bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on harmonic interaction between paralleled STATCOMs with cascaded H‐bridge topology in wind farm clusters
Authors: Chen Jikai , Hu Yang , Wang Yongquan , Li Jiang , Wang Xiaozhe , Jiang Qirong , Zheng Xuemei
Published: May 2021

To ensure reasonable reactive power distribution and voltage standard, a large number of STATCOMs are integrated to wind farms and afflux stations. However, the issue of device tripping caused by the interaction between STATCOMs is emerging. This paper sets out to bring a clear understanding of the fault mechanism of single STATCOM tripping caused by the harmonic circulation between STATCOMs in a clustered wind‐farm afflux station in North‐China grid. The equivalent circuit of harmonic circulation between two paralleled STATCOMs based on cascaded H‐bridge topology is established first. Thereafter, the intrinsic relationship between high‐order harmonic circulation and inter‐converter harmonic voltage difference as well as the phase deviation of SPWM carriers are analysed. A generalized model is also built to estimate the higher‐order harmonics. The impact of non‐characteristic harmonics on DC voltage of each H‐bridge cell is investigated by calculating the difference of active power flowing through DC capacitors. It is pointed out that the harmonic circulation is one of the main reasons resulting in the DC overvoltage protection action of STATCOM. Finally, the correctness of theoretical analysis is verified by real‐time simulation and hardware experiments.
A bi‐level model for co‐expansion planning of generation and energy storage system (ESS) with contract pricing
Authors: Rafiei Seyed Arash , Rafiei Seyed‐Reza , Goldani Saeedreza , Falaghi Hamid
Published: May 2021

In co‐expansion planning of generation and storage systems, the investor aims to determine the time, location, and capacity of the generation energy storage units. The main challenge is to install these systems in a way that the investor's profit is maximized. In addition, market‐clearing must take place in order to optimize social welfare. This paper studies a co‐expansion planning problem as a bi‐level model that involves the expansion of generation and energy storage units. Generating units include wind and gas turbines and the energy storage system (ESS) is compressed air. This paper addresses the upper‐level problem of increasing investor profits and the lower‐level problem of increasing social welfare. Simulation results show that an investor can achieve the highest possible profit by simultaneously investing in the wind and gas turbine as well as the storage systems using strategic behaviour (price offer/bid close to market price) and participating in the spot market and guaranteed purchase contract. In addition, improving the load growth rate and guaranteed purchase contracts increase the investment in the generation‐storage units. The simulation results of this study are compared with other studies for validation purposes.
A novel power management strategy based on combination of 3D droop control and EKF in DC microgrids
Authors: Sabzpoosh Saravi Vahid , Sakhaei Hossein , Kalantar Mohsen , Anvari‐Moghaddam Amjad
Published: May 2021

Voltage regulation and power management are necessary to maintain balance of supply and demand in DC microgrids. In such systems, power sharing is normally done through parallel operation of distributed energy resources equipped with droop controllers. However, low power sharing accuracy and not allowing the microgrid to maximise the available power from the renewable sources are two main problems associated with conventional droop control methods. In addition, the 2D droop method is a parameter‐dependent method for extracting maximum available energy from renewable sources. In this paper, a novel power management strategy based on the optimal 3D droop coefficients is developed for a DC microgrid. Optimal state estimation is attained using a combination of extended Kalman filter and adaptive recursive least square method. Reference currents of renewable energy sources (wind and solar) and battery energy storage system are estimated using the proposed prediction based model. The proposed strategy not only increases the power sharing accuracy but also remains the bus voltage around a nominal value. The performance of the proposed method is evaluated for the considered DC microgrid in two different scenarios. Results show the high effectiveness and robustness of the proposed method. It has been concluded that precise estimation of the sources reference currents and 3D droop coefficients are critical for optimal power management and bus voltage regulation in DC microgrids.
Rotors for wave energy conversion—Practice and possibilities
Authors: Ermakov Andrei , Ringwood John V.
Published: May 2021

This review studies some of the existing ideas which create a fundamentally new direction for wave energy converter (WEC) development, obtaining energy from the elliptical motion of particles in water waves using a rotor. The review focuses on three main aspects of rotor‐based WECs: experimental study of the developed prototypes, derivation and development of the mathematical models, and control effectors and philosophies for the proposed devices. The range of developed small scale prototypes and their experimental studies are presented. The shortcomings of the current mathematical and hydrodynamic models are identified, while an overview of the proposed and new possible control effectors and strategies is conducted. This allows us to see the state of the development of the different concepts and problems to be solved in bringing wave energy rotors to operational reality.
Active jamming recognition based on bilinear EfficientNet and attention mechanism
Authors: Xiao Yihan , Zhou Jingyi , Yu Yongzhi , Guo Limin
Published: May 2021

