bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the selection of vegetation for ecological restoration of residual soil slopes in South China
Authors: De-yong Wang , Jun-long Hu , Jing Wang , Qingjun Zun
Published: October 2020

Vegetation selection is one of the key contents of slope ecological restoration, based on the characteristics of climate and soil in South China and the principle of local conditions, this paper studies the selection of vegetation in the ecological restoration project of the residual soil slope. The typical herbs, shrubs and trees suitable for the area are determined by theoretical analysis. At the same time, through field tests, the growth and development of vegetation after the spraying are monitored for a long time, and the interaction relationship between vegetation community after multiple vegetation mix-ups is analyzed. The results show that plant selection should avoid the choice of a single plant, and should try to achieve complementary coordination between species. At the same time, when taking a variety of plant mixing spray, the configuration ratio of different plants should be determined according to the growth cycle of different plants and the results of indoor ratio test, so as to avoid mutual interference.
A mixed PGD-a priori time basis strategy for the simulation of cyclic transient thermal behavior
Authors: Al Takash Ahmad , Beringhier Marianne , Hammoud Mohammad , Grandidier Jean-Claude
Published: October 2020

The knowledge of the service life of polymers under cyclic loading, widely used in industrial applications, is required and usually based on the use of methods necessitating an accurate prediction of the stabilized cycle. This implies a large computation time using the Finite Element Method (FEM) since it requires a large number of cycles for polymers. To alleviate this difficulty, a model order reduction method can be used. In this paper, a mixed strategy is investigated. Through the Proper Generalized Decomposition Method (PGD) framework, this strategy combines the Fast Fourier Transform (FFT) to create a priori time basis and the FEM to compute the related spatial modes. The method is applied to 3D thermal problems under cyclic loadings. The robustness of the proposed strategy is discussed for various boundary conditions, multi-times, and different cyclic loadings. A large time saving is obtained proving the interest of this alternative strategy to deal with fatigue simulations.
Weitere Studien für klare klinische Empfehlungen notwendig
Authors: Lecheler Leopold , Noppe Alexandra , Frett Timo , Koch Susanne , Löhr Patricia , Hemmersbach Ruth
Published: October 2020

Astronauten berichten im Rahmen von Raumflügen über Symptome im Sinne von Kinetosen (engl. „(Space) Motion Sickness“), welche innerhalb der ersten 72 Stunden in der Schwerelosigkeit zu teils deutlicher Beeinträchtigung führen 1. Zur Erforschung der Auswirkungen von Schwerelosigkeit werden Parabelflüge durchgeführt, um den Effekt der Mikrogravitation zu untersuchen 2. Auch hierbei leiden die der Schwerelosigkeit ausgesetzten Menschen unter ähnlichen Beschwerden. Die Autoren der vorgestellten Studie versuchen, beobachtend anhand von 246 Parabelflugberichten, das Problem der assoziierten Kinetosen zu erfassen und prädiktive sowie modifizierende Faktoren zu identifizieren.
Recent Advances in the Tandem Cyclization/Cycloaddition of Allene Intermediates from Copper-Catalyzed Cross-Coupling of Diazo Compounds with Terminal Alkynes
Authors: Peng Shiyong , Chen Nuan , He Min , Zhou Ting , Zhu Yuqi , Zhang Hong
Published: October 2020

This short review summarizes the most recent developments (since 2010) in the tandem cyclization/cycloaddition of allene intermediates­, generated from the copper-catalyzed cross-coupling of diazo compounds with terminal alkynes, to afford cyclic compounds.

1 Introduction

2 Cyclization

2.1 Cyclization with Nucleophiles

2.2 Cyclization with Electrophiles

2.3 6π-Electrocyclization

2.4 Other Cyclization

3 Cycloaddition

4 Conclusion
Cervical Myelopathy as a Complication of Untreated Motor Tics: A Cautionary Tale
Authors: Hull Mariam , Parnes Mered
Published: October 2020

Tic disorders are common, affecting approximately 0.5 to 1% of children and adolescents. Treatment is required only when symptoms are bothersome or impairing to the patient, so many do not require intervention. However, on occasion tics may cause significant morbidity and are referred to as “malignant.” These malignant tics have resulted in cervical myelopathy, subdural hematoma secondary to head banging, biting of lips leading to infection of oral muscles, self-inflicted eye injuries leading to blindness, skeletal fractures, compressive neuropathies, and vertebral artery dissection. We describe a case of malignant tic disorder, with accompanying video segment, resulting in cervical myelopathy and quadriparesis in a child. We also discuss aggressive management strategies for neurologists to prevent potential lifelong disability. This case emphasizes that these malignant tics must be treated with all due haste to prevent such complications.
An experimental investigation of a square supersonic jet and impinging jet on an inclined plate
Authors: Nguyen Thien , Maher Blake , Hassan Yassin
Published: October 2020

