bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel and simplified implementation of digital high-power pulsed MIG welding power supply with LLC resonant converter
Authors: Wu Kaiyuan , Huang Hao , Chen Ziwei , Zeng Min , Yin Tong
Published: September 2022

Purpose

This paper aims to overcome the limitations of low efficiency, low power density and strong electromagnetic interference (EMI) of the existing pulsed melt inert gas (MIG) welding power supply. So a novel and simplified implementation of digital high-power pulsed MIG welding power supply with LLC resonant converter is proposed in this work.

Design/methodology/approach

A simple parallel full-bridge LLC resonant converter structure is used to design the digital power supply with high welding current, low arc voltage, high open-circuit voltage and a wide range of arc loads, by effectively exploiting the variable load and high-power applications of LLC resonant converter.

Findings

The efficiency of each converter can reach up to 92.3%, under the rated operating condition. Notably, with proposed scheme, a short-circuit current mutation of 300 A can stabilize at 60 A within 8 ms. Furthermore, the pulsed MIG welding test shows that a stable welding process with 280 A peak current can be realized and a well-formed weld bead can be obtained, thereby verifying the feasibility of LLC resonant converter for pulsed MIG welding power supply.

Originality/value

The high efficiency, high power density and weak EMI of LLC resonant converter are conducive to the further optimization of pulsed MIG welding power supply. Consequently, a high performance welding power supply is implemented by taking adequate advantages of LLC resonant converter, which can provide equipment support for exploring better pulsed MIG welding processes.
Sliding mode predictive control of a five-level rectifier with only four–IGBT
Authors: Zhu Yifeng , Zhang Ziyang , Zhao Hailong , Li Shaoling
Published: September 2022

Purpose

Five-level rectifiers have received widespread attention because of their excellent performance in high-voltage and high-power applications. Taking a five-level rectifier with only four-IGBT for this study, a sliding mode predictive control (SMPC) algorithm is proposed to solve the problem of poor dynamic performance and poor anti-disturbance ability under the traditional model predictive control with the PI outer loop.

Design/methodology/approach

First, mathematical models under the two-phase stationary coordinate system and two-phase synchronous rotating coordinate system are established. Then, the design of the outer-loop sliding mode controller is completed by establishing the sliding mode surface and design approach rate. The design of the inner-loop model predictive controller was completed by discretizing the mathematical model equations. The modulation part uses a space vector modulation technique to generate the PWM wave.

Findings

The sliding mode predictive control strategy is compared with the control strategy with a PI outer loop and a model predictive inner loop. The proposed control strategy has a faster dynamic response and stronger anti-interference ability.

Originality/value

For the five-level rectifier, the advantages of fast dynamic influence and parameter insensitivity of sliding mode control are used in the voltage outer loop to replace the traditional PI control, and which is integrated with the model predictive control used in the current inner loop to form a novel control strategy with a faster dynamic response and stronger immunity to disturbances. This novel strategy is called sliding mode predictive control (SMC).
Fintech use, digital divide and financial inclusion
Authors: Odei-Appiah Solomon , Wiredu Gamel , Adjei Joseph Kwame
Published: September 2022

Purpose

Financial Technology (FinTech) innovations enable the provision of financial services to many unbanked across the world by increasing access. The key role of FinTech to drive financial inclusion however suffers significant impediments including the digital divide. Nevertheless, there is paucity of elaborate theories on financial inclusion while extant literature on FinTech only identify factors that drive its acceptance and use with little attention to inhibitors such as the digital divide. This study aims to investigate the impact of FinTech usage on financial inclusion amid the digital divide.

Design/methodology/approach

This study uses the unified theory of acceptance and use of technology (UTAUT2) and the model of digital inequality. A structural equation modeling technique is applied to data collected from 282 respondents in an online survey.

Findings

The findings confirm a positive influence of FinTech use on financial inclusion as well as the influence of performance expectancy and facilitating conditions on behavioral intentions. The results also show that digital divide measured with access, resource and force moderate the use of FinTech.

Originality/value

This study presents a theoretical model which is unique given that UTAUT2 was combined with digital divide moderators from the model of digital inequality to explain how FinTech usage impacts on financial inclusion. Addressing the research questions has led several theoretical contributions including the extension of the applicability of UTAUT2.
Design for safety in the construction industry: a study of architecture and engineering firms in Saudi Arabia
Authors: Hassanain Mohammad A. , Al-Harogi Mohammed , Sanni-Anibire Muizz O.
Published: September 2022

Purpose

This research aims to examine the practice of design for safety (DfS) in the construction industry of Saudi Arabia.

Design/methodology/approach

The study has adopted a mixed-method approach through the use of questionnaire surveys administered to professionals in architecture and engineering firms, as well as follow-up interviews with selected participants. The participants consisted of architects, structural engineers and electromechanical engineers. The study investigated dimensions related to knowledge and awareness, attitude toward DfS implementation and critical success factors for DfS implementation. These various dimensions have been assessed accordingly through the mean ratings in the relevant section of this paper. The thematic responses obtained from the follow-up interviews have been summarized and presented.