As electromagnetic environments are increasingly complex, there are more kinds of radar jamming signals. Active jamming recognition has problems of the low recognition accuracy and the high computational complexity, especially under a low jamming‐to‐noise ratio (JNR). Herein, a deep learning network based on bilinear EfficientNet and attention mechanism is proposed to recognise and classify eight kinds of jamming signals automatically. Firstly, the one‐dimensional interference signal is transformed into a two‐dimensional time–frequency image by the time–frequency analysis. Based on the transfer learning of EfficientNet‐B3, the effective features of the time–frequency image are automatically extracted by the two‐way network with attention mechanism, and the active interference classification is realised. The experimental results show that the method's overall recognition rate for eight kinds of interference signals is more than 97.5% when the JNR is −8 dB and is close to 100% at −2 dB.
Distributed battery energy storage systems operation framework for grid power levelling in the distribution networks
Authors: Raouf Mohamed Ahmed A. , Morrow D. John , Best Robert J. , Cupples Andrew , Bailie Ian , Pollock Jonathan
Published: May 2021

The integration of battery energy storage systems (BESS) in the electrical grid is accelerating to mitigate the challenges associated with the rapid deployment of low carbon technologies (LCTs). This work investigates the ability of BESS to provide the power networks with important ancillary services such as peak shaving and grid power levelling through two case studies conducted in collaboration with Northern Ireland's distribution network operator. A powerful approach consisting of two strategies is developed to operate the BESS powerfully to enhance the operation of the distribution network. The first strategy is day‐ahead scheduling that aims to dispatch the distributed BESS to smooth the grid power and mitigate voltage and lines stresses. A powerful demand forecasting algorithm is utilised to efficiently apply the day‐ahead scheduling. The second strategy is a real‐time operation to flatten the grid power which can be used separately or to adjust the results obtained from the day‐ahead strategy against the forecasting errors. The proposed approach was validated using real measurements and applied to an 11 kV distribution network located in Northern Ireland, UK. The BESS expected revenues from the participation in different services available in the island of Ireland are quantified and the degradation is considered.
Energy‐saving methods in pneumatic actuator stroke using compressed air
Authors: Jiang Zhong'ai , Xiong Wei , Du Hongwang , Wang Zhiwen , Wang Lu
Published: May 2021

The pneumatic systems have lower energy efficiency than the electric and hydraulic systems. Improving the utilisation rate of compressed air is an important aspect for increasing the energy efficiency in the pneumatic systems. This paper introduces two methods for reducing air consumption, including the quantitative air intake method and the optimisation of the air intake and exhaust duration method. The quantitative air intake method analyses the minimum air consumption volume in a specific pneumatic system based on the energy conservation theory. The optimisation of the air intake and exhaust duration method aims to find the best air intake and exhaust time schedule by the mathematical optimisation of the energy‐saving and system stability of the pneumatic systems. An experimental equipment was established to verify the theoretical results of the two methods. Based on the experimental results, this paper analyses the characteristics and accuracy of the two methods and discusses the applicability of mathematical optimisation under some different boundary conditions. The experimental results show that both of the two methods can effectively reduce the air consumption in the piston stretching‐out stroke and save 76% of the air consumption compared with continuous air intake during the whole stroke.
A computing resource scheduling strategy of massive IoT devices in the mobile edge computing environment
Authors: Pang Meiyu , Yao Xiaofeng , Geng Miao
Published: May 2021

Aiming at the problem of scheduling computing resources for massive Internet of Things (IoT) devices, this paper proposes a scheduling strategy model based on mobile edge computing for massive IoT computing resources. First, the application scenarios are defined, the task offloading model and queue model are constructed. Then, task urgency and BS energy are considered to determine the optimization goal. Next, wolf colony algorithm is used to improve pheromone calculation so that the ant colony algorithm converges faster and is not easy to fall into local optimum when adjusting the computing resources of IoT devices, and then realizes the scheduling strategy of massive IoT devices. Finally, the experimental verification and comparative analysis of our proposed method are carried out. Experimental results show that proposed method is superior to the method based on Game Theory (GT) and the method based on Sub‐Optimal Policy (SOP). Besides, the proposed method can offload more tasks under the same conditions. The average energy consumption of proposed method is lower in 60–240 GHz frequency band. Moreover, it appears to increase significantly in 60–120 GHz frequency band, and tends to be stable in 120–240 GHz frequency band.
A multi‐objective approach for improving real‐time audio peak reduction and speech clarity in a dental drill noise reduction device
Authors: Jiang Pingfei , Atherton Mark A.
Published: May 2021

Audio signals typically comprise several characteristics to be improved by signal processing and in practice, each of these characteristics has a unique relationship to the controllable system parameters. Quantifying these relationships in a multi‐objective (MO) approach will enable an improved system setup. This paper determines two novel objective functions of a complex audio signal for the real‐time simultaneous improvement of audio peak reduction and speech clarity in a dental drill noise reduction (DDNR) device. The influence of the DDNR system parameters on the outcome of peak reduction and speech clarity is determined by combining response surface methodology and a desirability function to enable MO optimisation. The results show an average improvement of nearly 30% over the original DDNR device performance. The approach described provides an effective means for addressing MO optimisation of other real‐time audio signal processing applications where the signal has similar peak reduction and speech clarity objectives to be processed, particularly where the physical outcome is not easy to evaluate in a virtual environment.
Is Exposure to Intrapartum Prostaglandins for Labor Induction Associated with a Lower Incidence of Neonatal Respiratory Distress Syndrome?
Authors: Son Shannon L. , Allshouse Amanda A. , Heinrichs Gretchen A. , Garite Thomas J. , Silver Robert M. , Wapner Ronald J. , Grobman William A. , Chung Judith H. , Mercer Brian M. , Metz Torri D.
Published: May 2021

Objective Respiratory distress syndrome (RDS) is implicated in 30% of neonatal deaths. Since prostaglandins promote surfactant secretion and labor is associated with a lower risk of RDS in term neonates, it is plausible that synthetic prostaglandin (sPG) exposure is associated with a lower risk of RDS. Thus, we evaluated the association between sPG exposure and RDS in neonates born after the induction of labor (IOL).