Supersonic free jets and impinging jets are found in many engineering applications, such as short and vertical take-off and landing vehicles, cold gas dynamic spray processes, hot surface cooling mechanisms, and turbomachinery systems. The flow characteristics of a supersonic square jet discharging into the ambient and a supersonic jet impinging on a 45° inclined surface were experimentally investigated for nozzle-pressure-ratios (NPRs) of 4.8 and 5.9. Experimental measurements of impinging jets were acquired for nozzle-to-plate distances of 0.82Dj and 1.8Dj, where Dj is the jet hydraulic diameter. The velocity fields in the central plane of the jet were obtained using planar particle image velocimetry. The flow characteristics of the supersonic jets, including mean velocity and turbulent kinetic energy, were computed from the acquired two-dimensional two-component velocity vector fields, and statistical profiles were compared for different NPRs and nozzle-to-plate distances. For supersonic free jets, the acquired statistical results revealed the presence of multiple shock cells along the streamwise direction. Impinging jet measurements revealed the presence of shock cells in the vicinity of the nozzle outlet, oblique plate shocks near the impingement location, and several tail shocks along the streamwise direction. Spatial turbulent velocity cross correlations were calculated for various points located along the shear layers to investigate the characteristics of turbulent features, such as the shape, orientation, and integral length scales of the studied configurations. In addition, a proper orthogonal decomposition analysis was applied to the instantaneous velocity fields to identify the statistically dominant flow structures that play an important role in the flow field characteristics of supersonic free jets and supersonic impinging jets.
Layer-exchange crystallization for low-temperature (∼450 °C) formation of n-type tensile-strained Ge on insulator
Authors: Gao Hongmiao , Sadoh Taizoh
Published: October 2020

Layer-exchange crystallization of Ge using a group-V element has been investigated to develop a low-temperature (<500 °C) formation technique of n-type tensile-strained crystalline Ge on insulator. Here, the Sb of a group-V element is employed as a catalyst. Annealing (450 °C) of a-Ge (100 nm)/Sb (100 nm) bi-layer stacked structures generates layer-exchange crystallization. Namely, Ge and Sb layers exchange their positions, and Ge layers are crystallized on insulator substrates. However, Ge evaporation occurs during annealing, and a high concentration of Sb (∼20%) remains at the Ge/insulator interface. To solve these problems, the thickness reduction of Sb films and introduction of a-Ge thin under-layers are examined. By annealing (450 °C) a-Ge (100 nm)/Sb (50 nm)/a-Ge (5 nm) tri-layer structures, layer-exchange crystallization of Ge layers on insulator without Ge evaporation or Sb residue has been achieved. This enables formation of n-type tensile-strained (∼0.3%) Ge layers (free electron concentration: ∼5 × 1017 cm−3). Moreover, crystal orientation control of grown Ge films through the introduction of the diffusion barrier is examined. These results demonstrate the possibility of layer-exchange crystallization induced by a group-V element to realize functional thin-film devices for advanced electronics and photonics.
Platinum composition dependence of spin-orbit torque in (Fe0.8Mn0.2)1−xPtx single-layer ferromagnet
Authors: Luo Ziyan , Lu Ling , Xie Hang , Xu Yanjun , Chen Xin , Talapatra Abhishek , Adeyeye Adekunle Olusola , Hua Younan , Li Xiaomin , Wu Yihong
Published: October 2020

We have investigated the effect of the Pt composition on the spin–orbit torque in a (Fe0.8Mn0.2)1−xPtx single-layer ferromagnet. We observed that while the field-like torque decreases and even reverses sign with increasing the Pt composition, the damping-like torque increases monotonically and reaches 0.99 Oe/(1010 A/m2) in a single-layer (Fe0.8Mn0.2)0.52Pt0.48 film. The results corroborate the anomalous Hall effect and surface spin rotation model presented previously, and the relative ratio between the damping-like and field-like torques can be qualitatively understood as the relative phase change in spin-conserving and spin-flip scattering.
Analytical description of mixed ohmic and space-charge-limited conduction in single-carrier devices
Authors: Röhr Jason A. , MacKenzie Roderick C. I.
Published: October 2020

While space-charge-limited current measurements are often used to characterize charge-transport in relatively intrinsic, low-mobility semiconductors, it is currently difficult to characterize lightly or heavily doped semiconductors with this method. By combining the theories describing ohmic and space-charge-limited conduction, we derive a general analytical approach to extract the charge-carrier density, the conduction-band edge, and the drift components of the current density–voltage curves of a single-carrier device when the semiconductor is undoped, lightly doped, or heavily doped. The presented model covers the entire voltage range, i.e., both the low-voltage regime and the Mott–Gurney regime. We demonstrate that there is an upper limit to how doped a device must be before the current density–voltage curves are significantly affected, and we show that the background charge-carrier density must be considered to accurately model the drift component in the low-voltage regime, regardless of whether the device is doped or not. We expect that the final analytical expressions presented herein to be directly useful to experimentalists studying charge-transport in novel materials and devices.
Influence of disorder on superconductivity in the Si(111)-7×3-In surface
Authors: Wu Yanfu , Yao Gang , Qu Yueqiao , Wang Xutao , Liu Ningning , Duan Ming-Chao , Guan Dan-Dan , Wang Shiyong , Zheng Hao , Li Yao-Yi , Liu Canhua , Jia Jin-Feng
Published: October 2020

