bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk Factor Analysis of Children's Exposure to Microbial Pathogens in Playgrounds
Authors: Chatziprodromidou Ioanna P. , Chatziantoniou Stella , Vantarakis George , Vantarakis Apostolos
Published: May 2021

Bacteria are commonly found in soil and may cause health risks to children playing in the outdoor playgrounds with soil, mainly via hand to mouth and pica behaviors. Our study concerned with the risk analysis of infection of a child playing in urban playgrounds in the cities of Patras and Pyrgos in Greece. The presence of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa were analyzed in soil samples of these playgrounds. A standardized questionnaire depicted the individual characteristics of each playground and recorded risk factors in playgrounds related to bacterial infections. Furthermore, the distributions of E. coli, S. aureus and P. aeruginosa were analyzed in soil samples. Our results were investigated with beta‐Poisson models using the Quantitative Microbial Risk Assessment wiki models to evaluate and construct a probability model of infection for each of these bacteria. The risk of infection was higher during the wet period. The risk was higher for P. aeruginosa infection compared to E. coli and S. aureus ones. Nevertheless, the bacterial concentration was higher for E. coli than P. aeruginosa and S. aureus in both wet and dry periods. Our results provide new data that could contribute in assessing the risks associated with playgrounds where children can unaware play in urban parks.
Extracorporeal CO2 removal and renal replacement therapy in acute severe respiratory failure in COVID‐19 pneumonia: Case report
Authors: Gacitúa Ignacio , Frías Alondra , Sanhueza María E. , Bustamante Sergio , Cornejo Rodrigo , Salas Andrea , Guajardo Ximena , Torres Katherine , Figueroa Canales Enzo , Tobar Eduardo , Navarro Rocío , Romero Carlos
Published: May 2021

The COVID‐19 pandemic significates an enormous number of patients with pneumonia that get complicated with severe acute respiratory distress syndrome (ARDS), some of them with refractory hypercapnia and hypoxemia that need mechanical ventilation (MV). Those patients who are not candidate to extracorporeal membrane oxygenation (ECMO), the extracorporeal removal of CO2 (ECCO2R) can allow ultra protective MV to limit the transpulmonary pressures and avoid ventilatory induced lung injury (VILI).

We report a first case of prolonged ECCO2R support in 38 year male with severe COVID‐19 pneumonia refractory to conventional support. He was admitted tachypneic and oxygen saturation 71% without supplementary oxygen. The patient's clinical condition worsens with severe respiratory failure, increasing the oxygen requirement and initiating MV in the prone position. After 21 days of protective MV, PaCO2 rise to 96.8 mmHg, making it necessary to connect to an ECCO2R system coupled continuous veno‐venous hemodialysis (CVVHD). However, due to the lack of availability of equipment in the context of the pandemic, a pediatric gas exchange membrane adapted to CVVHD allowed to maintain the removal of CO2 until completing 27 days, being finally disconnected from the system without complications and with a satisfactory evolution.
Head pre‐cooling improves 5‐km time‐trial performance in male amateur runners in the heat
Authors: Coelho Leonardo G. M. , Ferreira‐Júnior João B. , Williams Thomas B. , Maia‐Lima André , Borba Diego A. , Silva Cristiano D. , Coelho Daniel B. , Barros Cristiano L. M. , Prado Luciano S. , Silami‐Garcia Emerson
Published: May 2021

This study aimed to evaluate the effect of head pre‐cooling on the 5‐km time‐trial performance of amateur runners in the heat. In a counterbalanced design, 15 male amateur runners (22.6 ± 3.5 y; VO2 max in heat 42.3 ± 4.4 mLO2/kg/min) completed two 5‐km time trials performed in the heat (35°C, 50% relative humidity). In one trial (HCOOL), participants underwent 20 min of head cooling in a temperate environment (23°C, 70% relative humidity) prior to exercise. In another trial (CON), exercise was preceded by 20 min of rest under the same temperature conditions. Exercise time was shorter in HCOOL (25 min and 36 s ± 3 min) compared to CON (27 ± 3 min; p = 0.02). Rectal temperature was reduced during the pre‐exercise intervention in HCOOL (p < 0.001), but not in CON (p = 0.55). Relative changes in rectal temperature and mean head temperature were lower throughout HCOOL when compared with CON condition (p = 0.005 and p = 0.022, respectively). Mean skin temperature, heart rate, and rating of perceived exertion did not differ between HCOOL and CON conditions throughout exercise (p = 0.20, p = 0.52 and 0.31, respectively). Thermal comfort was lower in HCOOL condition in pre‐exercise (p = 0.014) with no differences observed throughout exercise (p = 0.61). 5‐km running performance in a hot environment was improved after a 20‐min head cooling intervention, suggesting that this method may be practical as pre‐cooling strategy and easily administered to both professional and amateur runners alike.
Civic and Political Engagement during the Multifaceted COVID‐19 Crisis
Authors: Borbáth Endre , Hunger Sophia , Hutter Swen , Oana Ioana‐Elena
Published: May 2021