Study Design Secondary analysis of women with singleton pregnancies undergoing IOL at 340/7 to 420/7 weeks in the nuMoM2b study, a multicenter prospective cohort of nulliparous women. RDS rates and secondary neonatal outcomes in neonates with intrapartum sPG exposure were compared with those who had IOL with non-sPG methods (e.g., balloon catheter, amniotomy, oxytocin, and laminaria). Logistic regression models estimated the association of sPG with RDS and with secondary outcomes after adjustment for clinical and demographic factors (including gestational age). A sensitivity analysis was performed in which analysis was restricted to those with an admission cervical dilation ≤2 cm.

Results Of 10,038 women in the total cohort, 3,071 met inclusion criteria; 1,444 were exposed and 1,627 were unexposed to sPGs. Antenatal corticosteroid exposure rates were low (3.0%) and similar between groups. In univariable analysis, neonates with sPG exposure had higher rates of RDS (3.2 vs. 2.0%, odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.01–2.50). This relationship was similar by gestational age at delivery (term vs. preterm, interaction p = 0.14). After adjustment, the association between sPG and RDS was no longer significant (adjusted odds ratio: 1.4, 95% CI: 0.9–2.3). When analysis was restricted to subjects with admission cervical dilation of ≤2 cm, there was also no association between sPG exposure and RDS.

Conclusion In pregnancies between 34 and 42 weeks of gestation, exposure to sPG for cervical ripening or labor induction was not associated with newborn RDS.

Key Points
Pragmatic Experience with Risk-based versus Universal Hepatitis C Screening in Pregnancy: Detection of Infection and Postpartum Linkage to Care
Authors: Bushman Elisa T. , Subramani Lakshmi , Sanjanwala Aalok , Dionne-Odom Jodie , Franco Ricardo , Owen John , Subramaniam Akila
Published: May 2021

Objective Despite the Centers for Disease Control and Prevention (CDC) and U.S. Preventive Services Task Force (USPSTF) recommending universal hepatitis C virus (HCV) screening in pregnancy Society for Maternal-Fetal Medicine (SMFM) and American College of Obstetricians and Gynecologists (ACOG) continue to endorse risk-based screening for HCV in pregnancy. We hypothesized that universal screening is associated with increased HCV diagnosis and postpartum linkage to HCV care compared with risk-based screening.

Study Design This retrospective cohort study included pregnant women screened for HCV at a single tertiary-care center. We defined two cohorts: women managed with risk-based (January 2014–October 2016) or universal HCV screening (November 2016–December 2018). Screening was performed with ELISA antibody testing and viremia confirmed with HCV ribonucleic acid (RNA) polymerase chain reaction (PCR). Primary outcomes were the rate of HCV screen positivity and postpartum linkage to care.

Results From 2014 to 2018, 16,489 women delivered at our institution, of whom 166 screened positive for HCV. A total of 7,039 pregnant women were screened for HCV: 266 with risk-based and 6,773 with universal screening; 29% (76/266) were positive HCV antibody screening (HCVAb + ) in the risk-based cohort and 1.3% (90/6,773) in the universal cohort. HCVAb+ women in the risk-based cohort were more likely to have a positive drug screen. Only 69% (62/90) of HCVAb+ women in the universal cohort met the criteria for risk-based testing. Of the remaining 28 women, 6 (21%) had active viremia (HCV RNA+). Of the 166 HCVAb+ women, 64% (103/166) were HCV RNA+—51 of 266 (19%) in the risk-based and 52 of 6,773 (0.8%) in the universal cohort. Of HCVAb+ women, 75% (125/166) were referred postpartum for HCV evaluation and 27% (34/125) were linked to care. Only 9% (10/103) of women with viremia initiated treatment within 1 year of delivery.

Conclusion Universal HCV screening in pregnancy identified an additional 31% of HCVAb+ women compared with risk-based screening. Given low rates of HCV follow-up and treatment regardless of screening modality, further studies are needed to address barriers to postpartum linkage to care.

