bluuebunny/crossref_metadata_2025 huggingface dataset:
The Initial Weight Estimation of New Aircraft Design Solutions
Authors: Kretov Anatolii
Published: July 2020

The work is devoted to the rapid assessment of the weight of the aircraft and its design. This problem occurs when creating new aircraft or in the process of constructive improvement of existing ones. To determine the mass of the entire aircraft, the method of “mass change coefficients” (growth coefficients) is used, which is based on the equation of the existence of the aircraft. To analyze the mass of initial design changes, the Komarov weight formula based on the concept of “load-carrying factor” is used. The article considers a numerical example of estimating changes in the mass of an aircraft due to the use of composite materials in the fuselage structure.
Estimation Method of Pollutant Emissions in Certain Aircraft Flight
Authors: Song H , Yue L , Han X , Wei Z
Published: July 2020

This paper intends to calculate the emissions of pollutants during the route flight quantitatively. In this paper, the flight dynamics model of the climb, cruise and descent phases are established respectively. Then, the pollutant emission estimation model of the aircraft is established based on the ICAO LTO model and the benchmark emissions data of engine manufacturers. Take certain civil aviation aircraft into account, a typical route is simulated, then the emissions of various pollutants at different flight stages are calculated and analyzed. Finally, several typical cruise strategies are selected for further comparative analysis. The results show that CO2 and NOX are the main pollutants during route flight. In addition, the pollutant emissions during the cruise phase are the highest, and the pollutant emissions during route flight can be effectively reduced by choosing the appropriate cruise strategy. The research results can be used to quantify and analyze the impact of flight performance optimization on civil aviation energy conservation and emission reduction, so as to better satisfy the requirements of green operations while ensuring flight safety.
Research on Reliability Evaluation Method of Multi - rotor UAV Airborne Controller
Authors: Zhang Gaowei , Dong Xiaoqun
Published: July 2020

The reliability of multi-rotor Unmanned Aerial Vehicle (UAV) and the airborne controller is one of the research focus in UAV filed. In order to evaluate the reliability life of multi - rotor UAV airborne controller, this paper studied the basic principle of reliability life qualification firstly. Secondly, this paper focused on the analysis of the task profile of the multi-rotor UAV airborne controller, as well as the temperature, electricity and vibration stress of each task stage. Thirdly, the test profiles and specific parameters of each stress in the reliability test were determined. Lastly, some tests were done to verify the method proposed in the article. The reliability evaluation method of the multi - rotor UAV airborne controller proposed in this paper can be used in the practical application of UAV enterprises. It has good guiding significance.
Sounding Rockets Scattering Factors and their Influence on Motion Accuracy
Authors: Zosimovych Nickolay
Published: July 2020

The increase of sounding rocket active part of trajectory compared to the “normal” can be due to the launches of ballistic flying vehicle for the maximum specified range. In this case, rockets should use propulsion systems with a relatively low fuel specific impulse. This effect also occurs in case of implementation of minimum scattering programs during launches at intermediate ranges (between the minimum and maximum mission ranges). In proposed research was developed methods for analysing the influencing of ballistic and navigation support the uncertain factors on the accuracy of sounding rocket motion with an extended active part of trajectory and was given a relevant assessment to the contribution of each component in relation to specific cases of their occurrence.
Research on Design Method of High Speed and High Dynamic Pressure Separation Structure
Authors: Jian Xu , Siyi Fan
Published: July 2020

The inter-stage separation scheme has always been the focus and difficulty of low-altitude high-speed aircraft design. The separation reliability of low altitude high-speed aircraft is required to be higher. Experts and scholars have carried out design research on different forms of separation schemes. In this paper, two typical kind of inter-stage separation schemes are introduced. For aircraft A, a point cold separation scheme is adopted, which is connected by four explosive bolts, and two piston push rods provide separation impulse. For aircraft B, exhaust ports are opened on both sides of the rear of the transition section. The tail section is equipped with four “X” full-motion rudders for flight control. In addition, two horizontal stabilizers were added to improve stability. Based on the comparison and analysis of different inter-stage separation schemes for The separation reliability of low altitude high-speed aircraft is required to be higher. Experts and scholars have carried out design research on different forms of separation schemes. two different types of aircraft A and aircraft B, a new high reliability interstage separation scheme is proposed, the feasibility of the scheme is verified by simulation analysis, and the design of the stage separation structure under high dynamic pressure and high speed with compact layout is realized.
Study on the Computation Method for the Generalized Force and Mass of Flexible Aerial Rudder in Space Vehicle
Authors: Peng-fei Guo , Jian-hui Wu , Wei-qiang Zhang , Yong Zhang , Yang Yang
Published: July 2020

Aerial rudders are significant actuators in the spacecraft control systems and are responsible for the stability and control of different motions such as pitching, yawing and rolling around mass center. With the development of new generation of space vehicles, high speed flight demonstration, light and thin aerial rudders with large span-chord ratio have been widely used. In the design of control strategies in pitching, yawing and rolling channels and control feedback loop parameters, the influence caused by aerial rudder elastic deformation should be considered particularly. In this paper, elastic motion equations of the spacecraft flexible rudder are studied firstly. Then, according to the modal vibration features, aerodynamic force derivative distribution characteristics and generalized force expressions, the rudder station division and computation method of generalized rudder aerodynamic force derivatives are proposed in the pitching, yawing and rolling channels based on the computational fluid dynamics simulation. By comparison the results of the proposed method with these of the traditional computation methods, the accuracy and validity of the proposed method are verified which can provide considerable references and basis in the control design of flexible rudder in the spacecraft.
Research on the Operating Mechanicals of the Helicopter Robot Pilot
Authors: Jin Zibo , Li Daochun , Wang Ziyu
Published: July 2020