Measures to cope with the COVID‐19 pandemic have put a sudden halt to street protests and other forms of citizen involvement in Europe. At the same time, the pandemic has increased the need for solidarity, motivating citizens to become involved on behalf of people at risk and the vulnerable more generally. This research note empirically examines the tension between the demobilisation and activation potential of the COVID‐19 crisis. Drawing on original survey data from seven Western European countries, we examine the extent, forms, and drivers of citizens’ engagement. Our findings show the remarkable persistence of pre‐existing political and civic engagement patterns. Concurrently, we show that threat perceptions triggered by the multifaceted COVID‐19 crisis have mobilized Europeans in the early phase of the pandemic. Similarly, the role of extreme ideological orientations in explaining (regular) political engagement indicates that the current situation may create its specific mobilisation potentials.
Repeat proliferation and partial endoreplication jointly shape the patterns of genome size evolution in orchids
Authors: Chumová Zuzana , Záveská Eliška , Hloušková Petra , Ponert Jan , Schmidt Philipp‐André , Čertner Martin , Mandáková Terezie , Trávníček Pavel
Published: May 2021

Although the evolutionary drivers of genome size change are known, the general patterns and mechanisms of plant genome size evolution are yet to be established. Here we aim to assess the relative importance of proliferation of repetitive DNA, chromosomal variation (including polyploidy), and the type of endoreplication for genome size evolution of the Pleurothallidinae, the most species‐rich orchid lineage. Phylogenetic relationships between 341 Pleurothallidinae representatives were refined using a target enrichment hybrid capture combined with high‐throughput sequencing approach. Genome size and the type of endoreplication were assessed using flow cytometry supplemented with karyological analysis and low‐coverage Illumina sequencing for repeatome analysis on a subset of samples. Data were analyzed using phylogeny‐based models. Genome size diversity (0.2–5.1 Gbp) was mostly independent of profound chromosome count variation (2n = 12–90) but tightly linked with the overall content of repetitive DNA elements. Species with partial endoreplication (PE) had significantly greater genome sizes, and genomic repeat content was tightly correlated with the size of the non‐endoreplicated part of the genome. In PE species, repetitive DNA is preferentially accumulated in the non‐endoreplicated parts of their genomes. Our results demonstrate that proliferation of repetitive DNA elements and PE together shape the patterns of genome size diversity in orchids.
GmPTF1 modifies root architecture responses to phosphate starvation primarily through regulating GmEXPB2 expression in soybean
Authors: Yang Zhaojun , Gao Zhi , Zhou Huiwen , He Ying , Liu Yanxing , Lai Yelin , Zheng Jiakun , Li Xinxin , Liao Hong
Published: May 2021

Though root architecture modifications may be critically important for improving phosphorus (P) efficiency in crops, the regulatory mechanisms triggering these changes remain unclear. In this study, we demonstrate that genotypic variation in GmEXPB2 expression is strongly correlated with root elongation and P acquisition efficiency, and enhancing its transcription significantly improves soybean yield in the field. Promoter deletion analysis was performed using 5′ truncation fragments (P1–P6) of GmEXPB2 fused with the GUS gene in soybean transgenic hairy roots, which revealed that the P1 segment containing three E‐box elements significantly enhances induction of gene expression in response to phosphate (Pi) starvation. Further experimentation demonstrated that GmPTF1, a basic‐helix‐loop‐helix transcription factor, is the regulatory factor responsible for the induction of GmEXPB2 expression in response to Pi starvation. In short, Pi starvation induced expression of GmPTF1, with the GmPTF1 product directly binding to the E‐box motif in the P1 region of the GmEXPB2 promoter. Plus, both GmPTF1 and GmEXPB2 highly expressed in lateral roots, and were significantly enhanced by P deficiency. Further work with soybean stable transgenic plants through RNA sequencing analysis showed that altering GmPTF1 expression significantly impacted the transcription of a series of cell wall genes, including GmEXPB2, and thereby affected root growth, biomass and P uptake. Taken together, this work identifies a novel regulatory factor, GmPTF1, involved in changing soybean root architecture partially through regulation of the expression of GmEXPB2 by binding the E‐box motif in its promoter region.
Surgical treatment and outcome of sterile prostatic cysts in dogs
Authors: Del Magno Sara , Pisani Guido , Dondi Francesco , Cinti Filippo , Morello Emanuela , Martano Marina , Foglia Armando , Giacobino Davide , Buracco Paolo
Published: May 2021

Objective

To describe the surgical treatment and outcome of a large cohort of dogs with sterile prostatic cysts (PCs).

Study Design

Retrospective study.

Animals

Forty‐four client‐owned dogs.

Methods

Dogs with sterile PCs with at least 6 months of follow‐up were included. Clinical variables, type of surgery, complications, recurrences, and outcomes (telephonic interviews or rechecks) were recorded.

Results

Extra‐ and intraparenchymal cysts were diagnosed in 29 and 11 dogs, respectively. Four dogs had both types. Extraparenchymal cysts were treated by partial resection and omentalization (n = 22) and complete resection (n = 7). Drainage and intracapsular omentalization were performed in all dogs with intraparenchymal cysts. The four dogs with both types of cyst were treated by omentalization. Resolution was documented in 39/44 dogs (88.6%). Intraoperative complications occurred in one dog (urethral tear). Major complications resulting in death occurred in three dogs (oliguric kidney injury, cardiac arrhythmia, and persisting urinary tract obstruction). Minor complications (n = 10) consisted of temporary urinary incontinence (n = 2), permanent urinary incontinence (n = 5), urinary retention (n = 2), and dysuria (n = 1). Recurrence occurred in two dogs with extraparenchymal cysts. Median long‐term follow‐up was 528 days (range, 250–730 days). Thirty‐nine dogs had no signs associated with prostatic disease at long‐term follow‐up.