Key Points
Placenta Accreta Spectrum: Correlation between FIGO Clinical Classification and Histopathologic Findings
Authors: Aalipour Soroush , Salmanian Bahram , Fox Karin A. , Clark Steven Leigh , Shamshirsaz Amir A. , Asl Nazlisadat Meshinchi , Castro Eumenia C. , Erfani Hadi , Spinoza Jimmy , Nassr Ahmed , Belfort Michael A. , Shamshirsaz Alireza A.
Published: May 2021

Objective Placenta accreta spectrum (PAS) covers a wide spectrum of placental adherence/invasion with varied clinical significance. Histopathologic examination is considered the confirmatory gold standard, but is only obtained sometime after definitive treatment. The International Federation of Gynecology and Obstetrics (FIGO) has published a new clinical classification that can be assigned at delivery, and we aimed to investigate the association between this new FIGO classification and histopathology and also to assess its correlation with maternal outcomes.

Study Design We studied a retrospective cohort of 185 patients with histopathologically proven PAS managed at our referral center between September 2012 and January 2019. Two experienced surgeons retrospectively reviewed charts and assigned the FIGO grading based on findings reported at delivery. A third experienced reviewer adjudicated to determine the classification used for final analysis. Categorical outcomes were compared with the use of chi-squared and the Fisher exact test, as appropriate. A multivariate model was designed to adjust outcomes in different FIGO groups for the involvement of a formal multidisciplinary management team.

Results Among 185 patients, there were 41 (22%) placenta accreta, 44 (24%) placenta increta, and 100 (54%) placenta percreta on histopathology. The inter-rater reliability was found to be substantial with Kappa = 0.661 (p < 0.001), and 95% confidence interval (CI): 0.449–0.872. There was a significant association between all histopathology groupings and the FIGO clinical classification (p < 0.001). However, we found no association between FIGO classifications and maternal complications.

Conclusion The new FIGO clinical classification is strongly associated with histopathologic findings. A better understanding of the depth and extent of invasion as afforded by the clinical classification system will help standardize reporting and future research.

Key Points
Improving the Timely Delivery of Antihypertensive Medication for Severe Perinatal Hypertension in Pregnancy and Postpartum
Authors: Schneider Patrick , Lee King Patricia Ann , Keenan-Devlin Lauren , Borders Ann E.B.
Published: May 2021

Objective Sustained blood pressures ≥160/110 during pregnancy and the postpartum period require timely antihypertensive therapy. Hospital-level experiences outlining the efforts to improve timely delivery of care within 60 minutes have not been described. The objective of this analysis was to assess changes in care practices of an inpatient obstetrical health care team following the implementation of a quality improvement initiative for severe perinatal hypertension during pregnancy and the postpartum period.

Study Design In January 2016, NorthShore University HealthSystem Evanston Hospital launched a quality improvement initiative focusing on perinatal hypertension, as part of a larger, statewide quality initiative via the Illinois Perinatal Quality Collaborative. We performed a retrospective cohort study of all pregnant and postpartum patients with sustained severely elevated blood pressure (two severely elevated blood pressures ≤15 minutes apart) with baseline data from 2015 and data collected during the project from 2016 through 2017. Changes in clinical practice and outcomes were compared before and after the start of the project. Statistical process control charts were used to demonstrate process-behavior changes over time.

Results Comparing the baseline to the last quarter of 2017, there was a significant increase in the administration of medication within 60 minutes for severe perinatal hypertension (p <0.001). Implementation of a protocol for event-specific debriefing for each severe perinatal hypertension episode was associated with increased odds of the care team administering medication within 60 minutes of the diagnosis of severe perinatal hypertension (adjusted odds ratio 3.20, 95% confidence interval 1.73–5.91, p < 0.01).

Conclusion Implementation of a quality improvement initiative for perinatal hypertension associated with pregnancy and postpartum improved the delivery of appropriate and timely therapy for severely elevated blood pressures and demonstrated the impact of interdisciplinary communication in the process.

Key Points
Maternal and Neonatal Morbidity after Cesarean Delivery for Active Phase Arrest following Adoption of the Obstetric Care Consensus Guidelines
Authors: Jalloul Randa J. , Bury-Fiol Arlene , Ibarra Claudia J. , Chen Han-Yang , Sibai Baha M. , Ward Clara
Published: May 2021

Objective In an effort to reduce the primary cesarean delivery (CD) rate, the American College of Obstetricians and Gynecologists (ACOG) recommended new labor guidelines in 2014 that allow longer duration of labor times. There are little data on the impact of these guidelines on CD rates and pregnancy outcomes in a predominantly Hispanic population. This study aimed to compare the primary CD rates and maternal and neonatal outcomes in patients undergoing primary CD for arrest of labor before and after implementation of the 2014 guidelines.

Study Design This was a retrospective cohort study of term patients who underwent a CD for an arrest disorder between January 2011 and April 2017 at a county teaching hospital. Our primary outcome was the composite maternal and neonatal morbidities (CMM and CNM, respectively). Differences in the demographic and clinical characteristics, CMM, and CNM stratified by time period (pre- vs. postimplementation) were examined.

Results There were 4,976 deliveries in the study period: 525 (11%) underwent primary CD for arrest disorder; 298 (6%) prior to 2014, and 227 (5%) after 2014 (p = 0.62). There was no significant difference in the rate of CD between the two periods (13.4 vs. 13.3%, p = 0.81). In patients undergoing CD for arrest of dilation (n = 389), the CMM and CNM did not significantly change between both groups (63.3 vs. 56%, p = 0.15). In patients who had a CD for arrest of descent (n = 136), the rate of CMM significantly increased from 50 to 75% (p = 0.02) with no significant change in the CNM (13.2 vs. 20%, p = 0.3).