The requirements for the quantity and quality of pilots are getting more and more demanding. The helicopter robot pilot was put forward as a new autonomous driving scheme which can achieve fast switch between pilot driving and autonomous driving without modifying helicopters. The overall design of the robot was determined and the actuators of the robot was demonstrated in detail according to the handling characteristics of helicopter manipulation mechanism. Based on the detailed design scheme, the robot pilot was processed and assembled. In order to test the control performance of the robot pilot, the robot was installed in the flight simulator to carry out helicopter flight simulations. The test results illustrated that the robot pilot is able to accomplish basic flight control of helicopter.
Research on the Influence and Control of Obstacles Around the DVOR
Authors: Ye Jiaquan , Li Yuankai , Liang Fei , Xu Jian
Published: July 2020

This paper studies the influence and control of obstacles around the DVOR and propose the control methods by combining the standards and theories. First of all, according the relevant technical standards of GB6364-2013 and MH/T4003.1-2014 to control the height of obstacles, then perform modeling and simulation and analyze whether obstacles will affect the signal coverage of DVOR. In order to prevent attenuation, this paper strictly controls the height of obstacles based on the theory of signal propagation, the Fresnel Zone principle and Diffraction theory. The results show that technical standards are the minimum operating requirements when used. When we set the height of obstacles only reply on the technical standards, the signal will not fully meet the signal coverage of requirements. It is necessary to analyze and control the obstacles deeply according to actual condition.
The Research on Redundant Design in Civil Aircraft Design
Authors: Cheng Bing
Published: July 2020

This article explores the redundant design in the design of civil aircraft. It’s based on the meaning of giving redundancy beyond the basic needs to the parts or the products by redundant design. And this article also conducts targeted research on several typical redundant design methods such as redundant design in sketch, redundant design steps in part, integrated design of parts, redundant parts in assembly and redundant assembly of the civil aircraft. The redundant design formulas corresponding to different design methods are obtained by analyzing specific design examples. It is found in the research that redundant designs and components are also effective ways to optimize the design of the structure and to pre-solve a series of problems that may appear in subsequent stages. Moreover, the realizations of the requirements are compared between the step-by-step redundant design and the integrated redundant design. And it is found that the step-by-step redundant design is a better design method.
Graphene-diamond junction photoemission microscopy and electronic interactions
Authors: Wan Gary , Panditharatne Sanjeevani , Fox Neil A , Cattelan Mattia
Published: July 2020

Polycrystalline graphene was transferred onto differently terminated epitaxial layers of boron-doped diamond deposited onto single crystal substrates. Chemical and electronic characterisation was performed using energy-filtered photoemission electron microscopy and angle-resolved photoemission spectroscopy. Electronic interaction between the diamond and graphene was observed, where doping of the graphene on the hydrogen and oxygen terminated diamond was n-doping of 250 meV and 0 meV respectively. We found that the wide window of achievable graphene doping is effectively determined by the diamond surface dipole, easily tuneable with a varying surface functionalisation. A Schottky junction using the graphene-diamond structure was clearly observed and shown to reduce downward band bending of the hydrogen terminated diamond, producing a Schottky barrier height of 330 meV.
Structural and optical properties of sol-gel synthesized h-MoO3 nanorods treated by gamma radiation
Authors: Sen Sapan Kumar , Mortuza Abdul Al , Manir M S , Pervez M F , Hossain S M A I , Shah Alam Md , Haque M A S , Matin M A , Hakim M A , Huda Ain-ul
Published: July 2020

High energy external gamma radiation has always an impact on semiconductor material by altering its physico-chemical properties. In this paper, the effect of gamma-radiation is observed on sol-gel synthesized metastable h-MoO3 nanorods with absorbed dose variation. The irradiated sample shows a remarkable change in their structural parameters such as average crystallite size decreased, strain, and dislocation density increased and so on are confirmed from the x-ray diffraction (XRD). Functional groups and the corresponding vibration and stretching are analyzed from the Fourier transform infrared spectroscopy (FTIR). The change in surface morphology is observed from the field emission scanning electron microscopy (FESEM) image and found no remarkable change. However, the optical band gap decreases with increasing absorbed dose and calculated 2.84 eV, 2.82 eV, 2.80 eV and 2.77 eV for 0 kGy, 40 kGy, 80 kGy, and 120 kGy, respectively by Kubelka-Munk (K-M) function from the diffuse reflectance data of UV–vis-NIR spectrophotometer.
Efficient dynamic variation graphs
Authors: Eizenga Jordan M , Novak Adam M , Kobayashi Emily , Villani Flavia , Cisar Cecilia , Heumos Simon , Hickey Glenn , Colonna Vincenza , Paten Benedict , Garrison Erik
Published: July 2020

Motivation

Pangenomics is a growing field within computational genomics. Many pangenomic analyses use bidirected sequence graphs as their core data model. However, implementing and correctly using this data model can be difficult, and the scale of pangenomic datasets can be challenging to work at. These challenges have impeded progress in this field.