Conclusion

Partial or complete resection and/or omentalization of sterile PCs led to resolution of clinical signs in most dogs, although postoperative urinary incontinence was frequent.

Impact

This study is the largest case series relative to canine sterile PCs treated surgically and provides evidence on the prognosis and rate of complications.
Effect of irrigation technique on the vertebral canal temperature during thoracolumbar hemilaminectomy in dogs: An ex vivo study
Authors: Dongaonkar Kaustubh R. , Aoki Koji , Zwueste Danielle , Bates Miriam
Published: May 2021

Objective

To determine the influence of continuous and intermittent bolus irrigation on vertebral canal temperature during thoracolumbar hemilaminectomy.

Study Design

Ex vivo study.

Sample Population

Ten canine cadavers.

Methods

Six consecutive thoracolumbar hemilaminectomies starting at T12‐13 with alternating left‐ or right‐side selection, and alternating continuous or intermittent bolus irrigation were performed in each dog resulting in 30 hemilaminectomies per irrigation technique. Drilling was performed for 15 s followed by a 10‐s pause and resumed until completion of hemilaminectomy. Continuous irrigation consisted of saline delivered at 15 ml/min during drilling. Bolus irrigation consisted of manual delivery of 10 ml saline during the pause. Temperatures were recorded with two sensors placed within the vertebral canal adjacent to target hemilaminectomy site and compared between techniques with a linear mixed model.

Results

Intermittent bolus irrigation was associated with lower peak vertebral canal temperatures (mean 15.7°C; range 9.4–23.3°C) than continuous irrigation (mean 16.7°C; range 9.6–27.6°C, p = .003) (mean difference of 1.1°C, p = .006). Similarly, mean vertebral canal temperatures remained lower when hemilaminectomies were performed under intermittent rather than continuous irrigation (mean difference of 0.48°C, p = .006, linear mixed model).

Conclusion

Lower vertebral canal temperatures were maintained during hemilaminectomy with intermittent bolus rather than continuous irrigation.

Clinical Significance

Both intermittent bolus and continuous irrigation are suitable to prevent elevations in canine vertebral canal temperature during hemilaminectomy.
Influence of interlocking thread screws to repair simulated adult canine humeral condylar fractures
Authors: Raleigh Joseph S. , Filliquist Barbro , Kapatkin Amy S. , Chou Po Yen , Marcellin‐Little Denis J. , Garcia Tanya C. , Jacques Kevin L. , Stover Susan M.
Published: May 2021

Objective

To determine the influence of interlocking screw threads on the biomechanical properties of repaired canine humeral condylar fractures.

Study Design

Ex vivo biomechanical study.

Sample Population

Thirty‐six humeral condyles.

Methods

Simulated fractures of the lateral aspect of the humeral condyle were stabilized by a 3.5 mm interlocking thread screw (ITS) or 3.5 mm buttress thread screw placed in lag (BTS‐L) or positional fashion (BTS‐P) and axially loaded at a walk, trot, 2‐mm displacement, and failure cycles. Compact flute drill bits (CFBs) were used for ITS constructs and standard flute drill bits (SFB) for BTS constructs. The effects of bit type on drilling parameters and screw type on screw insertion properties and fragment stability were assessed.

Results

CFB produced a 6°C greater temperature increase (p = .042) and required 20 N higher torque (p = .003) than SFB. Insertional torque was greater for ITS than BTS‐P (p = .001) and BTS‐L (p = .001). Condylar fragment rotation at failure was lower in ITS (lsmean ± SE, 8.3° ± 1.9°) than BTS‐L constructs (14.5° ± 2.3°,p = .011). ITS resisted greater loads (1503 ± 105 N) than BTS‐P (1189 ± 99 N,p = .038) but not BTS‐L (1249 ± 123 N,p = .121) constructs.

Conclusion

Biomechanical performance of constructs was improved with ITS rather than BTS fixation.

Clinical Significance

ITS can be considered for stabilization of humeral condylar fractures in adult dogs.
‘It's our job’: Constraints to investigation of atypical disease events—Opinions of Australian veterinarians
Authors: Steele Sandra G. , Mor Siobhan M. , Toribio Jenny‐Ann L.M.L.
Published: May 2021

Frontline health practitioners need to be adequately prepared to recognize and respond to atypical disease presentations, some of which may have zoonotic potential. Data from previous research have suggested that veterinarians may face challenges in investigation of disease events due to time and money constraints. As part of an Australia‐wide survey project, veterinarians were asked to answer an open‐ended question regarding potential constraints in investigation of atypical disease events where there may be concern about a zoonosis or emerging infectious disease. Qualitative data were analysed using thematic content analysis with the consideration of the respondent's area of practice and level of experience. Five main themes were identified which encapsulated constraints to disease investigation described by participants, namely: (a) financing of disease investigations, including client willingness/ability to pay in absence of alternative government schemes; (b) client‐related factors, including willingness to consent to investigation and comply with instructions; (c) professional preparedness to act, related to practitioner knowledge and technical competency; (d) workplace environment, impacted by physical, logistical and managerial aspects of workplaces; and (e) access to external technical support, primarily from government veterinary services. Successful investigation and management of atypical diseases, including potential zoonoses, requires preparedness of all veterinarians. Continuing professional education for veterinarians in infection prevention and control and biosecurity, alongside adequate government funding and support will help facilitate optimal health and biosecurity outcomes. Both state and federal governments need to review existing animal health structures to ensure cohesive responses for future disease events.
Increasing Mobile Robot Efficiency and Versatility Through Manipulation-Driven Adaptation1
Authors: Kim Raymond , Madabushi Varun , Dong Eric , Mazumdar Anirban
Published: May 2021