Findings

The findings from this study reveal a high level of awareness of DfS in Saudi Arabia. It also revealed that the most influential critical success factors are legislation and awareness of stakeholders, whereas the major barrier is the fear of cost overruns by the clients and their representatives.

Originality/value

The design stage of construction projects is crucial to enhancing the safety performance of projects through effective control of hazardous situations. The concept of DfS is, however, immature in many countries, such as Saudi Arabia, due to lack of awareness, enabling policies and other barriers. The value of this study is that it shows the current level of knowledge and practice of DfS in architecture and engineering firms in Saudi Arabia and consequently triggers the interest of stakeholders in its adoption and implementation.
Performance drivers in Iberian companies in different economic cycles: new evidence using panel data
Authors: Neves Maria Elisabete , Cancela Beatriz Lopes , Gabriel Vítor Manuel de Sousa
Published: September 2022

Purpose

This study aims to understand which factors determine the corporate performance of Portuguese and Spanish listed companies between 2011 and 2018, also considering the sub-period marked by the presence of the Troika in Portugal, between 2011 and 2014.

Design/methodology/approach

To achieve this aim, panel data methodology was used, specifically the generalized method of moments (GMM) estimation method proposed by Arellano and Bond (1991), Arellano and Bover (1995) and Blundell and Bond (1998) for 110 non-financial companies from the Iberian Peninsula.

Findings

The results point out different signs and significance of the variables in the companies of the two countries. Regarding the sub-period, our results suggest that the intervention of the Troika in Portugal acted in a very different way from the neighboring country.

Originality/value

This research shows the importance of studying countries individually, even with small dimensions, to reinforce the path that is still necessary for more sustainable companies. Furthermore, when companies have strong governance structures, the harmful contagion from one neighboring country to another may not happen.
Drivers of climate variability and increasing water salinity impacts on the farmer’s income risk with future outlook mitigation
Authors: Khan Arshad Ahmad , Khan Sufyan Ullah , Ali Muhammad Abu Sufyan , Khan Aftab , Hayat Yousaf , Luo Jianchao
Published: September 2022

Purpose

The main aim of this study is to investigate the impact of climate change and water salinity on farmer’s income risk with future outlook mitigation. Salinity and climate change are a threat to agricultural productivity worldwide. However, the combined effects of climate change and salinity impacts on farmers' income are not well understood, particularly in developing countries.

Design/methodology/approach

The response-yield function and general maximum entropy methods were used to predict the impact of temperature, precipitation and salinity on crop yield. The target minimization of total absolute deviations (MOTAD)-positive mathematical programming model was used to simulate the impact of climate change and salinity on socioeconomic and environmental indicators. In the end, a multicriteria decision-making model was used, aiming at the selection of suitable climate scenarios.

Findings

The results revealed that precipitation shows a significantly decreasing trend, while temperature and groundwater salinity (EC) illustrate a significantly increasing trend. Climate change and EC negatively impact the farmer's income and water shadow prices. Maximum reduction in income and water shadow prices was observed for A2 scenario (−12.4% and 19.4%) during 2050. The environmental index was the most important, with priority of 43.4% compared to socioeconomic indicators. Subindex amount of water used was also significant in study area, with 28.1% priority. The technique for order preference by similarity to ideal solution ranking system found that B1 was the best climatic scenario for adopting climate change adaptation in the research region.

Originality/value

In this study, farmers' income threats were assessed with the aspects of different climate scenario (A1, A1B and B1) over the horizons of 2030, 2040 and 2050 and three different indicators (economic, social and environmental) in Northwestern region of Pakistan. Only in arid and semiarid regions has climate change raised temperature and reduced rainfall, which are preliminary symptoms of growing salinity.
The past of tourist behaviour in hospitality and tourism in difficult times: a systematic review of literature (1978–2020)
Authors: Çakar Kadir , Aykol Şehmus
Published: September 2022

Purpose

The purpose of this study is to fill a gap in literature with a meta-analysis of previous studies assessing the decision-making processes of travellers when choosing holiday destinations in times of crisis.

Design/methodology/approach

This study presents here an abductive analysis of the findings of 737 peer-reviewed studies published in leading hospitality and tourism journals between 1978 and 2020. The studies in question concentrate on tourist typologies and behaviours when making destination choices in times of crisis, and the garnered data was subjected to a computer-aided data analysis adopting a thematic analysis technique, making use of Leximancer software.

Findings

The data was subjected to a thematic analysis and clustered under five main categories based on the distribution of articles by publication year, research topic, author contributions, articles by journal and articles by country (e.g. tourist typology, travellers’ decision-making, holiday decision-making, tourist decision-making, destination choice, traveller behaviour and vacation decision-making).

