadian Police Services
Authors: Bikos Lesley J
Published: February 2022

This exploratory study analyses data from in-depth interviews (116 from 31 police services across Canada) and an online survey (N = 727) to examine how gender and racial ideologies inform ongoing cultural and structural adherence to hegemonic whiteness and masculinity, impacting who has power (and who does not) within the institution of policing. White, cisgender, heterosexual men were the most likely to present views consistent with white supremacist patriarchy. Their ongoing cultural, structural, and material power created gatekeeping conditions that are at least part of the explanation for barriers to the recruitment and promotion of racialized women, men, and white women. Findings also reveal that a significant proportion of white women and some racialized men also upheld these ideologies, indicating cultural-level buy-in. There were disrupters who attempted to influence cultural and structural change, but barriers and resistance at leadership levels remain. Thus, this study adds to the growing body of evidence that diversity representation alone has not, and will not, transform the institution in a timely and meaningful way.
Affinity and the classroom: informal and formal L2 learning
Authors: Brevik Lisbeth M , Holm Thea
Published: February 2022

Connecting informal and formal language teaching and learning has gained prominence as a way to understand language development among teenagers, but questions remain regarding its application in L2 contexts. This study investigates the significance of such connections in two L2 English classes taught by the same teacher, where students were learning English during a technology-based project, the Time Traveller. We collected data during three weeks of fieldwork at a Norwegian secondary school. We found that informal and formal language teaching and learning were connected in two ways: the students’ use of English outside school was primarily linked to online game play and social media, and the teacher was able to design activities that extended her students’ existing affinity space, resulting in the students using English in the classroom more frequently and more confidently than before. Implications include the importance of understanding students’ informal language learning to rethink L2 teaching practices.
Reconstruction of Nitrogenase Predecessors Suggests Origin from Maturase-Like Proteins
Authors: Garcia Amanda K , Kolaczkowski Bryan , Kaçar Betül
Published: February 2022

The evolution of biological nitrogen fixation, uniquely catalyzed by nitrogenase enzymes, has been one of the most consequential biogeochemical innovations over life’s history. Though understanding the early evolution of nitrogen fixation has been a longstanding goal from molecular, biogeochemical, and planetary perspectives, its origins remain enigmatic. In this study, we reconstructed the evolutionary histories of nitrogenases, as well as homologous maturase proteins that participate in the assembly of the nitrogenase active-site cofactor but are not able to fix nitrogen. We combined phylogenetic and ancestral sequence inference with an analysis of predicted functionally divergent sites between nitrogenases and maturases to infer the nitrogen-fixing capabilities of their shared ancestors. Our results provide phylogenetic constraints to the emergence of nitrogen fixation and are consistent with a model wherein nitrogenases emerged from maturase-like predecessors. Though the precise functional role of such a predecessor protein remains speculative, our results highlight evolutionary contingency as a significant factor shaping the evolution of a biogeochemically essential enzyme.
Lysosomal ceramides regulate cathepsin B-mediated processing of saposin C and glucocerebrosidase activity
Authors: Kim Myung Jong , Jeong Hyunkyung , Krainc Dimitri
Published: February 2022

Variants in multiple lysosomal enzymes increase Parkinson’s disease (PD) risk, including the genes encoding glucocerebrosidase (GCase), acid sphingomyelinase (ASMase) and galactosylceramidase. Each of these enzymes generates ceramide by hydrolysis of sphingolipids in lysosomes, but the role of this common pathway in PD pathogenesis has not yet been explored. Variations in GBA1, the gene encoding GCase, are the most common genetic risk factor for PD. The lysosomal enzyme cathepsin B has recently been implicated as an important genetic modifier of disease penetrance in individuals harboring GBA1 variants, suggesting a mechanistic link between these enzymes. Here, we found that ceramide activates cathepsin B, and identified a novel role for cathepsin B in mediating prosaposin cleavage to form saposin C, the lysosomal coactivator of GCase. Interestingly, this pathway was disrupted in Parkin-linked PD models, and upon treatment with inhibitor of ASMase which resulted in decreased ceramide production. Conversely, increasing ceramide production by inhibiting acid ceramidase activity was sufficient to upregulate cathepsin B- and saposin C-mediated activation of GCase. These results highlight a mechanistic link between ceramide and cathepsin B in regulating GCase activity and suggest that targeting lysosomal ceramide or cathepsin B represents an important therapeutic strategy for activating GCase in PD and related disorders.
Integral Points of Bounded Height on a Log Fano Threefold
Authors: Wilsch Florian
Published: February 2022

We determine an asymptotic formula for the number of integral points of bounded height on a blow-up of ${\mathbb {P}}^3$ outside certain planes using universal torsors.
P27 Bacterial coinfection and antibiotic stewardship in patients with COVID-19: a systematic review and meta-analysis
Authors: Calderon Maria , Gysin Grace , Walpole Sarah , Mills Felicity , Comandé Daniel , Hunter Ewan
Published: February 2022

Introduction

Understanding the proportion of patients with COVID-19 who have respiratory bacterial coinfections and the responsible pathogens is important to managing COVID-19 effectively while ensuring responsible antibiotic use.