To uncover the critical effect of disorder on superconductivity, the ideal method is to visualize the microscopic crystalline deficiencies in real space while measuring the macroscopic superconducting properties. By using a self-developed multifunctional scanning tunneling microscope, we investigated the correlation between controllably introduced disorder and superconductivity in the Si(111)-7×3-In surface reconstruction. It is revealed that not only the density but also the spatial distribution of surface vacancies makes a significant influence on the diamagnetic response of the superconducting surface reconstruction. The higher density of vacancies uniformly dispersed on terraces results in a lower critical temperature and critical magnetic field, while the presence of grooves formed by aggregation of vacancies at step edges reduces the critical supercurrent and thus weakens the diamagnetic shielding effect remarkably.
Electron transport in iodide-capped core@shell PbTe@PbS colloidal nanocrystal solids
Authors: Miranti Retno , Septianto Ricky Dwi , Ibáñez Maria , Kovalenko Maksym V. , Matsushita Nobuhiro , Iwasa Yoshihiro , Bisri Satria Zulkarnaen
Published: October 2020

Research in the field of colloidal semiconductor nanocrystals (NCs) has progressed tremendously, mostly because of their exceptional optoelectronic properties. Core@shell NCs, in which one or more inorganic layers overcoat individual NCs, recently received significant attention due to their remarkable optical characteristics. Reduced Auger recombination, suppressed blinking, and enhanced carrier multiplication are among the merits of core@shell NCs. Despite their importance in device development, the influence of the shell and the surface modification of the core@shell NC assemblies on the charge carrier transport remains a pertinent research objective. Type-II PbTe@PbS core@shell NCs, in which exclusive electron transport was demonstrated, still exhibit instability of their electron transport. Here, we demonstrate the enhancement of electron transport and stability in PbTe@PbS core@shell NC assemblies using iodide as a surface passivating ligand. The combination of the PbS shelling and the use of the iodide ligand contributes to the addition of one mobile electron for each core@shell NC. Furthermore, both electron mobility and on/off current modulation ratio values of the core@shell NC field-effect transistor are steady with the usage of iodide. Excellent stability in these exclusively electron-transporting core@shell NCs paves the way for their utilization in electronic devices.
Development and study of high-power quantum-cascade lasers emitting at 4.5 – 4.6 μm
Authors: Dudelev V.V. , Mikhailov D.A. , Babichev A.V. , Savchenko G.M. , Losev S.N. , Kognovitskaya E.A. , Lyutetskii A.V. , Slipchenko S.O. , Pikhtin N.A. , Gladyshev A.G. , Denisov D.V. , Novikov I.I. , Karachinsky L.Ya. , Kuchinskii V.I. , Egorov A.Yu. , Sokolovskii G.S.
Published: October 2020

Quantum-cascade room-temperature 4.5 – 4.6 μm lasers with different numbers of quantum cascades are developed and studied. It is shown that losses at the metallised sidewalls of the ridge waveguide considerably increase the threshold current density. It is demonstrated that the current density needed to overcome the internal and outcoupling losses in lasers with 30 quantum cascades is an order of magnitude lower than in lasers with 15 quantum cascades.
Strong mutual increase in the efficiency of isotope-selective laser IR dissociation of molecules under nonequilibrium thermodynamic conditions of the compression shock under irradiation in a bimolecular mixture
Authors: Makarov G.N. , Petin A.N.
Published: October 2020

We have revealed a strong (by a factor of 2 to 5) mutual increase in the yield of IR molecular dissociation (by the example of CF2HCl and CF3Br) and a significant (by a factor of 1.5 to 3) lowering of dissociation thresholds in the nonequilibrium thermodynamic conditions of compression shock in the irradiation of the molecules by resonance IR laser radiation in the bimolecular mixture in comparison with their individual irradiation. This opens up the possibility to perform efficient isotope-selective IR dissociation of molecules at lower excitation energy densities (Φ⩽ 1.5 – 2.0 J cm−2) and thereby to improve the dissociation selectivity. This was demonstrated by the example of chlorine- and bromine-isotope selective dissociation of the specified molecules, which are characterised by quite small (less than 0.25 cm−1) isotope shifts in the IR vibrational absorption spectra excited by laser radiation. The enrichment coefficientsKenr(35Cl /37Cl) = 0.90 ± 0.05 in the residual CF2HCl gas andKenr(79Br /81Br) in the resultant Br2product are obtained when the CF2HCl : CF3Br = 1 : 1 molecular mixture and CF3Br molecules, respectively, are irradiated by the 9R(30) CO2laser line (frequency, 1084.635 cm−1) at an energy densityΦ≈ 1.3 J cm−2.
Radiation force and torque on a two-dimensional circular cross-section of a non-viscous eccentric layered compressible cylinder in acoustical standing waves
Authors: Mitri F G
Published: October 2020