Research limitations/implications

The limitations of this study include its inclusion only of articles listed in the SCOPUS, Web of Science and ScienceDirect databases. This study makes a critical assessment of the current gaps in literature and proposes questions to be raised in future studies.

Originality/value

This study proposes several topics for future investigation that are considered necessary to close crucial gaps in our understanding of the tourism sector’s response to behavioural trends. The authors’ intention in this regard is to increase the scholarly awareness of decision-making models relevant to destination choice by linking tourist typologies and the behaviour exhibited before, during and after crises.
News coverage vs sentiment: evaluating German residential real estate markets
Authors: Ploessl Franziska , Just Tobias
Published: September 2022

Purpose

To investigate whether additional information of the permanent news flow, especially reporting intensity, can help to increase transparency in housing markets, this study aims to examine the relationship between news coverage or news sentiment and residential real estate prices in Germany at a regional level.

Design/methodology/approach

Using methods in the field of natural language processing, in particular word embeddings and dictionary-based sentiment analyses, the authors derive five different sentiment measures from almost 320,000 news articles of two professional German real estate news providers. These sentiment indicators are used as covariates in a first difference fixed effects regression to investigate the relationship between news coverage or news sentiment and residential real estate prices.

Findings

The empirical results suggest that the ascertained news-based indicators have a significant positive relationship with residential real estate prices. It appears that the combination of news coverage and news sentiment proves to be a reliable indicator. Furthermore, the extracted sentiment measures lead residential real estate prices up to two quarters. Finally, the explanatory power increases when regressing on prices for condominiums compared with houses, implying that the indicators may rather reflect investor sentiment.

Originality/value

To the best of the authors’ knowledge, this is the first paper to extract both the news coverage and news sentiment from real estate-related news for regional German housing markets. The approach presented in this study to quantify additional qualitative data from texts is replicable and can be applied to many further research areas on real estate topics.
Organizational resilience through techno-structural interventions: case of an Indian wealth management firm
Authors: Hassan Yusuf , Kushwaha Ankur , Sharma Varun
Published: September 2022

Purpose

The purpose of the current study is to examine organizational crisis and the role of tech-structural interventions in overcoming the crisis to achieve resilience. Developing resilience in organizations has become imperative for managers in the never-ending turbulent environment and concerns toward pleasing the stakeholders. Organizations have begun to rely on techno-structural and human process change interventions to attain resilient organizations. Although such strategies are widely prevalent in organizational change literature and can be traced back to the 1970s, scholarly research on the process that develops resilient organizations is limited and also absent in the context of developing economies.

Design/methodology/approach

This study uncovered the process of change interventions (primarily techno-structural interventions) at a wealth management firm in India, adopting a case study approach.

Findings

According to the findings, change interventions through techno-structural interventions aided in the transformation of a precarious organization into a resilient one.

Research limitations/implications

This paper provides vital practical implications about the role of techno-structural change interventions in reshaping an organization into a more viable business, making the organization resilient to deal with untimely disruptions in the environment.

Originality/value

Very limited research has been done to understand the stakeholder’s management and resilience in the context of financial consulting firms in the emerging market context.
Estimation of stress–strength reliability for inverse exponentiated distributions with application
Authors: Kumari Rani , Lodhi Chandrakant , Tripathi Yogesh Mani , Sinha Rajesh Kumar
Published: September 2022

Purpose

Inferences for multicomponent reliability is derived for a family of inverted exponentiated densities having common scale and different shape parameters.

Design/methodology/approach

Different estimates for multicomponent reliability is derived from frequentist viewpoint. Two bootstrap confidence intervals of this parametric function are also constructed.

Findings

Form a Monte-Carlo simulation study, the authors find that estimates obtained from maximum product spacing and Right-tail Anderson–Darling procedures provide better point and interval estimates of the reliability. Also the maximum likelihood estimate competes good with these estimates.

Originality/value

In literature several distributions are introduced and studied in lifetime analysis. Among others, exponentiated distributions have found wide applications in such studies. In this regard the authors obtain various frequentist estimates for the multicomponent reliability by considering inverted exponentiated distributions.
Influence of dimple textures on the tribological performances of tapered roller bearings under starved lubrication
Authors: Wang Yueyong , Zhang Yimin
Published: September 2022

Purpose

The purpose of this paper is to study the influence of dimple textures on the friction and wear properties of tapered roller bearings (TRBs) with many pattern parameters, e.g. diameter, depth and area density under starved lubrication.

Design/methodology/approach

The pattern parameters include the dimple diameter (D; 60, 100 and 200 µm), dimple depth (H; 5, 10 and 20 µm) and area density (S; 6%, 12% and 24%). Dimples were fabricated on the outer ring (OR) of TRBs using a laser marking machine. The tribological properties of dimple-textured TRBs under starved lubrication were studied on a vertical universal friction wear tester with special friction pairs. The effect mechanisms of dimple textures on the tribological properties of TRBs are presented and summarized through experiments and discussions.