Conclusion Despite significant changes in labor management after the publication of the 2014 guidelines, our primary CD rate was not reduced, and we noticed an increase in CMM in patients who had CD for arrest of descent. A randomized controlled trial is needed to further evaluate the effect of these guidelines nationally.

Key Points
Food Insecurity in an Urban Pregnancy Cohort
Authors: Sullivan Kirby , St John Meghan , DeFranco Emily , Kelly Elizabeth
Published: May 2021

Objective Food insecurity is a prominent problem and has been implicated in adverse maternal and neonatal outcomes. This study aims to describe the food insecure population in an urban academic health center perinatal cohort.

Study Design We enrolled 451 postpartum inpatients at the University of Cincinnati Medical Center who completed a questionnaire and were then categorized as food insecure based on U.S. Department of Agriculture standardized survey questions. Generalized linear models estimated the relative influence of maternal characteristics on food insecurity.

Results Among the study population (n = 426), 18.6% (95% confidence interval: 15.2–22.4%) were classified as food insecure. Factors with increased adjusted relative risk on food insecurity include annual household income <$40,000, obesity, and smoking. Food insecure women also reported lower levels of love, satisfaction, and joy, and higher levels of despair.

Conclusion We recommend the use of a validated screening tool on all pregnant women with the associated psychosocial stressors and social determinants of health.

Key Points
From Pruritus to Cholestasis: Building a Statistical Model and Online Application to Predict a Diagnosis Prior to Bile Acid Determination
Authors: Ramirez Zamudio Andres F. , Monrose Erica , Pan Stephanie , Ferrara Lauren
Published: May 2021

Objective This study aimed to create a statistical model using clinical and laboratory parameters to predict which patients presenting with pruritus in pregnancy will have elevated total bile acids (TBA) and thus, have a high risk of intrahepatic cholestasis of pregnancy (ICP).

Study Design Retrospective cohort study of patients presenting with pruritus in pregnancy and had TBA sent from a single public hospital from January 1, 2017, to December 31, 2017. Primary outcome is TBA ≥ 10 µmol/L. Multivariate logistic regression with stepwise and backward variable selection were used to create predictive models. Four models were compared using Akaike information criterion (AIC), C-statistic, and the DeLong nonparametric approach to test for differences between area under the curve (AUC) of receiver operating characteristic (ROC) curves. Internal validation was performed via fivefold cross-validation technique on the best-fitting, most parsimonious model.

Results Of the 320 patients with pruritus, 153 (47.8%) had elevated bile acid levels ≥10 µmol/L. Sixty-nine variables were assessed for association with the primary outcome. Five variables were significantly associated with elevated TBA: pruritus of palms and soles (adjusted odds ratio [aOR]: 2.35 [95% confidence interval, CI: 1.22, 4.54]), gestational hypertension (aOR: 0.10 [95% CI: 0.02, 0.60]), log of total bilirubin (aOR: 4.71 [95% CI: 2.28, 9.75]), systolic blood pressure (aOR: 0.97 [95% CI: 0.94, 0.99]), and alanine aminotransferase (aOR: 1.05 [95% CI: 1.02, 1.07]). The final model was chosen for being parsimonious while having the lowest AIC with highest AUC (0.85; 95% CI: 0.81, 0.89). Internal validation using a probability threshold of 50% demonstrated a sensitivity of 65.5%, specificity of 83.5%, and accuracy of 75.1%.

Conclusion We provide a predictive model using five simple variables to determine the probability that a patient presenting with pruritus in pregnancy carries the diagnosis of ICP. This tool, available via a web app, is designed to aid providers and enhance clinical judgment in difficult triage situations.

Key Points
Obstetric Outcomes in Singleton Pregnancies with Abnormal Placental Cord Insertions
Authors: Zahedi-Spung Leilah D. , Stout Molly J. , Carter Ebony B. , Dicke Jeffrey M. , Tuuli Methodius G. , Raghuraman Nandini
Published: May 2021

Objective There is wide variation in the management of pregnancies complicated by abnormal placental cord insertion (PCI), which includes velamentous cord insertion (VCI) and marginal cord insertion (MCI). We tested the hypothesis that abnormal PCI is associated with small for gestational age (SGA) infants.

Study Design This is a retrospective cohort study of all pregnant patients undergoing anatomic ultrasound at a single institution from 2010 to 2017. Patients with abnormal PCI were matched in a 1:2 ratio by race, parity, gestational age at the time of ultrasound, and obesity to patients with normal PCIs. The primary outcome was SGA at delivery. Secondary outcomes were cesarean delivery, preterm delivery, cesarean delivery for nonreassuring fetal status, 5-minute Apgar score < 7, umbilical artery pH < 7.1, and neonatal intensive care unit admission. These outcomes were compared using univariate and bivariate analyses.