The purpose of this study is to develop an analytical formalism and derive series expansions for the time-averaged force and torque exerted on a compound coated compressible liquid-like cylinder, insonified by acoustic standing waves having an arbitrary angle of incidence in the polar (transverse) plane. The host medium of wave propagation and the eccentric liquid-like cylinder are non-viscous. Numerical computations illustrate the theoretical analysis with particular emphases on the eccentricity of the cylinder, the angle of incidence and the dimensionless size parameters of the inner and coating cylindrical fluid materials. The method to derive the acoustical scattering, and radiation force and torque components conjointly uses modal matching with the addition theorem, which adequately account for the multiple wave interaction effects between the layer and core fluid materials. The results demonstrate that longitudinal and lateral radiation force components arise. Moreover, an axial radiation torque component is quantified and computed for the non-absorptive compound cylinder, arising from geometrical asymmetry considerations as the eccentricity increases. The computational results reveal the emergence of neutral, positive, and negative radiation force and torque depending on the size parameter of the cylinder, the eccentricity, and the angle of incidence of the insonifying field. Moreover, based on the law of energy conservation applied to scattering, numerical verification is accomplished by computing the extinction/scattering energy efficiency. The results may find some related applications in fluid dynamics, particle trapping, mixing and manipulation using acoustical standing waves.
Indium gallium nitride quantum dots: consequence of random alloy fluctuations for polarization entangled photon emission
Authors: Patra Saroj Kanta , Schulz Stefan
Published: October 2020

We analyze the potential of the c-plane InGaN/GaN quantum dots for polarization entangled photon emission by means of an atomistic many-body framework. Special attention is paid to the impact of random alloy fluctuations on the excitonic fine structure and the excitonic binding energy. Our calculations show that c-plane InGaN/GaN quantum dots are ideal candidates for high temperature entangled photon emission as long as the underlying C
3v
-symmetry is preserved. However, when assuming random alloy fluctuations in the dot, our atomistic calculations reveal that while the large excitonic binding energies are only slightly affected, the C
3v
symmetry is basically lost due to the alloy fluctuations. We find that this loss in symmetry significantly impacts the excitonic fine structure. The observed changes in fine structure and the accompanied light polarization characteristics have a detrimental effect for polarization entangled photon pair emission via the biexciton–exciton cascade. Here, we also discuss possible alternative schemes that benefit from the large excitonic binding energies, to enable non-classical light emission from c-plane InGaN/GaN quantum dots at elevated temperatures.
Variability of Aldosterone Measurements During Adrenal Venous Sampling for Primary Aldosteronism
Authors: Yozamp Nicholas , Hundemer Gregory L , Moussa Marwan , Underhill Johnathan , Fudim Tali , Sacks Barry , Vaidya Anand
Published: October 2020

BACKGROUND

Variability of aldosterone concentrations has been described in patients with primary aldosteronism.

METHODS

We performed a retrospective cohort study of 340 patients with primary aldosteronism who underwent adrenal venous sampling (AVS) at a tertiary referral center, 116 of whom also had a peripheral venous aldosterone measured hours before the procedure. AVS was performed by the same interventional radiologist using bilateral, simultaneous sampling, under unstimulated and then stimulated conditions, and each sample was obtained in triplicate. Main outcome measures were: (i) change in day of AVS venous aldosterone from pre-AVS to intra-AVS and (ii) variability of triplicate adrenal venous aldosterone concentrations during AVS.

RESULTS

Within an average duration of 131 minutes, 81% of patients had a decline in circulating aldosterone concentrations (relative decrease of 51% and median decrease of 7.0 ng/dl). More than a quarter (26%) of all patients had an inferior vena cava aldosterone of ≤5 ng/dl at AVS initiation. The mean coefficient of variation of triplicate adrenal aldosterone concentrations was 30% and 39%, in the left and right veins, respectively (corresponding to a percentage difference of 57% and 73%), resulting in lateralization discordance in up to 17% of patients if the lateralization index were calculated using only one unstimulated aldosterone-to-cortisol ratio rather than the average of triplicate measures.

CONCLUSIONS

Circulating aldosterone levels can reach nadirs conventionally considered incompatible with the primary aldosteronism diagnosis, and adrenal venous aldosterone concentrations exhibit acute variability that can confound AVS interpretation. A single venous aldosterone measurement lacks precision and reproducibility in primary aldosteronism.
Aseismic deformations perturb the stress state and trigger induced seismicity during injection experiments
Authors: Duboeuf Laure , De Barros Louis , Kakurina Maria , Guglielmi Yves , Cappa Frederic , Valley Benoit
Published: October 2020

Fluid injections can trigger seismicity even on faults that are not optimally oriented for reactivation, suggesting either sufficiently large fluid pressure or local stress perturbations. Understanding how stress field may be perturbed during fluid injections is crucial in assessing the risk of induced seismicity and the efficiency of deep fluid stimulation projects. Here, we focus on a series of in situ decametric experiments of fluid-induced seismicity, performed at 280 m depth in an underground gallery, while synchronously monitoring the fluid pressure and the activated fractures movements. During the injections, seismicity occurred on existing natural fractures and bedding planes that are misoriented to slip relative to the background stress state, which was determined from the joint inversion of downhole fluid pressure and mechanical displacements measured at the injection. We then compare this background stress with the one estimated from the inversion of earthquake focal mechanisms. We find significant differences in the orientation of the stress tensor components, thus highlighting local perturbations. After discussing the influence of the gallery, the pore pressure variation and the geology, we show that the significant stress perturbations induced by the aseismic deformation (which represents more than 96 per cent of the total deformation) trigger the seismic reactivation of fractures with different orientations.
The impact of inelastic self-interacting dark matter on the dark matter structure of a Milky Way halo
Authors: Chua Kun Ting Eddie , Dibert Karia , Vogelsberger Mark , Zavala Jesús
Published: October 2020