Findings

When dimple-textured TRBs revolve under starved lubrication, the average coefficients of friction (ACOF) and wear losses are markedly lower than those of non-textured bearings.Shas the greatest influence on the COF curve. WhenDis 100 µm andSis 24%, the ACOF and wear losses are both lowest, i.e. 0.00426 and 0.51 mg, respectively. Under the same test conditions, compared with the non-textured group, its COF and wear loss decreased by 35.6% and 62.5%, respectively.

Originality/value

This work provides a useful reference for the research on the raceways of textured TRBs.
Effect of Mg addition on microstructure and mechanical properties of AlSi12 alloy produced by high-pressure casting method
Authors: Aksoy Samet , Kabakcı Fikret , Acarer Mustafa , Düzcükoğlu Hayrettin , Ünüvar Erdem , Fındık Fehim
Published: September 2022

Purpose

Paper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads.

Design/methodology/approach

AlSi12 alloys are used to manufacture the compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition.

Findings

AlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg2Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content.

Originality/value

In this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.
Relational leadership and employee creativity: the role of knowledge-sharing behaviour and leader–follower dyadic tenure
Authors: Ansong Abraham , Ennin Ethel Esi , Yeboah Moses Ahomka
Published: September 2022

Purpose

The study investigated the effects of relational leadership on hotel employees' creativity, using knowledge-sharing behaviour and leader–follower dyadic tenure as intervening variables.

Design/methodology/approach

A self-administered questionnaire was used to collect data from 355 employees of authorized hotels from the conurbation of Cape Coast and Elmina in Ghana. To evaluate the study's research hypotheses, the authors used WarpPLS and PLS-SEM.

Findings

The findings demonstrated that while knowledge-sharing behaviour did not directly affect employee creativity, it did have a significant mediating effect on the link between relational leadership and the creativity of employees. The study also revealed that the ability of relational leaders to drive knowledge-sharing behaviour was not contingent on leader–follower dyadic tenure.

Practical implications

The results of this study have practical relevance for human resource practitioners in the hospitality industry. Given that relational leadership has a positive relationship with employee creativity, the authors recommend that hotel supervisors relate well with employees by sharing valuable information and respecting their opinions in decision-making.

Originality/value

Studies on the role of relational leadership and employee creativity are scanty. This study develops a model to explain how relational leadership could influence employee creativity by incorporating knowledge-sharing behaviour and leader–follower dyadic tenure.
Mapping talent agility: a bibliometric analysis and future research agenda
Authors: Gouda Gopal Krushna , Tiwari Binita
Published: September 2022

Purpose

This study explores the concept of “talent agility” since its inception using bibliometric analysis and paves the way for future research agenda in the field of business and management.

Design/methodology/approach

The articles were retrieved from the Scopus database comprising 67 publications from 2001 to September 2020. This study has applied bibliometric techniques such as citation analysis, co-citation analysis, bibliographic coupling, co-authorship analysis, and co-occurrence keyword analysis.

Findings

The bibliometric analysis reveals the publication trends, most influential authors, articles, journals, countries, and important keywords. Subsequently, it presents the network connections among them in the field of talent agility. It identified emerging research diversifications in the literature on talent agility.

Research limitations/implications

The limitation of this study is the extraction of research articles from a single database, i.e. Scopus. This study provides insights to the researchers and practitioners on comprehensive understandings of the emerging concept “talent agility”, an overview of the publication trends, emerging research themes identified in the clusters, and suggests possible directions for further study.

Originality/value

This study provides the intellectual structure of talent agility literature and its advancement over the periods.
The relationship between vendor managed inventory and operational performance
Authors: Owusu Kwateng Kwame , Fokuoh Benjamin , Tetteh Francis Kamewor
Published: September 2022

Purpose

For the supply chain to be responsive in the age of globalization, the firm needs to adopt strategies to enable them to meet the changing market needs. Thus, it is essential to adopt automatic replenishment programmes such as vendor-managed inventory (VMI). This study sought to examine the relationship between VMI and operational performance (OP) and the moderation roles of leadership and digitization in the mining sector.

Design/methodology/approach

A quantitative approach was used, including primary data collected from industry players in the mining sector in Ghana. A total of 97 industry players were included in the study. Data gathered was analysed using SPSS and LISREL (8.5).

Findings

The results indicate that VMI significantly affects OP. However, both digitization and leadership failed to moderate the relationship between VMI and OP.

Practical implications

The study offers mining companies an understanding of VMI applications in their industry. The knowledge will stimulate and improve inventory management practices in the mining industry.