Objectives

To estimate the frequency of bacterial coinfection in COVID-19 patients and of antibiotic prescribing and to appraise the use of antibiotic stewardship criteria.

Methods

Systematic review and meta-analysis was performed using major databases up to May 15, 2020. We included studies that reported a) proportion/prevalence of bacterial coinfection in COVID-19 patients and b) use of antibiotics. Where available, data on duration and type of antibiotics, adverse events, and any information about antibiotic stewardship policies were also collected.

Results

We included 39 studies with a total of 10 815 patients. The overall prevalence of bacterial coinfection was 10.6% (95% CI 6.8%–14.3%). When only confirmed bacterial coinfections were included the prevalence was 4.6% (95% CI 2.9%–7%). Thirty-five bacterial species were identified, the most frequent being Mycoplasma pneumoniae (n = 12 [34%]), Pseudomonas aeruginosa (n = 4 [11.4%]) and Legionella pneumophila (n = 2 [6%]). The overall antibiotic use was 71.3% (95% CI 63.1%–79.5%). Only one study described criteria for stopping them. All included studies had a moderate to high risk of bias.

Conclusions

There is currently insufficient evidence to support widespread empirical use of antibiotics in most hospitalized patients with COVID-19, as the overall proportion of bacterial coinfection is low. Furthermore, as the use of antibiotics appears currently to be largely empirical, it is necessary to formulate clinical guidelines to promote and support more targeted administration of antibiotics in patients admitted to hospital with COVID-19.
P34 Impact of medical microbiology lead antimicrobial stewardship rounds on antimicrobial consumption in a level 3 hospital
Authors: Lucey Mary , O’Regan Sabrina , Waldron Ruth
Published: February 2022

Background

No onsite consultant medical microbiologist (CMM) was available in this centre from September 2018 to November 2019. During this time antimicrobial stewardship (AMS) rounds were carried out by the antimicrobial pharmacist (AMP) with feedback provided directly to clinical teams. Antimicrobial consumption rose from 88.81 DDD/bed-days used (DDD/BDU) in 2017 to 95.57 DDD/BDU in 2019. The aim of this study was to assess the impact of AMS service led by a CMM.

Methods

A structured antimicrobial stewardship programme has been in place since 2013. The re-addition of an onsite CMM in November 2019 facilitated new AMS initiatives, including ward based, targeted antimicrobial rounds, team audits and education sessions led by the CMM. These rounds focused on the choice of antimicrobial agent and duration of therapy.

Results

Overall antimicrobial consumption decreased from 95.57 DDD/BDU in 2019 to 82.16 DDD/BDU (14% reduction) in 2020. The addition of team-based AMS rounds with a CMM and AMP alongside the clinical team enhanced the existing AMS programme and appeared to have the most benefit in reducing antimicrobial consumption. Increases in consumption were noted during weeks where there was poor attendance or cancellation of the AMS rounds.

Conclusions

AMS is most effective with specialty leadership and a multidisciplinary approach. Continuous intervention is required in order to sustain improvements. AMS programmes have been shown to reduce the incidence of healthcare-associated infection and have a positive impact on antimicrobial resistance. AMS should be prioritized by healthcare institutions for increased investment.
P36 Procalcitonin as an antimicrobial stewardship tool in the COVID-19 era: a single centre experience
Authors: Creedon Margaret , Talento Alida Fe , Connolly Roisin , Egan Aine , Hassan Tidi , Trzos-Grzybowksa Marta
Published: February 2022

Background

Procalcitonin (PCT) is a biomarker which may have greater specificity than other pro-inflammatory markers in identifying bacterial infection and may aid in antimicrobial stewardship in COVID-19 patients.

Methods

A PCT assay by Abbott diagnostics was introduced in our hospital in November 2020. Over a 12 week period, we prospectively recorded all PCT results on in-patients with COVID-19 admitted to the ICU, as well as stewardship actions taken following discussion with the ICU physicians. Microbiology records were reviewed to ascertain whether bacterial infection was subsequently confirmed.

Results

Sixty-four PCT results were recorded on 27 patients (Table 1). Antimicrobials were discontinued on 12 occasions and withheld on 16 occasions where PCT was <0.5 ng/mL. No cases of confirmed bacterial infection were diagnosed in patients with PCT concentrations of <0.05 ng/mL; however definite bacterial infection was confirmed in two patients (one case of Staphylococcus aureus bloodstream infection; one case of Staphylococcus epidermidis CVC infection), and bacterial infection was designated probable in five patients with PCT ≥0.05 ng/mL and <0.5 ng/mL.