Terrestrial mobile robotics are crucial to a range of missions including planetary exploration, search and rescue, logistics, and national security. Many of these missions require the robot to operate on a broad variety of terrain. Wheels are ideal for energy efficiency but can suffer catastrophic failure when presented with obstacles or complex ground. Legs can help traverse obstacles but at the cost of energy efficiency. Physical adaptation can enable a robot to benefit from both modes of locomotion. This article describes a new approach to physical adaptation through manipulation. Specifically, this article examines how manipulators can be used to change the vehicle’s mode of locomotion and improve energy efficiency and versatility. This article presents “swappable propulsors,” which can be easily attached/detached to adapt the vehicle through the use of permanent magnets. A new robot system that uses its manipulator to discretely switch between wheeled and legged locomotion is created. The experimental results demonstrate how this approach provides a unique combination of energy efficiency and versatility. This study describes the design of swappable propulsors, analyzes how to manipulate them, and describes how they can be used to improve performance. This study extends on prior work with additional analysis, an improved robot prototype, and new experimental results.
Accurate Boundary Layer Measurements Using Hot-Wire Anemometry—Improvements and Error Analysis
Authors: Chemnitz Silvio , Niehuis Reinhard
Published: May 2021

In this article, two approaches are presented dealing with common challenges of two-dimensional boundary layer measurements with hot wire anemometry under challenging test conditions. Novel procedures for accurate determination of the sensor position and correction of the wall heat effect were developed and tested at high freestream velocities of about M1 = 0.3 and thin boundary layers (δ99 = 0.7 − 3.5 mm) of different transitional state in a low-density environment. First, a novel procedure for automatized determination of the accurate hot wire sensor position relative to the wall is presented. The quantification and correction of possible subminiature sensor misalignments is achieved by taking advantage of the linear nature of the laminar sublayer of each boundary layer. The statistical approaches for identification and verification of the linear sublayer demonstrate satisfying results of minimized position uncertainties of about 24 μm. Second, a highly adaptable method for correction of the well-known wall heat effect is presented. In contrary to a series of static correction approaches, the biased velocity information is corrected by optimizing the parameters of an exponential approach, where the correction term is optimized for each boundary layer individually. This novel approach resolves the problem of the limited applicability of static correction methods, caused by system inherent measurement uncertainties.
Multi-Objective Optimization of Structural Parameters of Air-Cooled System for Lithium Battery Pack Based on Surrogate Model
Authors: Bao Nengsheng , Wei Li , Ma Chong , Fan Yuchen , Li Tuyan
Published: May 2021

The new energy electric vehicle, which takes clean electric energy as the main driving force, has no pollutants and exhaust emissions during its operation and has a higher energy utilization ratio than the fuel locomotive. Therefore, electric vehicles have been widely developed in recent years. The maximum temperature and temperature consistency of the battery pack in the electric vehicle have a great influence on the life and safety of the battery. In this paper, the thermal management system of the lithium battery pack was taken as the research object. The temperature distribution and uniformity of the battery pack under different heat dissipation conditions were analyzed based on computational fluid dynamics (CFD). The multi-objective optimization method of the battery pack thermal management system was carried out by combining the surrogate model with fast non-dominated sorting genetic algorithm (NSGA-II). The maximum temperature of the battery pack obtained from candidate point 1 is 310.72 K, which is 4.99 K lower than the initial model temperature, and the temperature standard deviation is 0.76 K, with a reduction rate of 51.9%. Experiment results showed that maximum difference between the optimized and experimental value of the maximum temperature is 0.8 K, and the error was within 1 K. Therefore, the multi-objective optimization method proposed in this paper has high accuracy.
An Accelerating Sweep Frequency Excitation Method for the Rotordynamic Coefficients Identification of Annular Gas Seals Based on Computational Fluid Dynamics
Authors: Gu Qianlei , Yang Jiangang , Zhang Wanfu , Zhang Mingjie
Published: May 2021

This article proposes a rotordynamic identification method using the accelerating sweep frequency excitation method. The computational fluid dynamics transient solution combined with the moving grid method is utilized to obtain the transient flow field of the seal excited by the whirling rotor with an accelerating frequency. Rotordynamic coefficients at swept frequencies are obtained by analyzing the transient response force acting on the rotor. Rotordynamic coefficients of three published experimental seals including a labyrinth seal, a fully partitioned pocket damper seal and a honeycomb seal are identified to validate the proposed method. The results show that the predicted rotordynamic coefficients are all well agreement with the trend of experimental data. Compared with the existing numerical models based on transient solutions, the central processing unit consumption of the proposed method is substantially reduced by 98% when achieving the same frequency resolution. In addition, the impact of the exciting acceleration on the identification accuracy is also illustrated.
Water Hammer and Harmonic Excitation Response With Fluid-Structure Interaction in Elbow Piping
Authors: Oinonen Ahti
Published: May 2021