Originality/value

This study is among the first few attempts to understand VMI in the mining industry, especially in the Sub-Saharan Africa context. It presents a detailed understanding of VMI and opportunities for future research.
Food and food‐related waste management strategies in hospital food services: A systematic review
Authors: Cook Nathan , Goodwin Denise , Porter Judi , Collins Jorja
Published: September 2022

Aim

This review explored peer‐reviewed and grey literature to describe the types and characteristics of food or food‐related waste management strategies used in hospital food service settings; their financial, environmental and staffing outcomes; and the barriers and enablers associated with their implementation.

Methods

Six electronic databases, 17 Google Advanced searches, and 19 targeted websites were searched for peer‐reviewed and grey literature. Literature reporting the financial, environmental, or staffing outcomes of food or food‐related waste management strategies that reused, recovered energy from, or recycled waste instead of sending it to landfill were eligible. Document screening and review were completed in duplicate, and included peer‐reviewed literature were assessed for quality using the Mixed Methods Appraisal Tool. Data were synthesised narratively.

Results

Four peer‐reviewed and 81 grey literature records reported 85 strategies. When grouped from most to least favourable according to the food recovery hierarchy they managed waste by: donating surplus food (n = 21); feeding animals (n = 2); industrial use (n = 11); composting (n = 34) and other (n = 17). These approaches had the capacity to reduce waste hauling fees (n = 14), reduce staff handling of waste (n = 3), and decrease the amount of waste sent to landfill (n = 85). Barriers included contamination of waste streams, while enablers included leadership and time‐neutral changes.

Conclusion

This review summarises the waste management strategies used by hospitals worldwide that divert food and food‐related waste from landfill, their outcomes, and position in the food recovery hierarchy to enable hospital food services to implement appropriate practice and policy changes to decrease their environmental footprint.
Rheological properties of dairy desserts: Effect of rice bran protein and fat content
Authors: Mohammadi Atefeh , Shahidi Seyed‐Ahmad , Rafe Ali , Naghizadeh Raeisi Shahram , Ghorbani‐HasanSaraei Azade
Published: September 2022

Rice bran protein (RBP) is an alternative plant protein that can be used in a wide range of foods due to its unique functional, nutritional, and hypoallergenic properties. The interactions of RBP with other biopolymers have revealed its feasibility for application in dairy products such as whipped cream and dairy desserts. Therefore, the effects of RBP and fat content on the rheological properties of dairy desserts were investigated. The pH value was not influenced by protein, but the nonfat milk solid content was changed by fat and protein content. All the desserts showed thixotropic properties which were mainly related to the molecular disentanglement at high shear rates. By increasing fat like RBP, the apparent viscosity (ηa) was increased. Rheological parameters such as n value, thixotropic index, storage (G′), and loss moduli (G′′) were increased by RBP. Moreover, the dairy desserts containing RBP and whole milk presented generally higher G′, G′′, complex modulus, and complex viscosity values, and lower tan δ values. The RBP enriched samples also had a higher hardness and gumminess. Syneresis was decreased by RBP, which was related to the formation of ordered mesh‐like structures which enabled the entrapment of more water. There was a positive correlation between the rheological, textural, and physical properties of the dessert with added RBP, and therefore dairy dessert attributes can be improved along with fat reduction. However, a sensory evaluation is needed to unravel the acceptability rate of RBP in fat reduction from the view point of consumers.

Practical Application

Rice bran protein (RBP) has nutritional and hypoallergenic properties which enable it to apply to many products such as dairy desserts. One of the main concerns in dairy technology is the growing interest in low‐fat products due to health problems. RBP showed unique properties which makes the creamy behavior. The rheological results have elucidated the creaminess associated with RBP and can assist in the proper simulation of mouthfeel.
Polyhydroxyalkanoate production from animal by‐products: Development of a pneumatic feeding system for solid fat/protein‐emulsions
Authors: Gutschmann Björn , Högl Thomas H. , Huang Boyang , Maldonado Simões Matilde , Junne Stefan , Neubauer Peter , Grimm Thomas , Riedel Sebastian L.
Published: September 2022

Fat‐containing animal by‐product streams are locally available in large quantities. Depending on their quality, they can be inexpensive substrates for biotechnological processes. To accelerate industrial polyhydroxyalkanoate (PHA) bioplastic production, the development of efficient bioprocesses that are based on animal by‐product streams is a promising approach to reduce overall production costs. However, the solid nature of animal by‐product streams requires a tailor‐made process development. In this study, a fat/protein‐emulsion (FPE), which is a by‐product stream from industrial‐scale pharmaceutical heparin production and of which several hundred tons are available annually, was evaluated for PHA production with Ralstonia eutropha. The FPE was used as the sole source of carbon and nitrogen in shake flask and bioreactor cultivations. A tailored pneumatic feeding system was built for laboratory bioreactors to facilitate fed‐batch cultivations with the solid FPE. The process yielded up to 51 g L−1 cell dry weight containing 71 wt% PHA with a space–time yield of 0.6 gPHA L−1 h−1 without using any carbon or nitrogen sources other than FPE. The presented approach highlights the potential of animal by‐product stream valorization into PHA and contributes to a transition towards a circular bioeconomy.
Reflectance spectroscopy allows rapid, accurate and non‐destructive estimates of functional traits from pressed leaves
Authors: Kothari Shan , Beauchamp‐Rioux Rosalie , Laliberté Etienne , Cavender‐Bares Jeannine
Published: September 2022