Results

Here, we present a stack of two C++ libraries, libbdsg and libhandlegraph, which use a simple, field-proven interface, designed to expose elementary features of these graphs while preventing common graph manipulation mistakes. The libraries also provide a Python binding. Using a diverse collection of pangenome graphs, we demonstrate that these tools allow for efficient construction and manipulation of large genome graphs with dense variation. For instance, the speed and memory usage are up to an order of magnitude better than the prior graph implementation in the VG toolkit, which has now transitioned to using libbdsg’s implementations.

Availability and implementation

libhandlegraph and libbdsg are available under an MIT License from https://github.com/vgteam/libhandlegraph and https://github.com/vgteam/libbdsg.
A developmental approach expanding the knowledge of inflorescence diversity in subtribe Eleusininae (Chloridoideae: Poaceae)
Authors: Muchut Sebastián E , Pilatti Vanesa , Reutemann Andrea G , Vegetti Abelardo C , Reinheimer Renata
Published: July 2020

Subtribe Eleusininae (Chloridoideae, Poaceae) comprise 237 species with little morphological diversity in inflorescence structure. This diversity may be explained by an evolution from complex (pyramidal, highly branched) to simpler (digitate, barely branched) morphologies. However, only mature specimens have been studied; the developmental analyses of the inflorescences are rare. We analysed the inflorescence, spikelet and flower development of 17 species of Eleusininae using scanning electron microscopy. In the early stages of the transition to flowering of the studied species, the inflorescence meristem elongates initiating primary branches acropetally. The differentiation of these branches along the main axis is either basipetal or amphipetal. Although the initiation of secondary branches along primary branches may be acropetal or amphipetal, their differentiation follows an amphipetal direction. The florets in spikelets are initiated acropetally. We found abnormal orientation of stamens and gynoecium in florets of Leptochloa chloridiformis. The analysis of the ontogeny has enriched current knowledge of inflorescences in the subtribe. In addition, the developmental patterns revealed the existence of more than one developmental pattern leading to similar mature inflorescence forms. The results will support future efforts on postulating trends of developmental patterns across Poaceae.
Reduced Susceptibility of Mycobacterium tuberculosis to Bedaquiline During Antituberculosis Treatment and Its Correlation With Clinical Outcomes in China
Authors: Liu Yuhong , Gao Mengqiu , Du Jian , Wang Lu , Gao Jingtao , Shu Wei , Wang Yufeng , Xue Zhongtan , Li Liang , Pang Yu
Published: July 2020

Background

We aimed to assess the proportion of multidrug-resistant tuberculosis (MDR-TB) cases with initial bedaquiline (BDQ) resistance, monitor the dynamics of BDQ susceptibility of Mycobacterium tuberculosis isolates during therapy, and correlate susceptibility with MDR-TB patient clinical outcomes in China.

Methods

A retrospective, cohort study of MDR-TB patients was conducted, with positive cultures collected from cases at 13 sites. Patients with nontuberculous mycobacterial infection during anti-TB therapy were excluded. BDQ minimal inhibitory concentrations (MICs) were determined using a 7H9 Middlebrook broth-based microdilution method. Mutations that conferred BDQ resistance were detected via Sanger sequencing.

Results

A total of 277 patients receiving BDQ treatment were studied, with BDQ resistance noted in isolates from 2.2% (6/277) of MDR-TB cases, sputum conversion observed in 5 cases, and culture conversion observed in 138 cases within 2 weeks. Another 15 and 30 isolates were excluded from final analysis due to failures in obtaining subcultures and serial isolates, respectively. Of 94 cases that yielded serial isolates, 11 exhibited reduced BDQ susceptibility, while 3 of 5 cases with acquired resistance failed to culture-convert. Sequence analysis revealed that 6 of 11 BDQ-resistant isolates harbored Rv0678 mutations; no mutations were detected in 3 other BDQ resistance-associated genes. No significant intergroup difference in culture conversion time was observed.

Conclusions

MDR-TB patients in China exhibited a low initial BDQ resistance rate. MDR-TB cases with acquired BDQ resistance were at greater risk of treatment failure relative to initially BDQ-resistant cases. Rv0678 mutations accounted for BDQ resistance in this cohort.
Lemuria: A Novel Future Crop Prediction Algorithm Using Data Mining
Authors: Tamil Selvi M , Jaison B
Published: July 2020

Agriculture exhibitions an important role in the progression and enlargement of the economy of any country. Prediction of crop yield will be useful for farmers, but it is difficult to predict crop yield because of the climatic factors such as rainfall, soil factors and so on. To tackle these issues, we are implementing a novel algorithm called Lemuria by applying data mining in agriculture especially for crop yield analysis and prediction. This novel algorithm is the hybridization of classifiers for pre-training, training and testing: deep belief network for feature learning, k-means clustering together with particle swarm optimization (PSO) to get the global solution as well as naïve Bayes clustering with PSO for testing. The performance of the Lemuria algorithm is evaluated in Python, which provides an accuracy of 97.74% for crop prediction by considering the rainfall dataset and also stated that this gives the optimum results in comparison with the existing methodologies.
A bibliographical imbroglio: Books 1 and 2 of Couperin’s Pièces de clavecin
Authors: Herlin Denis
Published: July 2020