We study the effects of inelastic dark matter self-interactions on the internal structure of a simulated Milky Way (MW)-size halo. Self-interacting dark matter (SIDM) is an alternative to collisionless cold dark matter (CDM) which offers a unique solution to the problems encountered with CDM on sub-galactic scales. Although previous SIDM simulations have mainly considered elastic collisions, theoretical considerations motivate the existence of multi-state dark matter where transitions from the excited to the ground state are exothermic. In this work, we consider a self-interacting, two-state dark matter model with inelastic collisions, implemented in the Arepo code. We find that energy injection from inelastic self-interactions reduces the central density of the MW halo in a shorter timescale relative to the elastic scale, resulting in a larger core size. Inelastic collisions also isotropize the orbits, resulting in an overall lower velocity anisotropy for the inelastic MW halo. In the inner halo, the inelastic SIDM case (minor-to-major axis ratio s ≡ c/a ≈ 0.65) is more spherical than the CDM (s ≈ 0.4), but less spherical than the elastic SIDM case (s ≈ 0.75). The speed distribution f(v) of dark matter particles at the location of the Sun in the inelastic SIDM model shows a significant departure from the CDM model, with f(v) falling more steeply at high speeds. In addition, the velocity kicks imparted during inelastic collisions produce unbound high-speed particles with velocities up to 500 km s−1 throughout the halo. This implies that inelastic SIDM can potentially leave distinct signatures in direct detection experiments, relative to elastic SIDM and CDM.
Democratic Oversight and Political Direction of Chief Police Officers in England and Wales: Implications for Police Legitimacy
Authors: Shannon Ian
Published: October 2020

This article uses data from recent interviews with chief police officers in England and Wales to assess the connections between how chief police officers are overseen and given political direction and police legitimacy. The research found that governance changes started in 2011, particularly the election of police and crime commissioners, led to chief officers feeling more anxious, and the reforms reduced their operational independence. This may result in chief officers being less able to resist demands to encroach on civil liberties, prioritize the needs of the powerful over the marginalized, or to challenge policies that are likely to be ineffective or which neglect many peoples’ priorities. This endangers effective police leadership and legitimacy. Suggestions are made for consideration by policy makers, practitioners, and researchers to enhance police governance, leadership, and legitimacy. It is contended that the findings have implications for governance, leadership, and legitimacy in other countries and sectors.
The HOG Pathway Plays Different Roles in Conidia and Hyphae During Virulence of Alternaria alternata
Authors: Igbalajobi Olumuyiwa , Gao Jia , Fischer Reinhard
Published: October 2020

The black mold Alternaria alternata causes dramatic losses in agriculture due to postharvest colonization and mycotoxin formation and is a weak pathogen on living plants. Fungal signaling processes are crucial for successful colonization of a host plant. Because the mitogen-activated protein kinase HogA is important for the expression of stress-associated genes, we tested a ∆hogA-deletion strain for pathogenicity. When conidia were used as inoculum, the ∆hogA-deletion strain was largely impaired in colonizing tomato and apple. In comparison, hyphae as inoculum colonized the fruit very well. Hence, HogA appears to be important only in the initial stages of plant colonization. A similar difference between conidial inoculum and hyphal inoculum was observed on artificial medium in the presence of different stress agents. Whereas wild-type conidia adapted well to different stresses, the ∆hogA-deletion strain failed to grow under the same conditions. With hyphae as inoculum, the wild type and the ∆hogA-deletion strain grew in a very similar way. At the molecular level, we observed upregulation of several catalase (catA, -B, and -D) and superoxide dismutase (sodA, -B, and -E) genes in germlings but not in hyphae after exposure to 4 mM hydrogen peroxide. The upregulation required the high osmolarity glycerol (HOG) pathway. In contrast, in mycelia, catD, sodA, sodB, and sodE were upregulated upon stress in the absence of HogA. Several other stress-related genes behaved in a similar way.
Preharvest and Postharvest Applications of a Pomegranate Peel Extract to Control Citrus Fruit Decay During Storage and Shelf Life
Authors: Pangallo Sonia , Li Destri Nicosia Maria G. , Scibetta Silvia , Strano Maria C. , Cacciola Santa O. , Belgacem Imen , Agosteo Giovanni E. , Schena Leonardo
Published: October 2020

Green and blue molds are the most important postharvest diseases affecting citrus in storage. These diseases are commonly controlled with fungicides, but legislative restrictions, consumer concerns, and the development of resistant strains of the pathogens have increasingly led to the search for alternative methods of control. A pomegranate peel extract (PGE) was very effective in controlling Valencia orange and clementine postharvest rot under commercial conditions. After cold storage and 7 days of shelf life, the incidence of decay on oranges sprayed before harvest with PGE at 12, 6, and 3 g/liter was reduced by 78.9, 76.0, and 64.6%, respectively. Similarly, postharvest dipping treatments with PGE reduced rot by 90.2, 84.3, and 77.6%, respectively. Comparable levels of protection were also achieved on clementines. On both oranges and clementines, the extract provided a significantly higher level of protection compared with imazalil, a fungicide commonly used for postharvest treatments. The high level of efficacy and the consistent results on different fruit species (clementines and oranges) and with different application methods (preharvest and postharvest) were evidence of reliability and flexibility. PGE also showed a strong antimicrobial activity against fungi and bacteria, suggesting its possible use in sanitizers to reduce the microbial contamination of recirculated water in packinghouses. The results of the present study encourage the integration of conventional chemical fungicides and sanitizers with PGE to control citrus postharvest rot.
Leptosphaeria maculans Isolates Reveal Their Allele Frequency in Western Canada
Authors: Liu Fei , Zou Zhongwei , Peng Gary , Dilantha Fernando W. G.
Published: October 2020