More than ever, ecologists seek to employ herbarium collections to estimate plant functional traits from the past and across biomes. However, many trait measurements are destructive, which may preclude their use on valuable specimens. Researchers increasingly use reflectance spectroscopy to estimate traits from fresh or ground leaves, and to delimit or identify taxa. Here, we extend this body of work to non‐destructive measurements on pressed, intact leaves, like those in herbarium collections.

Using 618 samples from 68 species, we used partial least‐squares regression to build models linking pressed‐leaf reflectance spectra to a broad suite of traits, including leaf mass per area (LMA), leaf dry matter content (LDMC), equivalent water thickness, carbon fractions, pigments, and twelve elements. We compared these models to those trained on fresh‐ or ground‐leaf spectra of the same samples.

The traits our pressed‐leaf models could estimate best were LMA (R2 = 0.932; %RMSE = 6.56), C (R2 = 0.855; %RMSE = 9.03), and cellulose (R2 = 0.803; %RMSE = 12.2), followed by water‐related traits, certain nutrients (Ca, Mg, N, and P), other carbon fractions, and pigments (all R2 = 0.514–0.790; %RMSE = 12.8–19.6). Remaining elements were predicted poorly (R2 < 0.5, %RMSE > 20). For most chemical traits, pressed‐leaf models performed better than fresh‐leaf models, but worse than ground‐leaf models. Pressed‐leaf models were worse than fresh‐leaf models for estimating LMA and LDMC, but better than ground‐leaf models for LMA. Finally, in a subset of samples, we used partial least‐squares discriminant analysis to classify specimens among 10 species with near‐perfect accuracy (>97%) from pressed‐ and ground‐leaf spectra, and slightly lower accuracy (>93%) from fresh‐leaf spectra.

These results show that applying spectroscopy to pressed leaves is a promising way to estimate leaf functional traits and identify species without destructive analysis. Pressed‐leaf spectra might combine advantages of fresh and ground leaves: like fresh leaves, they retain some of the spectral expression of leaf structure; but like ground leaves, they circumvent the masking effect of water absorption. Our study has far‐reaching implications for capturing the wide range of functional and taxonomic information in the world’s preserved plant collections.
Implementing GitHub Actions continuous integration to reduce error rates in ecological data collection
Authors: Kim Albert Y. , Herrmann Valentine , Barreto Ross , Calkins Brianna , Gonzalez‐Akre Erika , Johnson Daniel J. , Jordan Jennifer A. , Magee Lukas , McGregor Ian R. , Montero Nicolle , Novak Karl , Rogers Teagan , Shue Jessica , Anderson‐Teixeira Kristina J.
Published: September 2022

Accurate field data are essential to understanding ecological systems and forecasting their responses to global change. Yet, data collection errors are common, and data analysis often lags far enough behind its collection that many errors can no longer be corrected, nor can anomalous observations be revisited. Needed is a system in which data quality assurance and control (QA/QC), along with the production of basic data summaries, can be automated immediately following data collection.

Here, we implement and test a system to satisfy these needs. For two annual tree mortality censuses and a dendrometer band survey at two forest research sites, we used GitHub Actions continuous integration (CI) to automate data QA/QC and run routine data wrangling scripts to produce cleaned datasets ready for analysis.

This system automation had numerous benefits, including (1) the production of near real‐time information on data collection status and errors requiring correction, resulting in final datasets free of detectable errors, (2) an apparent learning effect among field technicians, wherein original error rates in field data collection declined significantly following implementation of the system, and (3) an assurance of computational reproducibility—that is, robustness of the system to changes in code, data and software.

By implementing CI, researchers can ensure that datasets are free of any errors for which a test can be coded. The result is dramatically improved data quality, increased skill among field technicians, and reduced need for expert oversight. Furthermore, we view CI implementation as a first step towards a data collection and analysis pipeline that is also more responsive to rapidly changing ecological dynamics, making it better suited to study ecological systems in the current era of rapid environmental change.
Estimating arboreality and the effects of forest structure on tropical tree‐dwelling mesomammals using arboreal camera traps
Authors: Masseloux J. , Le Q. T. , Burr J. , Gerber B. D.
Published: September 2022