During the preparation of a new critical edition of Couperin’s keyboard music for Bärenreiter (Book 1, 2016; Book 2, 2018), I examined 72 exemplars of the first book and 52 of the second, listed variously in RISM and in French regional library catalogues. This large number of surviving exemplars is testimony to the exceptionally wide diffusion of these publications and also their remarkable influence, even though Couperin’s music was never taken up by publishers outside France. Careful collation of these exemplars has allowed the identification of no fewer than 16 impressions of Book 1 and 15 impressions of Book 2. The existence of so many variant versions of the two books raises questions about the nature of the corrections made at various times by the composer himself; about the process by which these volumes were assembled prior to sale; and, more broadly, about how the retailing of sheet music was organized.
Characteristics and predictors of hospitalization and death in the first 11 122 cases with a positive RT-PCR test for SARS-CoV-2 in Denmark: a nationwide cohort
Authors: Reilev Mette , Kristensen Kasper Bruun , Pottegård Anton , Lund Lars Christian , Hallas Jesper , Ernst Martin Thomsen , Christiansen Christian Fynbo , Sørensen Henrik Toft , Johansen Nanna Borup , Brun Nikolai Constantin , Voldstedlund Marianne , Støvring Henrik , Thomsen Marianne Kragh , Christensen Steffen , Gubbels Sophie , Krause Tyra Grove , Mølbak Kåre , Thomsen Reimar Wernich
Published: July 2020

Background

Population-level knowledge on individuals at high risk of severe and fatal coronavirus disease 2019 (COVID-19) is urgently needed to inform targeted protection strategies in the general population.

Methods

We examined characteristics and predictors of hospitalization and death in a nationwide cohort of all Danish individuals tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from 27 February 2020 until 19 May 2020.

Results

We identified 11 122 SARS-CoV-2 polymerase chain reaction-positive cases of whom 80% were community-managed and 20% were hospitalized. Thirty-day all-cause mortality was 5.2%. Age was strongly associated with fatal disease {odds ratio [OR] 15 [95% confidence interval (CI): 9–26] for 70–79 years, increasing to OR 90 (95% CI: 50–162) for ≥90 years, when compared with cases aged 50–59 years and adjusted for sex and number of co-morbidities}. Similarly, the number of co-morbidities was associated with fatal disease [OR 5.2 (95% CI: 3.4–8.0), for cases with at least four co-morbidities vs no co-morbidities] and 79% of fatal cases had at least two co-morbidities. Most major chronic diseases were associated with hospitalization, with ORs ranging from 1.3–1.4 (e.g. stroke, ischaemic heart disease) to 2.6–3.4 (e.g. heart failure, hospital-diagnosed kidney disease, organ transplantation) and with mortality with ORs ranging from 1.1–1.3 (e.g. ischaemic heart disease, hypertension) to 2.5–3.2 (e.g. major psychiatric disorder, organ transplantation). In the absence of co-morbidities, mortality was <5% in persons aged ≤80 years.

Conclusions

In this nationwide population-based COVID-19 study, increasing age and multimorbidity were strongly associated with hospitalization and death. In the absence of co-morbidities, the mortality was, however, <5% until the age of 80 years.
Journey from the West: first record of the Indian Ocean pilumnid crab Pilumnopeus convexus (Maccagno, 1936) (Decapoda: Brachyura: Pilumnidae) in Hong Kong
Authors: Wong Kingsley J H , Tsang Ling Ming , Ng Peter K L
Published: July 2020

The pilumnid crab Pilumnopeus convexus (Maccagno, 1936), native to the Arabian Sea and western Indian Ocean, has been discovered among intertidal fouling communities along shores of Hong Kong. The species was first discovered in 2011 and is believed to have become established by around 2016. Material from local sites was compared with specimens from Iran and Pakistan, and the identification was supported by molecular analyses using mtDNA COI gene sequences. This species is not yet known from East and Southeast Asia, and was probably transported to Hong Kong by international maritime shipping, likely in the ballast water or on the hulls of ships, and subsequently survived as a non-indigenous species (NIS). This represents the first case of west-to-east invasion of brachyuran crabs from the Indian Ocean reaching sub-tropical East Asia. Past studies on the local intertidal fauna, and documentations of NIS, are briefly discussed.
Construction and validation of a prognostic nomogram for primary vulvar melanoma: a SEER population-based study
Authors: Zhou Hongyu , Zou Xuan , Li Haoran , Chen Lihua , Cheng Xi
Published: July 2020

Background

Primary vulvar melanoma was an aggressive and poorly understood gynecological tumor. Unlike cutaneous melanoma, the incidence of vulvar melanoma was low but the survival was poor. There were no standard staging system and no census on treatment strategies of vulvar melanoma. Therefore, we aimed to conduct and validate a comprehensive prognostic model for predicting overall survival of vulvar melanoma and provide guidance for clinical management.