This study focuses on the numerical analysis of a piping structure subjected to the water-hammer event caused by a rapid valve closure that is combined with external harmonic loading representing an idealized machine excitation. The fluid–structure interaction procedure applied to solutions involves the method of characteristic for the fluid equations with the finite element method for pipe structures, which are modeled as beams. Junction coupling at the pipe elbow governs the two-way coupled fluid–structure interaction, and both the friction and Poisson couplings are incorporated as well. There is an application on a piping structure that consists of a valve, tank, and elbow that are defined as boundary conditions. The solved result quantities include pressure and bending stress responses as well as dynamic displacement modes of the piping structure. Comparisons of the results show that water hammer loading combined with the mechanical excitation load induces significantly increased displacements and higher stress peaks when frequencies of the harmonic load and the acoustic natural mode of the piping system coincide. Additionally, the resulting mode of lateral structural vibration of the piping member closely resembles an analytically solved eigenmode of the beam. The conclusion is that dynamically changing flows due to a water hammer event can solely excite natural frequencies of the piping structure causing resonance in the system.
On the compromise between noise reduction and speech/noise spatial information preservation in binaural speech enhancement
Authors: Leng Xin , Chen Jingdong , Benesty Jacob
Published: May 2021

Spatial information is important for human perception of speech and sound signals. However, this information is often either distorted or completely neglected in noise reduction because it is challenging, to say the least, to achieve optimal noise reduction and accurate spatial information preservation at the same time. This paper studies the problem of binaural speech enhancement. By jointly diagonalizing the speech and noise correlation matrices, we present a method to construct the noise reduction filter as a linear combination of different eigenvectors, which span a certain subspace of the entire space. A different dimension of the subspace gives a different trade-off between noise reduction and speech/noise spatial information preservation. On the one side, if the dimension is equal to 1, maximum noise reduction is achieved but at the price of significant spatial information distortion. On the other extreme, if the dimension of the subspace is equal to that of the entire space, spatial information is accurately preserved but at the cost of no noise reduction. Therefore, one can achieve different levels of compromises between the amount of noise reduction and the level of speech/noise spatial information preservation by adjusting the dimension of the used subspace.
Performance of Three SARS-CoV-2 Immunoassays, Three Rapid Lateral Flow Tests, and a Novel Bead-Based Affinity Surrogate Test for the Detection of SARS-CoV-2 Antibodies in Human Serum
Authors: Krone Manuel , Gütling Julia , Wagener Johannes , Lâm Thiên-Trí , Schoen Christoph , Vogel Ulrich , Stich August , Wedekink Florian , Wischhusen Jörg , Kerkau Thomas , Beyersdorf Niklas , Klingler Silvana , Backes Simone , Dölken Lars , Gasteiger Georg , Kurzai Oliver , Schubert-Unkmeir Alexandra
Published: May 2021

For the control of immunity in COVID-19 survivors and vaccinated subjects, there is an urgent need for reliable and rapid serological assays. Based on samples from 63 COVID-19 survivors up to 7 months after symptom onset, and on 50 serum samples taken before the beginning of the pandemic, we compared the performances of three commercial immunoassays for the detection of SARS-CoV-2 IgA and IgG antibodies (Euroimmun SARS-COV-2 IgA/IgG, Mikrogen
recom
Well SARS-CoV-2 IgA/IgG, and Serion ELISA
agile
SARS-CoV-2 IgA/IgG) and three rapid lateral flow (immunochromatographic) tests (Abbott PanBio COVID-19 IgG/IgM, Nadal COVID-19 IgG/IgM, and Cleartest Corona 2019-nCOV IgG/IgM) with a 50% plaque-reduction neutralization test (PRNT50) representing the gold standard.
Evolution of Interbacterial Antagonism in Bee Gut Microbiota Reflects Host and Symbiont Diversification
Authors: Steele Margaret I. , Moran Nancy A.
Published: May 2021

Antagonistic interactions between bacteria affect diversity and dynamics of host-associated communities, including gut communities that are linked to host health. In many bacterial communities, including human and honey bee gut microbiotas, antagonism is mediated by type VI secretion systems (T6SSs) that deliver lethal toxins to competing strains.
New insights into the formation and emplacement of impact melt rocks within the Chicxulub impact structure, following the 2016 IODP-ICDP Expedition 364
Authors: de Graaff Sietze J. , Kaskes Pim , Déhais Thomas , Goderis Steven , Debaille Vinciane , Ross Catherine H. , Gulick Sean P.S. , Feignon Jean-Guillaume , Ferrière Ludovic , Koeberl Christian , Smit Jan , Mattielli Nadine , Claeys Philippe
Published: May 2021