Tropical forests are the most species‐rich biomes in the world but suffer high rates of logging and conversion. Tropical tree‐dwelling (arboreal and semi‐arboreal) mesomammals reliant on old‐growth forest structures are especially vulnerable. The degree of behavioral arboreality of semi‐arboreal mammals can be related to forest structure and perceived terrestrial threats. Paired arboreal and terrestrial camera traps are a promising new method for estimating the arboreality of cryptic and nocturnal species. Our study aimed to (1) model the effects of forest structure and anthropogenic disturbance on the detection and occurrence of arboreal and semi‐arboreal mesomammals and (2) evaluate differences in occurrence and detection between paired arboreal and terrestrial camera trap sites for semi‐arboreal mammals while estimating the degree of arboreality. We set 20 terrestrial and arboreal camera trap pairs in eastern Cat Tien National Park (Nam Cat Tien), Vietnam, from June 2019 to September 2020. We evaluated the effects of forest structure and proximity to roads on nine arboreal mesomammal species using single‐season occupancy models. We used multi‐scale occupancy modeling to estimate the degree of arboreality for four semi‐arboreal mammals. All models were fit using hierarchical Bayesian modeling and compared using WAIC. We detected most arboreal and terrestrial mesomammal species currently known to inhabit Nam Cat Tien, including rare and cryptic species. Canopy connectivity and other mature forest characteristics were important for explaining the detection and occurrence of highly arboreal species, while the effect of a tree and focal limb characteristics on detection was species‐specific. All semi‐arboreal species had a greater probability of terrestrial station use than arboreal, suggesting a greater vulnerability to terrestrial threats, though the degree of arboreality varied by species. Using one sampling method underestimated occupancy for most semi‐arboreal species. Multi‐method sampling designs with multi‐scale occupancy modeling can improve estimates of species distribution and habitat use for guiding management and conservation decisions.
Cervical pessary and cerclage placement for preterm birth prevention and cervicovaginal microbiome changes
Authors: Vargas Mireia , Yañez Francisca , Elias Andrea , Bernabeu Andrea , Goya Maria , Xie Zixuan , Farrás Alba , Sánchez Olga , Soler Zaida , Blasquez Carlos , Valle Leonor , Olivella Anna , Muñoz Begoña , Brik Maia , Carreras Elena , Manichanh Chaysavanh
Published: September 2022

Introduction

Our objective was to compare the vaginal microbiome in low‐risk and high‐risk pregnant women and to explore a potential association between vaginal microbiome and preterm birth.

Material and methods

A pilot, consecutive, longitudinal, multicenter study was conducted in pregnant women at 18–22 weeks of gestation. Participants were assigned to one of three groups: control (normal cervix), pessary (cervical length ≤25 mm) and cerclage (cervical length ≤25 mm or history of preterm birth). Analysis and comparison of vaginal microbiota as a primary outcome was performed at inclusion and at 30 weeks of gestation, along with a follow‐up of pregnancy and perinatal outcomes. We assessed the vaginal microbiome of pregnant women presenting a short cervix with that of pregnant women having a normal cervix, and compared the vaginal microbiome of women with a short cervix before and after placement of a cervical pessary or a cervical cerclage.

Results

The microbiome of our control cohort was dominated by Lactobacillus crispatus and inners. Five community state types were identified and microbiome diversity did not change significantly over 10 weeks in controls. On the other hand, a short cervix was associated with a lower microbial load and higher microbial richness, and was not correlated with Lactobacillus relative abundance. After intervention, the cerclage group (n = 19) had a significant increase in microbial richness and a shift towards community state types driven by various bacterial species, including Lactobacillus mulieris, unidentified Bifidobacterium or Enterococcus. These changes were not significantly observed in the pessary (n = 26) and control (n = 35) groups. The cerclage group had more threatened preterm labor episodes and poorer outcomes than the control and pessary groups.

Conclusions

These findings indicate that a short cervix is associated with an altered vaginal microbiome community structure. The use of a cerclage for preterm birth prevention, as compared with a pessary, was associated with a microbial community harboring a relatively low abundance of Lactobacillus, with more threatened preterm labor episodes, and with poorer clinical outcomes.
Relation between perinatal outcome and gestational duration in term primiparous pregnancies stratified by body mass index
Authors: Lindegren Lina , Stuart Andrea , Herbst Andreas , Källén Karin
Published: September 2022

Introduction

There is growing evidence that induction of labor at 41 completed weeks improves neonatal outcome, at least among primiparous women. This study was performed to investigate whether maternal body mass index (BMI) should be considered when deciding on timing of intervention in term pregnancies.

Material and methods

The study design was a historical cohort study using data from the Swedish Medical Birth Register, singletons in cephalic presentation with births 39+0 to 41+6 weeks, with available information on maternal BMI 2005–2017 (n = 352 567). Modified Poisson regression analyses were used to investigate the association between gestational duration and stillbirth or death before 45 postmenstrual weeks (primary outcome) and Apgar score <7 at 5 minutes (secondary outcome) by BMI, respectively. Adjustments were made for maternal age, smoking, country of birth and educational level.