Conclusions

PCT may be a useful tool in enabling antimicrobial stewardship actions in patients with severe COVID-19, but results need to be interpreted within the clinical context.
P39 Bloodstream infections (BSI) in tertiary ICU—an update!
Authors: Patel Veer M. , Desai Seema
Published: February 2022

Background

Patients in ICU represent a small proportion of inpatients; however they account for up to 25% of all hospital acquired infections (HAI) and are 2–5 times more likely to develop a HAI than the average patient. Management of bloodstream infections (BSI) in ICU is a rising problem due to increasing antibiotic resistance posing challenges to antimicrobial stewardship (AMS) leading to higher mortality in ITU patients. It increases duration of inpatient stay, hospital costs and worsens prognosis.

Objectives

To find all-cause mortality in patients with BSI admitted to intensive care at 14 and 28 days from admission.

Methods

We used retrospective patient data from the hospital database between March 2019 to March 2020.

Results

We included 113 patients admitted to ICU and had BSI, of which 12.4% died at 14 days and 24.8% died at 28 days with overall mortality of 33.6% at discharge. Respiratory comorbidity was found significantly higher (48.1%). Patients with Gram-negative BSI had higher mortality with 14.29% at 14 days when compared with Gram-positive BSI, but 28 day mortality was similar in both groups (25.71% and 25% respectively), which is concerning.

Conclusions

This study concludes that patients admitted to ICU have higher mortality at 28 days irrespective of the pathogen isolated in the bloodstream. This could be explained due to prolonged stay in ICU leading to increased burden from HAI. Future AMS will have to focus on a prevention model for this cohort to improve patient outcome.
P40 Kitchen sponges—home sweet home for carbapenem-resistant Klebsiella spp.
Authors: Debergh H. , Delbrassinne L. , Garcia-Graells C. , Hoorde K. Van
Published: February 2022

Background

Although research on foodborne diseases is well documented for certain microorganisms, less research has been undertaken on cross-contamination with Enterobacteriaceae from food within the kitchen environment. In this study, we analysed the presence of Klebsiella spp. and Raoultella spp. and their antibiotic resistance in 100 used kitchen sponges. In a domestic environment, kitchen sponges are commonly used by consumers for doing the dishes and/or cleaning kitchen surfaces. Given their multipurpose use, their often high humidity and presence of organic residuals they are considered a favourable habitat for various groups of microorganisms and could serve as a vehicle in transmission of foodborne pathogens.1,2

Material and methods

A total of 100 kitchen sponges alongside a questionnaire regarding hygienic parameters were randomly collected from domestic environments and analysed within 24 h after arrival in the lab. Kitchen sponges were immersed in 100 mL buffered peptone water, homogenized and incubated at 37°C for 24 h ± 2 h. Ten microlitres of this enrichment was plated on MacConkey agar (Bio-Rad) and incubated at 37°C for 24 h ± 2 h. Presumptive Klebsiella spp. and Raoultella spp. were isolated and confirmed by MALDI-TOF MS. Antibiotic resistance testing (ART) was performed on all Klebsiella spp. and Raoultella spp. isolates following the EUCAST guidelines. WGS was performed using the Illumina platform.

Results

A total of 65% of the kitchen sponges were positive for Klebsiella spp. or Raoultella spp. The species Klebsiella oxytoca was detected in 78.5% of positive samples, followed by Klebsiella pneumoniae (12.31%), Raoultella ornithinolytica (4.62%), Klebsiella variicola (1.54%), Klebsiella aerogenes (1.54%) and Raoultella planticola (1.54%). To the best of our knowledge this is the first study performed on detection of Klebsiella spp. in kitchen sponges from Belgium and has comparable results with previous studies.1–3 We hypothesize the high positivity rate is caused by cross-contamination. ART revealed the presence of one carbapenem-resistant isolate, with resistance to ertapenem and meropenem. Reduced susceptibility to carbapenems was caused by the presence of blaSHV-36 combined with porin deficiency. Klebsiella spp. can be part of the commensal flora of human intestines but are considered to be opportunistic pathogens. Klebsiella spp. might present antimicrobial resistance and carbapenem-resistant Enterobacteriaceae are taken up in the WHO global priority list of antibiotic-resistant bacteria.

Conclusions

High prevalence of Klebsiella spp. and a carbapenem-resistant isolate in kitchen sponges highlight the occurrence of cross-contamination from food and the possible risks for foodborne disease associated with this kitchen tool. These findings advocate for good hygienic measures within a household setting.