Methods

Patients diagnosed with vulvar melanoma between year 2004 and 2015 from Surveillance, Epidemiology, and End Result (SEER) database were randomized to training cohort and validation cohort. Multivariate survival analysis was performed to screen for independent factors of survival. A nomogram was established to predict overall survival of vulvar melanoma. Receiver operating characteristic curve and calibration plot were performed to verify the discrimination and accuracy of the model. The decision curve analysis was performed to verify the clinical applicability of the model.

Results

Total 737 patients with vulvar melanoma were randomized to the training cohort (n = 517) and the validation cohort (n = 220). Nomogram including age, race, tumor site, depth of tumor invasion, lymph node status, distant metastasis, tumor size, surgery, chemotherapy and radiotherapy was established and validated. The c-indexes for SEER stage, American Joint Committee on Cancer stage and this model were 0.561, 0.635 and 0.826, respectively. The high-risk group scored by this model had worse survival than the low-risk group (P < 0.001). Decision curve analysis revealed this model was superior in predicting survival.

Conclusions

Our model was deemed to be a useful tool for predicting overall survival of vulvar melanoma with good discrimination and clinical applicability. We hoped this model would assist gynecologists in clinical decision and management of patients diagnosed with vulvar melanoma.
Population turnover promotes fungal stability in a semi-arid grassland under precipitation shifts
Authors: Wang Nannan , Li Lei , Zhang Bingwei , Chen Shiping , Sun Wei , Luo Yukun , Dong Kuanhu , Han Xingguo , Huang Jianhui , Xu Xiaofeng , Wang Changhui
Published: July 2020

Aims

Bacteria and fungi are two primary groups of soil microbes, and their stability determines the persistence of microbial functions in response to a changing environment. Recent studies reported higher fungal than bacterial stability under precipitation alteration, the underlying mechanisms, however, remain elusive.

Methods

A 3-year precipitation manipulation experiment in a semi-arid grassland was used to compare the bacterial and fungal diversities, including alpha diversity, beta diversity and microbial community composition turnover, in response to precipitation manipulations. A framework is proposed to understand the stability properties of bacteria and fungi under precipitation alteration. We conceived a diagrammatic valley to illustrate microbial stability with the depth representing resistance and the width ecological resilience.

Important Findings

We found that ±60% in precipitation significantly reduced the richness and increased the evenness of bacteria but had trivial impacts on fungi. Precipitation alteration yielded stronger impacts on the variation in alpha diversity of bacteria than fungi, suggesting that the bacterial community is more sensitive to water stress than the fungal community. Moreover, fungi had wider composition turnover than that of bacteria, indicating higher composition variation of fungi than bacteria. The population turnover of fungi, reflected by composition variation, coefficient variation of diversity index and composition turnover, was larger than that of bacteria at both temporal and spatial scales, indicating the population turnover promotes fungal stability. The higher stability of fungal community in tolerating water stress is analogous to a ball in a wide valley that swing substantially but remain close to its steady state; while the lower stability of bacteria community is analogous to a ball that swings slightly but stay far away from its steady state. Our finding that the fungal community had higher stability than bacterial community in a semi-arid grassland might be applicable to other biomes.
Linking the spatiotemporal variation of litterfall to standing vegetation biomass in Brazilian savannas
Authors: Costa Alan N , Souza Jeane R , Alves Karyne M , Penna-Oliveira Anderson , Paula-Silva Geisciele , Becker Ingrid S , Marinho-Vieira Kelly , Bonfim Ana L , Bartimachi Alessandra , Vieira-Neto Ernane H M
Published: July 2020

Aims

Litterfall at a global scale is affected by climate, edaphic features and vegetation structure, with litter production increasing from grasslands to forests following the rise in standing biomass. However, at landscape scales, the same relationship between litter production and vegetation structure has rarely been studied and comparisons of litterfall patterns between adjacent, structurally distinct communities are lacking. Here, we use a standardized methodology to describe the structural differences among four savanna physiognomies and analyze their relationship with changes in litterfall across the Cerrado.

Methods

We evaluated the woody vegetation structure and composition in 48 sites, equally distributed across four physiognomies and monitored the monthly litter production from April 2014 to March 2015.

Important Findings

Results showed that the density, basal area, cylindrical volume and aboveground biomass of woody vegetation differ among physiognomies, increasing consistently from cerrado ralo, cerrado típico, cerrado denso and cerradão. Indeed, we found a strong and positive relationship between aboveground biomass and annual litter production, with litter yield increasing from 0.9 to 8.4 Mg ha−1 across different physiognomies, following the increment in vegetation structure. Monthly production was seasonal and similar among vegetation types, increasing during the dry season. Leaves comprised the dominant fraction (approx. 85%) and litterfall seasonality primarily resulted from the concentration of leaf shedding during dry months. However, the temporal pattern of litterfall throughout the year showed a gradual reduction in the seasonality from open to closed vegetation types, likely following the decrease of deciduous species abundance in the plant community. Our results showed that changes in vegetation structure may affect spatial and temporal litterfall patterns in different physiognomies, which co-occur across the Cerrado landscape, with potential implications for the overall functioning of this ecosystem. Moreover, these findings highlight the use of standardized methods as essential to correctly compare litterfall patterns among different environments.
On the properties of dissipative shocks in the relativistic accretion flows
Authors: Mondal Soumen , Basu Prasad
Published: July 2020