This study presents petrographic and geochemical characterization of 46 pre-impact rocks and 32 impactites containing and/or representing impact melt rock from the peak ring of the Chicxulub impact structure (Yucatán, Mexico). The aims were both to investigate the components that potentially contributed to the impact melt (i.e., the pre-impact lithologies) and to better elucidate impact melt rock emplacement at Chicxulub. The impactites presented here are subdivided into two sample groups: the lower impact melt rock–bearing unit, which intrudes the peak ring at different intervals, and the upper impact melt rock unit, which overlies the peak ring. The geochemical characterization of five identified pre-impact lithologies (i.e., granitoid, dolerite, dacite, felsite, and limestone) was able to constrain the bulk geochemical composition of both impactite units. These pre-impact lithologies thus likely represent the main constituent lithologies that were involved in the formation of impact melt rock. In general, the composition of both impactite units can be explained by mixing of the primarily felsic and mafic lithologies, but with varying degrees of carbonate dilution. It is assumed that the two units were initially part of the same impact-produced melt, but discrete processes separated them during crater formation. The lower impact melt rock–bearing unit is interpreted to represent impact melt rock injected into the crystalline basement during the compression/excavation stage of cratering. These impact melt rock layers acted as delamination surfaces within the crystalline basement, accommodating its displacement during peak ring formation. This movement strongly comminuted the impact melt rock layers present in the peak ring structure. The composition of the upper impact melt rock unit was contingent on the entrainment of carbonate components and is interpreted to have stayed at the surface during crater development. Its formation was not finalized until the modification stage, when carbonate material would have reentered the crater.
Combination of ectopic pancreas and intestinal malrotation presenting as non-specific right iliac fossa pain in a SARS-CoV-2 positive patient
Authors: Hwang Woochan , Nemeth Kristof , White Annabelle , Bonomo Luca
Published: May 2021

We describe the case of a 31-year-old man who presented with a 3-day history of right iliac fossa pain with associated nausea and vomiting. He denied any previous incidents of abdominal pain and had no relevant medical history or family history to note. Given the typical history, examination findings of localised peritonism and infection risk, he was taken to theatre for laparoscopic appendicectomy without diagnostic imaging. Intraoperatively, we noted gut malrotation and an inflammatory jejunal mass which was resected after converting to a mini-laparotomy. The inflammatory mass was reported to be an ectopic pancreatic tissue from histology. Given that this patient had tested positive for SARS-CoV-2 on admission, we propose a possible case of SARS-CoV-2 infection triggering inflammation of the ectopic pancreatic tissue.
Retrospective review of work-related injuries sustained by foreign workers: a single centre experience over 10 years
Authors: Quek Yong Jing Daniel , Vijayasrinivasan Shilpa , Narayanan Aishwarya , Tham Kum Ying
Published: May 2021

Objectives

To investigate current patterns of work-related injuries sustained by foreign workers in Singapore and compare them to a decade ago. Secondary aim to analyse usefulness of selected trauma scores in this context.

Design

Retrospective review of trauma registry of a single centre, from 1 April to 30 June 2015. Data compared with those from similar study performed at same centre in 2004.

Setting

Emergency department (ED) of 1500-bedded acute urban public hospital in Singapore.

Participants

1094 foreign workers with work-related injuries were included. Tourists, foreign students, non-work-related injuries, re-attendances for the same condition were excluded.

Results

Mean age of participants was 32.8 years (SD 7.8), 90.0% were men. ED attendance was lowest on Sundays. Mechanism of injury: blunt (78.2%), penetrating (19.2%), burns (2.6%). Compared to 2004, 5% of foreign workers required admission (vs 19.6% in 2004, p≤0.0001), 8.0% underwent day or inpatient surgical procedures (vs 13.2% in 2004, p≤0.0001), 41.6% were referred to specialist outpatient clinics (vs 27.6% in 2004, p≤0.0001), 12.5% were referred to primary care follow-up (vs 29.9% in 2004, p≤0.0001). Mean duration of sick days was 4.3 (vs 5.1 in 2004, p≤0.0001). Of admitted patients, 49.1% had extremity injuries and 36.3% had head and neck injuries. Mean Injury Severity Score (ISS) for admitted patients was 3.64 (SD 3.1) (vs 4.3 (SD 5.5) in 2004, p=0.39). Mean Revised Trauma Score (RTS) for admitted patients was 7.74 (SD 0.39) (vs 7.8 (SD 0.2) in 2004, p=0.07). Of discharged patients, 48.9% had extremity injuries and 48.9% had external injuries. There was no death.

Conclusion

Compared to 2004, there were fewer major/fatal work-related injuries and an increased proportion of minor injuries. ISS and RTSs were of limited use in this setting.
Minimum acceptable diet and associated factors among infants and young children aged 6–23 months in Amhara region, Central Ethiopia: community-based cross-sectional study
Authors: Molla Abebaw , Egata Gudina , Getacher Lemma , Kebede Bezie , Sayih Alemayehu , Arega Mikyas , Bante Agegnehu
Published: May 2021

Objective

The main objective of this study was to assess the prevalence of a minimum acceptable diet (MAD) and associated factors.

Design

Community-based cross-sectional study

Setting

Debre Berhan Town, Ethiopia.

Participants

An aggregate of 531 infants and young children mother/caregiver pairs participated in this study. A one-stage cluster sampling method was used to select study participants and clusters were selected using a lottery method. Descriptive statistics were calculated for all study variables. Statistical analysis was performed on data to determine which variables are associated with MAD and the results of the adjusted OR with 95% CI. P value of <0.05 considered statistically significant.