Blackleg, caused by Leptosphaeria maculans, is a major disease of canola in Canada, Australia, and Europe. For effective deployment of resistant varieties and disease management, it is crucial to understand the population structure of L. maculans. In this study, we analyzed L. maculans isolates from commercial fields in western Canada from 2014 to 2016 for the presence and frequency of avirulence (Avr) genes. A total of 1,584 isolates were examined for the presence of Avr genes AvrLm1, AvrLm2, AvrLm3, AvrLm4, AvrLm6, AvrLm7, AvrLm9, AvrLepR1, AvrLepR2, and AvrLmS via a set of differential host genotypes carrying known resistance genes and a PCR assay. Several Avr genes showed a higher frequency in the pathogen population, such as AvrLm6 and AvrLm7, which were present in >90% of isolates, whereas AvrLm3, AvrLm9, and AvrLepR2 showed frequencies of <10%. A total of 189 races (different combinations of Avr genes) were detected, with Avr-2-4-6-7-S, Avr-1-4-6-7, and Avr-2-4-6-7 as the three predominant races. When the effect of crop rotation was assessed, only a 3-year rotation showed a significantly higher frequency of AvrLm2 relative to shorter rotations. This study provides the information for producers to select effective canola varieties for blackleg management and for breeders to deploy new R genes in disease resistance breeding in western Canada.
Spatial and Temporal Analysis ofPhytophthora megakaryaEpidemic in Newly Established Cacao Plantations
Authors: Ndoungué Djeumekop Minette Mireille , Ngo Bieng Marie-Ange , Ribeyre Fabienne , Bonnot Francois , Cilas Christian , Neema Claire , ten Hoopen Gerben Martijn
Published: October 2020

Studying spatial and temporal plant disease dynamics helps us to understand pathogen dispersal processes and improve disease control recommendations. In this study, three cacao plots devoid of primary inoculum of Phytophthora megakarya (causal agent of cacao black pod rot disease) upon establishment in 2006 were monitored for presence of disease on a weekly basis from 2009 to 2016. Ripley’s K(r) function, join count statistics, and Fisher’s Exact test were used to analyze spatial and temporal disease dynamics. Disease distribution maps showed aggregated disease patterns in all plots; however, for the years of disease onset, exogenous primary infections were mostly randomly distributed. The K(r) function confirmed these results indicating that inoculum generally disperses only over short distances. Moreover, significant positive spatial autocorrelations showed that diseased trees were often clustered up to a distance of 3 to 9 m. Temporal disease progression was low, meaning that endogenous inoculum failed to establish itself, which is partly explained by rigorous phytosanitation and partly by unfavorable microclimatic conditions for disease development. Because P. megakarya had difficulty establishing itself in the plots, proximity to already infected cacao plantations drove infection dynamics. Thus, isolation of newly established cacao plantations from infected ones and rigorous phytosanitation as a preventive strategy appears to be an effective approach to control cacao black pod rot disease for newly established cacao plantations.
Catastrophic Thinking and Pain Alleviation After Lower Extremity Surgery
Authors: Nunziato Carl , Fatehi Amirreza , Driscoll Matthew , Koenig Karl , Ring David , Laverty David
Published: October 2020

Objectives:

Requests for opioid pain medication more than a few weeks after surgery are associated with greater symptoms of depression and cognitive biases regarding pain such as worst-case thinking and fear of painful movement. We sought factors associated with patient desire for more opioid medication and satisfaction with pain alleviation at suture removal after lower extremity surgery.

Design:

Cross sectional study.

Setting:

Enrollment occurred at 1 of 4 orthopaedic offices in an urban setting.

Patients/Participants:

At suture removal after lower extremity surgery, 134 patients completed questionnaires measuring catastrophic thinking, ability to reach goals and continue normal activities in spite of pain, symptoms of depression, and magnitude of physical limitations.

Main Outcome Measurements:

Psychological factors associated with questionnaire-reported patient desire for another opioid prescription, satisfaction with postoperative pain alleviation, and the self-reported number of pills remaining from original opioid prescription.

Results:

In logistic regression, smoking and greater catastrophic thinking were independently associated with desire for opioid refill (R2 = 0.20). Lower satisfaction with pain alleviation was associated with greater catastrophic thinking (R2 = 0.19). The size of surgery (large vs. medium/small procedure) was not associated with pain alleviation or satisfaction with pain alleviation.

Conclusions:

The association between unhelpful cognitive bias regarding pain and request for more opioids reinforces the importance of diagnosing and addressing common misconceptions regarding pain in efforts to help people get comfortable.