In this work, we study the properties of dissipative shocks for fully relativistic accretion flows around spinning black holes. In an accretion flow harbouring a dissipative shock (formally known as radiative shock), a significant portion of the thermal energy may get released from the post-shock corona. A stellar-mass black hole may therefore emit hard X-rays from the inner edge of the disc. If the bulk energy loss is significant, post-shock pressure drops, and shock moves forward towards the black hole compressing the size of the post-shock corona, resulting an enhancement of the corona temperature and compression ratio. The dynamical properties of the radiative shocks are therefore systematically investigated to understand accurately the radiative loss processes, temporal variations, and the spectral properties. We notice that the range of flow parameters (e.g. energy and angular momentum) responsible for the formation of ‘shocks in accretion (SA)’ is identical for both the cases of standing and dissipative shocks. The spin of the black hole enhances the dissipation further. We estimate the maximum energy release, which is observed close to $100{{\ \rm per\ cent}}$ in the extreme cases. This could be useful in explaining various observed phenomena namely the formation and the systematic evolution of quasi-periodic oscillations, and the time lags in between hard and soft X-ray photons (e.g. XTE J1550−564, GRO J1655−40, etc.) during their outbursts.
How to live with a meningioma: experiences, symptoms, and challenges reported by patients
Authors: Nassiri Farshad , Suppiah Suganth , Wang Justin Z , Badhiwala Jetan H , Juraschka Kyle , Meng Ying , Nejad Romina , Au Karolyn , Willmarth Nicole E , Cusimano Michael , Zadeh Gelareh
Published: July 2020

Background

We aimed to explore gaps in the care of meningioma patients that could improve quality of care by better understanding symptoms experienced by patients at various stages of treatment, and afterwards.

Methods

A novel 19-item self-administered questionnaire was provided for patients with meningiomas to complete by the American Brain Tumor Association (ABTA) over a 3-month period.

Results

A total of 1852 unique respondents were included. Nearly one-third of all respondents felt they received insufficient information about meningiomas at initial diagnosis (N = 607, 32.9%) and 28.8% (N = 530) believed they received insufficient information about treatment options. In fact, 34.5% of respondents received the majority of their information from the internet and nonhealthcare professionals. The most common concerns after initial diagnosis were risks associated with surgery and/or treatment (36.5%) followed by how the tumor would impact daily life (25%) and the risk of tumor recurrence (12.4%). Respondents indicated that a list of resources available for patients with meningiomas (N = 597, 32.3%) would have been most beneficial in regards to their disease experience after their initial diagnosis. Moreover, we found that a substantial proportion of patients continued to report symptoms long after treatment, with fatigue being the most common compared to before treatment (38.2% vs. 57.7%, χ2 = 128, P < .001).

Conclusions

Patients with meningiomas exhibit symptoms that continue well after treatment with fatigue and cognitive impairments as the most bothersome. Moreover, patients report key communication gaps that can be addressed to improve their disease experience and care.
A Business Archive of the French Illegal Slave Trade in the Nineteenth Century
Authors: la Hausse de Lalouvière Joseph
Published: July 2020

Following the abolition of the transatlantic trade in African captives, slave traders from France, Spain and Cuba devised strategies of concealment to perpetuate and even expand their enterprise. A close reading of the unexpurgated logbooks and business correspondence of the Jeune Louis, a French ship that transported more than three hundred captives from the Bight of Biafra to Havana in 1825, identifies three decisive innovations in the Franco-Cuban branch of the illegal slave trade. Transnational business structure, risk management through honour-based marine insurance policies, and redacted record keeping transformed the wider Atlantic slave-trading sector into one capable of eluding attempts at international suppression. The clandestine techniques that this transnational slaving network developed to skirt the law also distorted the archival record of that traffic. Accounting for the resulting distortions and disappearances will enable future researchers to better navigate them.
Dissecting MicroRNA–mRNA Regulatory Networks Underlying Sulfur Assimilation and Cadmium Accumulation in Poplar Leaves
Authors: Shi Wenguang , Liu Wenzhe , Ma Chaofeng , Zhang Yuhong , Ding Shen , Yu Wenjian , Deng Shurong , Zhou Jing , Li Hong , Luo Zhi-Bin
Published: July 2020

The process of cadmium (Cd) accumulation and detoxification under different sulfur levels remains largely unknown in woody plants. To investigate the physiological and transcriptomic regulation mechanisms of poplars in response to different sulfate (S) supply levels and Cd exposure, we exposed Populus deltoides saplings to one of the low, moderate and high S levels together with either 0 or 50 µM Cd. Cd accumulation was decreased in low S-treated poplar leaves, and it tended to be increased in high S-supplied leaves under the Cd exposure condition. Sulfur nutrition was deficient in low S-supplied poplars, and it was improved in high S-treated leaves. Cd exposure resulted in lower sulfur level in the leaves supplied with moderate S, it exacerbated a Cd-induced sulfur decrease in low S-treated leaves and it caused a higher sulfur concentration in high S-supplied leaves. In line with the physiological changes, a number of mRNAs and microRNAs (miRNAs) involved in Cd accumulation and sulfur assimilation were identified and the miRNA–mRNA networks were dissected. In the networks, miR395 and miR399 members were identified as hub miRNAs and their targets were ATP sulfurylase 3 (ATPS3) and phosphate 2 (PHO2), respectively. These results suggest that Cd accumulation and sulfur assimilation are constrained by low and enhanced by high S supply, and Cd toxicity is aggravated by low and relieved by high S in poplar leaves, and that miRNA–mRNA regulatory networks play pivotal roles in sulfur-mediated Cd accumulation and detoxification in Cd-exposed poplars.
Psychosocial and coping responses toward 2019 coronavirus diseases (COVID-19): a cross-sectional study within the Chinese general population
Authors: Li Q
Published: July 2020