Primary outcome

Prevalence of MAD and associated factors

Results

The overall prevalence of MAD was 31.6% (95% CI: 27.7 to 35.2). Having mother attending secondary (adjusted OR, AOR=4.9, 95% CI: 1.3 to 18.9) and college education (AOR=6.4, 95% CI: 1.5 to 26.6), paternal primary education (AOR=1.3, 95% CI: 1.5 to 2.4), grouped in the aged group of 12–17 months (AOR=1.8, 95% CI: (1.0 to 3.4) and 18–23 months (AOR=2.2, 95% CI: 1.2 to 3.9), having four antenatal care (ANC) visits (AOR=2.0, 95% CI: 1.0 to 3.9), utilising growth monitoring (AOR=1.8, 95% CI: 1.1 to 2.9), no history of illness 2 weeks before the survey (AOR=2.9, 95% CI: 1.5 to 6.0) and living in the household with home garden (AOR=2.5, 95% CI: 1.5 to 4.3) were positively associated with increase the odds of MAD.

Conclusion

Generally, the result of this study showed that the prevalence of minimum acceptable was very low. Parent educational status, ANC visits, infant and young child feeding advice, child growth monitoring practice, age of a child, a child has no history of illness 2 weeks before the survey, and home gardening practice were the predictors of MAD. Therefore, comprehensive intervention strategies suitable to the local context are required to improve the provision of MAD.
Lessons from the frontlines: a junior doctor’s experience of the first wave of the COVID-19 pandemic in a resource-limited setting
Authors: Subhani Brabaharan , Wijayaratne Dilushi , Jayasinghe Saroj
Published: May 2021

COVID-19 has stressed healthcare systems across the globe. We present the experience of an intern medical officer working in a tertiary care hospital during the first wave of the pandemic in Sri Lanka. Her narrative describes how the stress of the pandemic brought into sharp focus the strengths and weaknesses in the health system. We suggest some strategies to improve our health services as the world faces the second wave and an uncertain future. These include structural changes in healthcare services at institutional and national levels, focused educational programmes for healthcare professionals to impart generic skills of disaster management, and the development of telehealth services and computerisation of health systems. We believe that we must maintain this focus to ensure that our patients can be guaranteed quality healthcare in the future.
Landau levels for graphene layers in noncommutative plane
Authors: Sourrouille Lucas
Published: May 2021

Starting from the zero modes of the single and bilayer graphene Hamiltonians we develop a mechanism to construct the eigenstates and eigenenergies for Landau levels in noncommutative plane. General formulas for the spectrum of energies are deduced, for both cases, single and bilayer graphene. In both cases we find that the effect to introduce noncommutative coordinates is a shift in the energy spectrum with respect to result obtained in commutative space.
A multiple-parameter approach for short-term traffic flow prediction
Authors: Wang Xiaoquan , Li Wenjun , Yin Chaoying , Zeng Shaoyu , Liu Peng
Published: May 2021

This study proposes a short-term traffic flow prediction approach based on multiple traffic flow basic parameters, in which the chaos theory and support vector regression are utilized. First, a high-dimensional variable space can be obtained according to the traffic flow fundamental function. Then, a maximum conditional entropy method is proposed to determine the embedding dimension. And multiple time series are reconstructed based on the phase space reconstruction theory using the time delay obtained by mutual information method and the embedding dimension captured by the maximum conditional entropy method. Finally, the reconstructed phase space is used as the input and the support vector regression optimized by the genetic algorithm is utilized to predict the traffic flow. Numerical experiments are performed and the results show that the approach proposed has strong fitting capability and better prediction accuracy.
An overview of the taxonomic groups of non-pollen palynomorphs
Authors: Shumilovskikh Lyudmila , O'Keefe Jennifer M. K. , Marret Fabienne
Published: May 2021

Non-pollen palynomorphs (NPPs) are ‘extra’ microfossils often found in palynology slides. These include remains of organisms within the size range of pollen grains (
c.
10–250 µm), resistant to laboratory treatments used for the preparation of palynological samples. NPPs are a large and taxonomically heterogeneous group of remains of organisms living in diverse environments. Taxonomically, they belong to a wide variety of groups such as cyanobacteria, algae, vascular plants, invertebrates and fungi. The aim of this chapter is to provide a general overview of NPP groups observed in palynology slides. It includes more than 40 of the most common groups starting with acritarcha, cyanobacteria and algae, moving through transitional groups to animals and fungi and finishing with human-made objects such as textile fibres. Although far from complete, it provides an updated overview of taxonomical diversity of NPPs and their indicator values. Further works on NPP identifications are of great importance to improve our current knowledge. Since NPPs occur in all kinds of sediments, their analysis is a powerful tool for reconstructing environmental changes over time. Further detailed studies of specific NPP groups and their indicator values will open the way for new fields of study.
Cache Oblivious Algorithms for Computing the Triplet Distance between Trees
Authors: Brodal Gerth Stølting , Mampentzidis Konstantinos
Published: May 2021

We consider the problem of computing the triplet distance between two rooted unordered trees with
n
labeled leaves. Introduced by Dobson in 1975, the triplet distance is the number of leaf triples that induce different topologies in the two trees. The current theoretically fastest algorithm is an O(
n
log
n
) algorithm by Brodal et al. (SODA 2013). Recently, Jansson and Rajaby proposed a new algorithm that, while slower in theory, requiring O(
n
log
3
n
) time, in practice it outperforms the theoretically faster O(
n
log
n
) algorithm. Both algorithms do not scale to external memory.