Level of Evidence:

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
Improving Survival of Critical Care Patients With Coronavirus Disease 2019 in England: A National Cohort Study, March to June 2020*
Authors: Dennis John M. , McGovern Andrew P. , Vollmer Sebastian J. , Mateen Bilal A.
Published: October 2020

Objectives:

To measure temporal trends in survival over time in people with severe coronavirus disease 2019 requiring critical care (high dependency unit or ICU) management, and to assess whether temporal variation in mortality was explained by changes in patient demographics and comorbidity burden over time.

Design:

Retrospective observational cohort; based on data reported to the COVID-19 Hospitalisation in England Surveillance System. The primary outcome was in-hospital 30-day all-cause mortality. Unadjusted survival was estimated by calendar week of admission, and Cox proportional hazards models were used to estimate adjusted survival, controlling for age, sex, ethnicity, major comorbidities, and geographical region.

Setting:

One hundred eight English critical care units.

Patients:

All adult (18 yr +) coronavirus disease 2019 specific critical care admissions between March 1, 2020, and June 27, 2020.

Interventions:

Not applicable.

Measurements and Main Results:

Twenty-one thousand eighty-two critical care patients (high dependency unit n = 15,367; ICU n = 5,715) were included. Unadjusted survival at 30 days was lowest for people admitted in late March in both high dependency unit (71.6% survival) and ICU (58.0% survival). By the end of June, survival had improved to 92.7% in high dependency unit and 80.4% in ICU. Improvements in survival remained after adjustment for patient characteristics (age, sex, ethnicity, and major comorbidities) and geographical region.

Conclusions:

There has been a substantial improvement in survival amongst people admitted to critical care with coronavirus disease 2019 in England, with markedly higher survival rates in people admitted in May and June compared with those admitted in March and April. Our analysis suggests this improvement is not due to temporal changes in the age, sex, ethnicity, or major comorbidity burden of admitted patients.
A Pilot Program Assessing Bronchoscopy Training and Program Initiation in a Low-income Country
Authors: Siddharthan Trishul , Jackson Peter , Argento A. Christine , Sachdeva Ashutosh , Yarmus Lonny , Alupo Patricia , Kirenga Bruce , Woordria William , Lee Hans J.
Published: October 2020

Background:

Flexible bronchoscopy is an essential procedure for the evaluation and management of the pulmonary disease. However, this technology and related training is not available in many low-middle income countries (LMICs). We conducted a pilot training program for flexible bronchoscopy in Uganda.

Methods:

A multimodal curriculum was developed with pulmonologists from Uganda and the United States. The training included an online distance learning management system for video content, simulation, just-in-time training, and deliberate practice via clinical proctoring. Procedural standards and a de novo bronchoscopy suite were concurrently developed. Competency was assessed using the Bronchoscopic Skills and Tasks Assessment Tool written examination and the Ontario Bronchoscopy Assessment Tool.

Results:

We trained 3 pulmonary physicians with no prior experience in flexible bronchoscopy. Three bronchoscopies with bronchoalveolar lavage were performed during the training and an additional 11 cases were performed posttraining. All 3 Ugandan physicians had an increase in their written Bronchoscopic Skills and Tasks Assessment Tool and Ontario Bronchoscopy Assessment Tool in the competent range (P<0.05). All bronchoscopies were successfully completed, adequate samples were obtained, and there were no procedure-related complications.

Conclusion:

Bronchoscopy implementation in LMICs is feasible, but requires competency-based training. Further studies are needed to validate this curriculum in LMICs, including the use of this type of curriculum for more complicated bronchoscopic procedures.
Obesity and immune status in children
Authors: Fang Xingyuan , Henao-Mejia Jorge , Henrickson Sarah E.
Published: October 2020

Purpose of review

Childhood obesity, with persistent chronic inflammation, is a worldwide epidemic. Obesity causes dysregulation throughout the immune system, affecting the balance and levels of cytokines, adipokines, and innate and adaptive immune cells. The present review focuses on the impact of obesity on immune function in children: altering the baseline activation state of immune cells and affecting the ability of the host to combat pathogens and malignancy and respond appropriately to vaccination.

Recent findings

Obesity causes dysregulation of the immune system. Single-cell RNA-sequencing of adipose tissue and resident immune cells is quantifying the impact of obesity on the frequency of immune cell subsets and their states. The system-wide alterations in immune function in obesity are most evident upon perturbation, including the response to infection (e.g. increased risk of severe COVID-19 in the ongoing pandemic), vaccination, and malignancy. However, mechanistic research in pediatric obesity is limited and this impacts our ability to care for these children.

We must better understand baseline and perturbed immune health in obese children to determine how to account for altered frequency and function of humoral and cellular immune components in acute infection, during vaccine design and when considering therapeutic options for this complex, medically vulnerable group.
Coccygodynia Due to a Sacrococcygeal Anomaly
Authors: García Sánchez Paula , de Ceano Vivas la Calle María , Martín Sánchez Julia , Molina Gutiérrez Miguel Ángel , Pérez Vigara Ana , Martínez Martínez Leopoldo
Published: October 2020

We report a case of an uncommon sacrococcygeal anomaly in a healthy girl initially presenting to the emergency department with coccygodynia and a past history of longstanding constipation. The clinical evolution was satisfactory once the bony anomaly was removed (coccygectomy). This unusual case exemplifies the importance of the medical history and physical examination to make an accurate diagnosis. An inadequate intervention may result in persistent pain, worsening longstanding constipation, and psychosocial and medical consequences.
Diagnosis and Treatment of Headache in a Pediatric Emergency Department
Authors: Costa Francisca M. , Ferreira Inês P. , Mascarenhas Inês F. , Alves Cláudio F. , Bento Vanda A. , Loureiro Helena C.
Published: October 2020

Objectives

The aims of the study were (1) to analyze the etiology and clinical management of headaches in children in the emergency department and (2) to analyze the treatment used in children diagnosed with headaches and with migraines.