Results Abnormal PCI was associated with an increased risk of SGA (relative risk [RR]: 2.43; 95% confidence interval [CI]: 1.26–4.69), increased risk of preterm delivery <37 weeks (RR: 3.60; 95% CI: 1.74–7.46), and <34 weeks (RR: 3.50; 95% CI: 1.05–11.63) compared with patients with normal PCI. There was no difference in rates of cesarean delivery, Apgar score of <7 at 5 minutes, acidemia, or neonatal intensive care unit admission between normal and abnormal PCI groups. In a stratified analysis, the association between abnormal PCI and SGA did not differ by the type of abnormal PCI (p for interaction = 0.46).

Conclusion Abnormal PCI is associated with an increased risk of SGA and preterm delivery. These results suggest that serial fetal growth assessments in this population may be warranted.

Key Points
Traditional use of field burning in Ireland: history, culture and contemporary practice in the uplands
Authors: Carroll Matthew S. , Edgeley Catrin M. , Nugent Ciaran
Published: May 2021

Fire use is increasingly recognised as a central component of integrated land management in fire-prone places. Historically, fire use has been commonplace in many places in Ireland, where field burning is an established practice with a long pedigree among upland farmers seeking to improving forage among other benefits. This practice has been subject to controversy as wildfires – a hazard often associated with upland burning practice – continue to gain public attention and concern. This research seeks to understand the practice of field burning from the viewpoint of practitioners themselves through focus groups with upland burners conducted in a variety of locations across Ireland. Discussions focused on the history of field burning, reasons for its use, and how knowledge of the techniques involved in burning has been passed down through generations. The narrative that emerges is that of a critical livelihood-supporting practice steeped in social and ecological value but threatened by stringent regulation and shifting public opinion. We suggest that one way to preserve this practice may be to establish more formal linkages between fire use practitioners and Ireland’s fire services, public land managers and regulators to promote appropriate use of traditional fire within modern legal and best practice frameworks.
Raoiella indica (red palm mite).
Authors: Taylor Bryony
Published: May 2021

R. indica was first described in India in 1924 (Hirst) and has since been reported in several Old World countries. The species became of recent significance in 2004 when it was first reported in the Caribbean (Flechtmann and Étienne, 2004). Since then the mite has successfully spread throughout the islands of the Caribbean and has expanded its range into southern Florida (USDA-APHIS, 2007), South America (northern Venezuela, Vásquez et al., 2008; Brazil, Navia et al., 2010; Colombia, Carrillo et al., 2011) and Mexico (Estrada-Venegas et al., 2010). The mite has been reported on a wide range of palm hosts of the family Arecaceae and apparent new associations with members of the order Zingiberales, including the families Musaceae, Heliconiaceae, Zingiberaceae and Strelitziaceae have been reported. The success of the mite in the invasive range may be attributed to its ability to colonize many different host plant species, its apparent lack of co-evolved natural enemies in its new habitat and its rapid dispersal in its new range.
Using bioprinting and spheroid culture to create a skin model with sweat glands and hair follicles
Authors: Zhang Yijie , Enhejirigala  , Yao Bin , Li Zhao , Song Wei , Li Jianjun , Zhu Dongzhen , Wang Yuzhen , Duan Xianlan , Yuan Xingyu , Huang Sha , Fu Xiaobing
Published: May 2021

Background

Sweat glands (SGs) and hair follicles (HFs) are two important cutaneous appendages that play crucial roles in homeostatic maintenance and thermoregulation, and their interaction is involved in wound healing. SGs can be regenerated from mesenchymal stem cell-laden 3D bioprinted scaffolds, based on our previous studies, whereas regeneration of HFs could not be achieved in the same model. Due to the lack of an in vitro model, the underlying molecular mechanism of the interaction between SGs and HFs in regeneration could not be fully understood. The purpose of the present study was to establish an in vitro model of skin constructs with SGs and HFs and explore the interaction between these two appendages in regeneration.

Methods

To investigate the interaction effects between SGs and HFs during their regeneration processes, a combined model was created by seeding HF spheroids on 3D printed SG scaffolds. The interaction between SG scaffolds and HF spheroids was detected using RNA expression and immunofluorescence staining. The effects of microenvironmental cues on SG and HF regeneration were analysed by altering seed cell types and plantar dermis homogenate in the scaffold.

Results

According to this model, we overcame the difficulties in simultaneously inducing SG and HF regeneration and explored the interaction effects between SG scaffolds and HF spheroids. Surprisingly, HF spheroids promoted both SG and HF differentiation in SG scaffolds, while SG scaffolds promoted SG differentiation but had little effect on HF potency in HF spheroids. Specifically, microenvironmental factors (plantar dermis homogenate) in SG scaffolds effectively promoted SG and HF genesis in HF spheroids, no matter what the seed cell type in SG scaffolds was, and the promotion effects were persistent.