We present two cache oblivious algorithms that combine the best of both worlds. The first algorithm is for the case when the two input trees are binary trees, and the second is a generalized algorithm for two input trees of arbitrary degree. Analyzed in the RAM model, both algorithms require O(
n
log
n
) time, and in the cache oblivious model O(
n
/
B
log
2
n
/
M
) I/Os. Their relative simplicity and the fact that they scale to external memory makes them achieve the best practical performance. We note that these are the first algorithms that scale to external memory, both in theory and in practice, for this problem.
Machine Learning for Detecting Data Exfiltration
Authors: Sabir Bushra , Ullah Faheem , Babar M. Ali , Gaire Raj
Published: May 2021

Context
: Research at the intersection of cybersecurity, Machine Learning (ML), and Software Engineering (SE) has recently taken significant steps in proposing countermeasures for detecting sophisticated data exfiltration attacks. It is important to systematically review and synthesize the ML-based data exfiltration countermeasures for building a body of knowledge on this important topic.
Objective
: This article aims at systematically reviewing ML-based data exfiltration countermeasures to identify and classify ML approaches, feature engineering techniques, evaluation datasets, and performance metrics used for these countermeasures. This review also aims at identifying gaps in research on ML-based data exfiltration countermeasures.
Method
: We used Systematic Literature Review (SLR) method to select and review 92 papers.
Results
: The review has enabled us to: (a) classify the ML approaches used in the countermeasures into data-driven, and behavior-driven approaches; (b) categorize features into six types: behavioral, content-based, statistical, syntactical, spatial, and temporal; (c) classify the evaluation datasets into simulated, synthesized, and real datasets; and (d) identify 11 performance measures used by these studies.
Conclusion
: We conclude that: (i) The integration of data-driven and behavior-driven approaches should be explored; (ii) There is a need of developing high quality and large size evaluation datasets; (iii) Incremental ML model training should be incorporated in countermeasures; (iv) Resilience to adversarial learning should be considered and explored during the development of countermeasures to avoid poisoning attacks; and (v) The use of automated feature engineering should be encouraged for efficiently detecting data exfiltration attacks.
Survey of Transient Execution Attacks and Their Mitigations
Authors: Xiong Wenjie , Szefer Jakub
Published: May 2021

Transient execution attacks, also known as speculative execution attacks, have drawn much interest in the last few years as they can cause critical data leakage. Since the first disclosure of Spectre and Meltdown attacks in January 2018, a number of new transient execution attack types have been demonstrated targeting different processors. A transient execution attack consists of two main components: transient execution itself and a covert channel that is used to actually exfiltrate the information.Transient execution is a result of the fundamental features of modern processors that are designed to boost performance and efficiency, while covert channels are unintended information leakage channels that result from temporal and spatial sharing of the micro-architectural components. Given the severity of the transient execution attacks, they have motivated computer architects in both industry and academia to rethink the design of the processors and to propose hardware defenses. To help understand the transient execution attacks, this survey summarizes the phases of the attacks and the security boundaries across which the information is leaked in different attacks.This survey further analyzes the causes of transient execution as well as the different types of covert channels and presents a taxonomy of the attacks based on the causes and types. This survey in addition presents metrics for comparing different aspects of the transient execution attacks and uses them to evaluate the feasibility of the different attacks. This survey especially considers both existing attacks and potential new attacks suggested by our analysis. This survey finishes by discussing different mitigations that have so far been proposed at the micro-architecture level and discusses their benefits and limitations.
A Survey on Causal Inference
Authors: Yao Liuyi , Chu Zhixuan , Li Sheng , Li Yaliang , Gao Jing , Zhang Aidong
Published: May 2021

Causal inference is a critical research topic across many domains, such as statistics, computer science, education, public policy, and economics, for decades. Nowadays, estimating causal effect from observational data has become an appealing research direction owing to the large amount of available data and low budget requirement, compared with randomized controlled trials. Embraced with the rapidly developed machine learning area, various causal effect estimation methods for observational data have sprung up. In this survey, we provide a comprehensive review of causal inference methods under the potential outcome framework, one of the well-known causal inference frameworks. The methods are divided into two categories depending on whether they require all three assumptions of the potential outcome framework or not. For each category, both the traditional statistical methods and the recent machine learning enhanced methods are discussed and compared. The plausible applications of these methods are also presented, including the applications in advertising, recommendation, medicine, and so on. Moreover, the commonly used benchmark datasets as well as the open-source codes are also summarized, which facilitate researchers and practitioners to explore, evaluate and apply the causal inference methods.
On the Impact of Sample Duplication in Machine-Learning-Based Android Malware Detection
Authors: Zhao Yanjie , Li Li , Wang Haoyu , Cai Haipeng , Bissyandé Tegawendé F. , Klein Jacques , Grundy John
Published: May 2021

Malware detection at scale in the Android realm is often carried out using machine learning techniques. State-of-the-art approaches such as DREBIN and MaMaDroid are reported to yield high detection rates when assessed against well-known datasets. Unfortunately, such datasets may include a large portion of duplicated samples, which may bias recorded experimental results and insights. In this article, we perform extensive experiments to measure the performance gap that occurs when datasets are de-duplicated. Our experimental results reveal that duplication in published datasets has a limited impact on supervised malware classification models. This observation contrasts with the finding of Allamanis on the general case of machine learning bias for big code. Our experiments, however, show that sample duplication more substantially affects unsupervised learning models (e.g., malware family clustering). Nevertheless, we argue that our fellow researchers and practitioners should always take sample duplication into consideration when performing machine-learning-based (via either supervised or unsupervised learning) Android malware detections, no matter how significant the impact might be.