Background

The 2019 coronavirus diseases (COVID-19) led out the mental health crisis.

Aim

To determine the psychological status and post-traumatic stress symptoms (PTSD) among general population (except confirmed and suspected cases, and close contacts) and their association with the coping strategy types during the COVID-19 outbreak.

Design

A cross-sectional study.

Methods

Participants were recruited from the community through snowball sampling with anonymous online questionnaires, using 28-item General Health Questionnaire, 22-item Impact of Events Scale-Revised and 28-item Brief Coping Inventory to measure their psychiatric disorders, PTSD level and coping strategies.

Results

Of the total 1109 participants, 42.65% and 67.09% self-reported psychiatric disorders and high PTSD level, respectively. Age, occupation and education level were significantly association with psychological status. The status of psychiatric disorders was also significantly related to high PTSD level. Using both emotion and problem coping was better for psychiatric status [adjusted odds ratio (aOR) = 0.72, 95% confidence interval (CI): 0.54–0.98], and problem-focused coping was significantly associated with high PTSD level (aOR = 2.09, 95% CI: 1.25–3.51).

Conclusion

Negative psychological outcomes were common among the general people during the COVID-19 outbreak, and the findings may provide references for intervention guidelines of mental health for the community population.
Psoriatic arthritis epidemiology, comorbid disease profiles and risk factors: results from a claims database analysis
Authors: Rech Jürgen , Sticherling Michael , Stoessel Daniel , Biermann Mona H C , Häberle Benjamin M , Reinhardt Maximilian
Published: July 2020

Objective

Psoriasis is a systemic inflammatory disease often accompanied by comorbidities, including metabolic syndrome, cardiovascular diseases and depression. Up to 41% of psoriasis patients develop psoriatic arthritis (PsA), making it one of the most relevant manifestations. A large health claims data set was analysed to determine the rate of PsA development in psoriasis patients. Furthermore, comorbid disease profiles of psoriasis patients with or without PsA were compared, and potential risk factors for the development of PsA were identified.

Methods

This was a non-interventional, retrospective analysis of anonymized insurance health claims data using a subset of the Institute of Applied Health Research Berlin (InGef) database. The primary outcome was the prevalence and incidence of diagnosed PsA among psoriasis patients in Germany. Risk factors for the development of PsA in psoriasis patients were determined by conditional logistic regression analysis.

Results

The cumulative percentage of patients with existing psoriasis developing concomitant PsA over 4 years was 3.44%, with a mean time to diagnosis of PsA of 1.5 years. Psoriasis patients diagnosed with acute rheumatism (odds ratio: 2.93, 95% CI = 1.76, 4.86; P < 0.001) or pain in unspecific joints (odds ratio: 1.74, 95% CI = 1.01, 2.99; P = 0.047) showed an increased risk for development of PsA later on. Interestingly, fewer than half of the patients with concomitant PsA consulted a rheumatologist.

Conclusions

Unspecific arthritic symptoms are likely to precede PsA diagnoses and can develop soon after onset of psoriasis, with accumulating risk over time. There is a high unmet need for early rheumatological assessment of psoriasis patients.
Contribution of Pulmonary CYP-mediated Bioactivation of Naphthalene to Airway Epithelial Injury in the Lung
Authors: Kovalchuk Nataliia , Zhang Qing-Yu , Van Winkle Laura , Ding Xinxin
Published: July 2020

Previous studies have established that cytochrome P450 enzymes (CYPs) in both liver and lung are capable of bioactivating naphthalene (NA), an omnipresent air pollutant and possible human carcinogen, in vitro and in vivo. The aim of this study was to examine the specific contribution of pulmonary CYPs in airway epithelial cells to NA-induced airway toxicity. We used a lung-Cpr-null mouse model, which undergoes doxycycline-induced, Cre-mediated deletion of the Cpr (a redox partner of all microsomal CYPs) gene specifically in airway epithelial cells. In 2-month-old lung-Cpr-null mice, Cpr deletion occurred in 75%–82% of epithelial cells of conducting airways. The extent of NA-induced acute lung toxicity (as indicated by total protein concentration and lactate dehydrogenase activity in bronchoalveolar lavage fluid collected at 24-h after initiation of a 4-h, nose-only, 10-ppm NA inhalation exposure) was substantially lower (by 37%–39%) in lung-Cpr-null mice, compared with control littermates. Moreover, the extent of cellular proliferation (as indicated by 5-bromo-2′-deoxyuridine incorporation) was noticeably lower in both proximal and distal airways (by 59% and 65%, respectively) of NA-treated lung-Cpr-null mice, compared with control littermates, at 2-day post-NA inhalation exposure. A similar genotype-related difference in the extent of postexposure cell proliferation was also observed in mice exposed to NA via intraperitoneal injection at 200 mg/kg. These results directly validate the hypothesis that microsomal CYP enzymes in airway epithelial cells play a large role in causing injury to airway epithelia following exposure to NA via either inhalation or intraperitoneal route.
Phylogenetic relationships and biogeographic range evolution in cat-eyed snakes,Boiga(Serpentes: Colubridae)
Authors: Weinell Jeffrey L , Barley Anthony J , Siler Cameron D , Orlov Nikolai L , Ananjeva Natalia B , Oaks Jamie R , Burbrink Frank T , Brown Rafe M
Published: July 2020