Conclusions

Our approach elucidated a new model for SG and HF formation in vitro and provided an applicable platform to investigate the interaction between SGs and HFs in vitro. This platform might facilitate 3D skin constructs with multiple appendages and unveil the spatiotemporal molecular program of multiple appendage regeneration.
Conducting correlation analysis: important limitations and pitfalls
Authors: Janse Roemer J , Hoekstra Tiny , Jager Kitty J , Zoccali Carmine , Tripepi Giovanni , Dekker Friedo W , van Diepen Merel
Published: May 2021

The correlation coefficient is a statistical measure often used in studies to show an association between variables or to look at the agreement between two methods. In this paper, we will discuss not only the basics of the correlation coefficient, such as its assumptions and how it is interpreted, but also important limitations when using the correlation coefficient, such as its assumption of a linear association and its sensitivity to the range of observations. We will also discuss why the coefficient is invalid when used to assess agreement of two methods aiming to measure a certain value, and discuss better alternatives, such as the intraclass coefficient and Bland–Altman’s limits of agreement. The concepts discussed in this paper are supported with examples from literature in the field of nephrology.
Cybersecurity of consumer products against the background of the EU model of cyberspace protection
Authors: Banasiński Cezary , Rojszczak Marcin
Published: May 2021

The entry into force of Regulation 2019/881 heralded a new stage in the construction of the EU cybersecurity model. At present, at the level of both EU institutions and individual Member States, preparatory work is underway to create the first ICT certification programmes relating to the area of cybersecurity. To date, the role of national competition and consumer protection authorities in helping to build a coherent cybersecurity model has not been sufficiently highlighted. The problem of the cybersecurity of products intended for the consumer market is a pressing issue. Furthermore, its significance is growing due in no small part to the increasing number of so-called smart connected consumer products and the mass expansion of the IoT market. As a result, threats to security or privacy increasingly stem not from cyberattacks on leading providers of online services but from the exploitation of vulnerabilities in commonly-used consumer products. This article aims to discuss the possible role of competition and consumer protection authorities in shaping a future model of EU cybersecurity. We discuss the existing mechanisms in EU law that allow supervisory authorities to shape the consumer product safety market and consider whether these measures can also be considered adequate for cybersecurity purposes. Particular attention is paid to identifying what legislative steps would be necessary to effectively synthesize the new EU cybersecurity regulations (including the planned cybersecurity certification framework) with existing consumer product safety laws.
Safety and acute efficacy of cryoballoon ablation for atrial fibrillation at community hospitals
Authors: Hoffmann Rainer , Parade Ulli , Bauerle Hansjörg , Winter Klaus-Dieter , Rauschenbach Ulrich , Mischke Karl , Schaefer Carl , Gutleben Klaus-Jürgen , Rana Obaida R , Willich Tobias , Schlößer Marc , Rötzer Alfons , Breithardt Ole A , Middendorf Stefan , Waldecker Berndt , Grove Rainer , Mosa Jörg , Krug Joachim , Imnadze Guram , Saygili Erol , Michaelsen Jochen
Published: May 2021

Aims

Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) is an established procedure for treating symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI performed at community hospitals are unknown. We aimed to determine the safety and acute efficacy of PVI using CBA performed at community hospitals with limited annual case numbers.

Methods and results

This registry study included 1004 consecutive patients who had PVI performed for symptomatic paroxysmal (n = 563) or persistent AF (n = 441) from January 2019 to September 2020 at 20 hospitals. Each hospital performed fewer than 100 CBA–PVI procedures/year according to local standards. Procedural data, efficacy, and complication rates were determined. The mean number of CBA procedures performed/year at each centre was 59 ± 25. The average procedure time was 90.1 ± 31.6 min and the average fluoroscopy time was 19.2 ± 11.4 min. Isolation of all pulmonary veins was documented in 97.9% of patients. The most frequent reason for not achieving complete isolation was development of phrenic nerve palsy. No hospital deaths were observed. Two patients (0.2%) suffered a clinical stroke. Pericardial effusion occurred in six patients (0.6%), two of whom (0.2%) required pericardial drainage. Vascular complications occurred in 24 patients (2.4%), two of whom (0.2%) required vascular surgery. Phrenic nerve palsy occurred in 48 patients (4.8%) and persisted up to hospital discharge in six patients (0.6%).

Conclusion

Pulmonary vein isolation procedures for paroxysmal or persistent AF using CBA can be performed at community hospitals with high acute efficacy and low complication rates.
shrunken4 is a mutant allele of ZmYSL2 that affects aleurone development and starch synthesis in maize
Authors: He Yonghui , Yang Qing , Yang Jun , Wang Yong-Fei , Sun Xiaoliang , Wang Shu , Qi Weiwei , Ma Zeyang , Song Rentao
Published: May 2021