Methods

Retrospective study of all the patients who were admitted to the pediatric emergency department of Hospital Professor Doutor Fernando Fonseca, Lisbon, in 2014, with a chief complaint of headaches or the primary discharge diagnosis was headache/migraine.

Results

Headache related cases represented 3.8% of all the visits, a total of 2354 subjects. The median age was 10 years and 52.6% were female. The most frequent diagnoses were as follow: headaches (21.3%), upper respiratory infections (18.4%), and migraines (6.1%). There were 4 cases of meningitis, 6,5% of all patients underwent computed tomography which was mostly requested in school-age children and adolescents. The average time from the first medical observation until discharge was 85 minutes. Fifty-five percent did not take any pain relief medication, 17.2% took acetaminophen, and 11.1% took ibuprofen. Patients who received ondansetron had less revisits (P = 0.000). Subjects with mild-moderate pain treated with acetaminophen or no medication had more revisits (P = 0.000).

Conclusions

Secondary benign headaches were the most common and very rarely headache as a symptom was associated with life-threatening situations. Antiemetics seem to be efficient ally in the treatment of primary headaches, but it is important to consider alternative pharmacological regimes in patients who present with higher pain scores.
Wheelchair Athlete Concussion Baseline Data
Authors: Harper Michael W. , Lee Jonathan , Sherman Katherine A. , Uihlein Michael Joseph , Lee Kenneth Kyung Keun
Published: October 2020

Objective

The aim of the study was to investigate whether a disabled athlete’s underlying disability and concussion history impact the score on baseline testing from a disability modified Graded Symptoms Checklist, Standardized Assessment of Concussion, and Wheelchair Error Scoring System.

Study Design

This is a retrospective chart review of the 81 veteran wheelchair sports athletes who had baseline concussion evaluations. Demographic data including qualifying disability for the National Veterans Wheelchair Games, scores from the modified Graded Symptoms Checklist, Standardized Assessment of Concussion, and Wheelchair Error Scoring System were analyzed.

Results

Forty-three percent of wheelchair athletes reported a history of a concussion. Individuals with a history of a concussion displayed more symptoms on the modified Graded Symptoms Checklist (38.8vs.24.71,P= 0.0378) as did those who had a qualifying disability in the brain disorder category (54.87vs.amputees 24.07 and spinal cord disorders 24.9,P= 0.0015). There was no difference in Standardized Assessment of Concussion examination or Wheelchair Error Scoring System scores based on concussion history or qualifying disability.

Conclusions

Baseline symptom scores from a modified Graded Symptoms Checklist were higher in participants with a history of concussion, independent of their underlying disability, and higher if the athlete’s disability was a brain disorder including multiple sclerosis and cerebral vascular accident. Scores on the Standardized Assessment of Concussion examination and Wheelchair Error Scoring System were not affected by the athlete’s disability or concussion history. Baseline testing is integral for disabled athletes, especially those with underlying brain disorders and history of concussion.
Hardness of Herd Immunity and Success Probability of Quarantine Measures: A Branching Process Approach
Authors: Nath Sujit Kumar
Published: October 2020

Herd immunity refers to the collective resistance of a population against the spreading of an infection as an epidemic. Understanding the dependencies of herd immunity on various epidemiological parameters is of immense importance for strategizing control measures against an infection in a population. Using an age-dependent branching process model of infection propagation, we obtain interesting functional dependencies of herd immunity on the incubation period of the contagion, contact rate, and the probability of disease transmission from an infected to a susceptible individual. We show that herd immunity is difficult to achieve in case of a high incubation period of the contagion. We derive a method to quantify the success probabilities of quarantine measures to mitigate infection from a population, before achieving herd immunity. We provide a mechanistic derivation of the distribution of generation time from basic principles, which is of central importance to estimate the reproduction number R0, but has been assumed in an ad hoc manner in epidemiological studies, by far. This derivation of the generation time distribution has the generality to be applied in the study of many other age-dependent branching processes, such as the growth of bacterial colonies, various problems in evolutionary and population biology etc.
Extending the range of symptoms in a Bayesian Network for the Predictive Diagnosis of COVID-19
Authors: Butcher Rachel , Fenton Norman
Published: October 2020

Emerging digital technologies have taken an unprecedented position at the forefront of COVID-19 management. This paper extends a previous Bayesian network designed to predict the probability of COVID-19 infection, based on a patient’s profile. The structure and prior probabilities have been amalgamated from the knowledge of peer-reviewed articles. The network accounts for demographics, behaviours and symptoms, and can mathematically identify multivariate combinations with the highest risk. Potential applications include patient triage in healthcare systems or embedded software for contact-tracing apps. Specifically, this paper extends the set of symptoms that are a marker for COVID-19 infection and the differential diagnosis of other conditions with similar presentations.