The genus Boiga includes 35, primarily arboreal snake species distributed from the Middle East to Australia and many islands in the western Pacific, with particularly high species diversity in South-East Asia. Despite including the iconic mangrove snakes (Boiga dendrophila complex) and the brown tree snake (Boiga irregularis; infamous for avian extinctions on small islands of the Pacific), species-level phylogenetic relationships and the biogeographic history of this ecologically and morphologically distinct clade are poorly understood. In this study, we sequenced mitochondrial and nuclear DNA for 24 Boiga species and used these data to estimate a robust phylogenetic inference, in order to (1) test the hypothesis that Boiga is monophyletic, (2) evaluate the validity of current species-level taxonomy and (3) examine whether geographic range evolution in Boiga is consistent with expectations concerning dispersal and colonization of vertebrates between continents and islands. Our results support the prevailing view that most dispersal events are downstream – from continents to oceanic islands – but we also identify a role for upstream dispersal from oceanic islands to continents. Additionally, the novel phylogeny of Boiga presented here is informative for updating species-level taxonomy within the genus.
The AAMC Standardized Video Interview: Lessons Learned From the Residency Selection Process
Authors: Gallahue Fiona E. , Deiorio Nicole M. , Blomkalns Andra , Bird Steven B. , Dunleavy Dana , Fraser Rebecca , Overton B. Renee
Published: July 2020

Calls to change the residency selection process have increased in recent years, with many focusing on the need for holistic review and alternatives to academic metrics. One aspect of applicant performance to consider in holistic review is proficiency in behavioral competencies. The Association of American Medical Colleges (AAMC) developed the AAMC Standardized Video Interview (SVI), an online, asynchronous video interview that assesses applicants’ knowledge of professionalism and their interpersonal and communication skills. The AAMC worked with the emergency medicine community to pilot the SVI. Data from 4 years of research (Electronic Residency Application Service [ERAS] 2017–2020 cycles) show the SVI is a reliable, valid assessment of these behavioral competencies. It provides information not available in the ERAS application packet, and it does not disadvantage individuals or groups. Yet despite the SVI’s psychometric properties, the AAMC elected not to renew or expand the pilot in residency selection.

In this Invited Commentary, the authors share lessons learned from the AAMC SVI project about introducing a new tool for use in residency selection. They recommend that future projects endeavoring to find ways to support holistic review engage all stakeholders from the start; communicate the value of the new tool early and often; make direct comparisons with existing tools; give new tools time and space to succeed; strike a balance between early adopters and broad participation; help stakeholders understand the limitations of what a tool can do; and set clear expectations about both stakeholder input and pricing. They encourage the medical education community to learn from the SVI project and to consider future partnerships with the AAMC or other specialty organizations to develop new tools and approaches that prioritize the community’s needs. Finding solutions to the challenges facing residency selection should be a priority for all stakeholders.
Leading by Design: Lessons for the Future From 25 Years of the Executive Leadership in Academic Medicine (ELAM) Program for Women
Authors: Jagsi Reshma , Spector Nancy D.
Published: July 2020

The Hedwig van Ameringen Executive Leadership in Academic Medicine (ELAM) Program for Women is designed to promote the careers of senior female leaders in academic health care in a way that ultimately seeks to transform culture and promote gender equity far beyond the careers of its participants. In an era of increased awareness of gender inequity within academic medicine, the longevity of the ELAM program raises several important questions. First, why is such a program still needed? Second, what exactly does it do, and what has been its influence on its participants and beyond? And third, what lessons can ELAM’s example provide to help guide the medical profession as it strives to promote gender equity in the field? In this Invited Commentary, the authors seek to answer these questions from the perspective of a recent program participant and the current program director. The authors review the evidence that identifies how women, even today, face accumulating disadvantage over the course of their academic careers, stemming from repeated encounters with powerful unconscious biases and stereotypes, societal expectations for a gendered division of domestic labor, and still-present overt discrimination and sexual harassment. They describe ELAM’s approach, which builds the knowledge and skills of the women who participate in the program, while also intentionally raising their visibility within their home institutions so that they have opportunities to share with institutional leaders what they have learned in ways that not only promote their own careers but also support gender equity in the broader environment. The authors conclude by offering thoughts on how ELAM’s model may be leveraged in the future, ideally in partnership with the numerous professional societies, funding agencies, and other organizations that are committed to accelerating the rate of progress toward gender equity at all levels of academic medicine.