Minerals are stored in the aleurone layer and embryo during maize seed development, but how they affect endosperm development and activity is unclear. Here, we cloned the gene underlying the classic maize kernel mutant shrunken4 (sh4) and found that it encodes the YELLOW STRIPE-LIKE oligopeptide metal transporter ZmYSL2. sh4 kernels had a shrunken phenotype with developmental defects in the aleurone layer and starchy endosperm cells. ZmYSL2 showed iron and zinc transporter activity in Xenopus laevis oocytes. Analysis using a specific antibody indicated that ZmYSL2 predominately accumulated in the aleurone and sub-aleurone layers in endosperm and the scutellum in embryos. Specific iron deposition was observed in the aleurone layer in wild-type kernels. In sh4, however, the outermost monolayer of endosperm cells failed to accumulate iron and lost aleurone cell characteristics, indicating that proper functioning of ZmYSL2 and iron accumulation are essential for aleurone cell development. Transcriptome analysis of sh4 endosperm revealed that loss of ZmYSL2 function affects the expression of genes involved in starch synthesis and degradation processes, which is consistent with the delayed development and premature degradation of starch grains in sh4 kernels. Therefore, ZmYSL2 is critical for aleurone cell development and starchy endosperm cell activity during maize seed development.
Adding Nuance to Our Understanding of Dog–Wildlife Interactions and the Need for Management
Authors: Gompper Matthew E
Published: May 2021

Synopsis

The interactions of dogs and wildlife are receiving increasing attention across the globe. Evidence suggests that dogs can negatively affect wildlife in a variety of ways, including through the risk of predation, by hybridizing with other Canis species, by acting as a reservoir or vector of pathogens, and by competing with wildlife for resources. A multitude of observations and case studies for each of these interactions has led to calls to prioritize increased management of dogs, for instance, through population reduction, vaccination, movement restrictions, and enhanced care of the dogs themselves. Here, I argue that while the risks that dogs present to wildlife are real, they vary in their importance across the globe. Furthermore, often the approaches used to address these risks are championed without a full understanding of the likelihood of success given the necessary spatial scale of management, the availability of alternative management approaches, and the role dogs play in societies. For instance, culling, vaccination, and animal husbandry approaches in reducing the impacts of dogs on wildlife sometimes fail to recognize that local human populations actively recruit replacement dogs, that vaccination often fails to reach levels necessary for herd immunity, and that enhanced dog husbandry may have indirect impacts on wildlife by requiring environmentally impactful activities. I suggest there is a need for attention not only to identify the impacts of dogs but also to determine where and when such interactions with wildlife are problematic and the likelihood of success for any proposed management approach. The impacts of dogs should be mediated in a context-specific manner that accounts for factors such as the local density of dogs, the susceptibility of local wildlife populations to the risks that dog populations may represent, and the local societal norms that underpin how dogs might be managed.
Estimating location parameters in sample-heterogeneous distributions
Authors: Pensia Ankit , Jog Varun , Loh Po-Ling
Published: May 2021

Estimating the mean of a probability distribution using i.i.d. samples is a classical problem in statistics, wherein finite-sample optimal estimators are sought under various distributional assumptions. In this paper, we consider the problem of mean estimation when independent samples are drawn from $d$-dimensional non-identical distributions possessing a common mean. When the distributions are radially symmetric and unimodal, we propose a novel estimator, which is a hybrid of the modal interval, shorth and median estimators and whose performance adapts to the level of heterogeneity in the data. We show that our estimator is near optimal when data are i.i.d. and when the fraction of ‘low-noise’ distributions is as small as $\varOmega \left (\frac{d \log n}{n}\right )$, where $n$ is the number of samples. We also derive minimax lower bounds on the expected error of any estimator that is agnostic to the scales of individual data points. Finally, we extend our theory to linear regression. In both the mean estimation and regression settings, we present computationally feasible versions of our estimators that run in time polynomial in the number of data points.
Global epidemiology of Giardia duodenalis infection in cancer patients: a systematic review and meta-analysis
Authors: Mahdavi Farzad , Sadrebazzaz Alireza , Chahardehi Amir Modarresi , Badali Roya , Omidian Mostafa , Hassanipour Soheil , Asghari Ali
Published: May 2021

Background

Application of chemotherapeutics in cancer patients may provide an immunosuppressive milieu, favourable for parasitic infections. Giardia duodenalis is an important zoonotic intestinal parasite responsible for diarrhoea in humans worldwide.

Methods

The present systematic review and meta-analysis was conducted to estimate the prevalence of G. duodenalis and respective odds ratios (ORs) in cancer patients around the globe. Four online databases—PubMed, Scopus, Web of Science and Google Scholar—were carefully explored for relevant literature without time limitation until 28 November 2020. Meta-analysis was done based on a random effects model to pool the estimations and define 95% confidence intervals (CIs).

Results

The overall weighted prevalence of G. duodenalis infection in cancer patients was calculated to be 6.9% (95% CI 0.5 to 9.3) globally, based on data from 32 studies. Although not statistically significant, eight case–control studies revealed that cancer patients were 1.24 times (95% CI 0.66 to 2.31; p=0.501) more exposed to G. duodenalis infection than healthy controls. Moreover, the prevalence of infection was not significantly associated with quantitative variables, including publication year (regression coefficient −0.0135, p=0.578), sample size (regression coefficient −0.0007, p=0.074) and human development index (regression coefficient −1.6263, p=0.419). Also, subgroup analysis of the pooled G. duodenalis infection was performed for publication year, World Health Organization regions, countries, continents, cancer types and country income.

Conclusions

Altogether, the epidemiology of G. duodenalis infection and its associated risk factors in immunocompromised individuals, especially cancer patients, is still open to question and deserves comprehensive investigations.