Results

The adjusted relative risk (ARR) of stillbirth or death before 45 weeks among infants born at 41+0 to 41+6 vs 40+0 to 40+6 weeks, was 1.26 with a 95% confidence interval (CI) of 1.07–1.48. Among women with BMI ≥30, the offspring mortality risk in pregnancies lasting 39+0 to 39+2 weeks was significantly above the corresponding risk among women of normal BMI who delivered at 41+0 to 41+2 weeks (ARR = 1.95; 95% CI 1.07–3.56) but no statistically significant heterogeneity was found regarding the magnitude of the association between gestational duration and offspring mortality. The ARR, for Apgar <7 at 5 minutes (41+0 to 41+6 vs 40+0 to 40+6 weeks, regardless of BMI), was 1.36 (95% CI 1.27–1.45). The risk for low Apgar score at 41+0 weeks was 1.5% among all children regardless of maternal BMI. Among children to women with BMI ≥30, this magnitude of risk was found already at 39+3 weeks.

Conclusions

In primiparous women with obesity the risk of stillbirth or death before 45 postmenstrual weeks were increased throughout all full‐term gestational age categories, compared with women with overweight or normal BMI. Children to obese women had the same risk for Apgar scores <7 at 5 minutes compared with women overall at earlier gestational age. The results suggest that maternal BMI needs to be considered when discussing timing of elective induction in term healthy pregnancies of primiparous women.
Cutaneous endosalpingiosis arising from C‐section scar: A case report with review of literature
Authors: Shapiro Sarah , Abdulhak Abraham , Lenczowski Joi , Sayeed Sadia , Mochel Mark
Published: September 2022

Endosalpingiosis is a pathologic phenomenon in which non‐neoplastic fallopian tube epithelium implants in ectopic locations. It is an uncommon and poorly understood condition, with most cases occurring within the abdominopelvic cavity. Cutaneous presentations of endosalpingiosis are even more rare, with only six cases described in international literature to‐date. This report describes an additional case of cutaneous endosalpingiosis. The lesion arose within the scar tissue of a Pfannenstiel incision from 4 years prior in a 24‐year old, previously healthy African American female. Punch biopsy of the lesion revealed a cystic mass lined by PAX8+ciliated columnar cells and a surrounding fibrotic stroma with focal CD10‐positivity, consistent with a histopathologic diagnosis of endosalpingiosis. In addition, this report provides a comprehensive review of the other documented cases of cutaneous endosalpingiosis, as well as the proposed pathogenesis, histopathologic and clinical features, and potential treatment avenues for this unique clinical entity.
Human disturbances affect the topology of food webs
Authors: Mestre Frederico , Rozenfeld Alejandro , Araújo Miguel B.
Published: September 2022

Networks describe nodes connected by links, with numbers of links per node, the degree, forming a range of distributions including random and scale‐free. How network topologies emerge in natural systems still puzzles scientists. Based on previous theoretical simulations, we predict that scale‐free food webs are favourably selected by random disturbances while random food webs are selected by targeted disturbances. We assume that lower human pressures are more likely associated with random disturbances, whereas higher pressures are associated with targeted ones. We examine these predictions using 351 empirical food webs, generally confirming our predictions. Should the topology of food webs respond to changes in the magnitude of disturbances in a predictable fashion, consistently across ecosystems and scales of organisation, it would provide a baseline expectation to understand and predict the consequences of human pressures on ecosystem dynamics.
Mutation‐specific metabolic profiles in presymptomatic amyotrophic lateral sclerosis
Authors: Xia Kailin , Witzel Simon , Witzel Christina , Klose Veronika , Fan Dongsheng , Ludolph Albert C. , Dorst Johannes
Published: September 2022

Background and purpose

Growing evidence shows that ALS patients feature a disturbed energy metabolism. However, these features have rarely been investigated in the presymptomatic stage.

Methods

A total of 60 presymptomatic ALS mutation carriers and 70 age‐ and gender‐matched controls (non‐mutation carriers from the same families) were recruited. All subjects underwent assessments of their metabolic profiles under fasting conditions at enrollment, including body mass index (BMI), blood pressure and serum levels of blood glucose, total cholesterol, triglycerides, high‐density lipoprotein (HDL) and low‐density lipoprotein.

Results

All mutations combined, no differences between presymptomatic ALS gene carriers and controls were found. From a cardiovascular point of view, presymptomatic chromosome 9 open reading frame 72 (C9ORF72) gene carriers showed lower cardiovascular risk profiles compared to healthy controls, including lower BMI (median 22.9, interquartile range [IQR] 20.6–26.1 kg/m2 vs. 24.9, IQR 22.7–30.5 kg/m2; p = 0.007), lower systolic blood pressure (120, IQR 110–130 mmHg vs. 128, IQR 120–140 mmHg; p = 0.02), lower fasting serum glucose (89.0, IQR 85.0–97.0 mg/dl vs. 96.0, IQR 89.3–102.0 mg/dl; p = 0.005) and higher HDL (1.6, IQR 1.3–1.8 mmol/l vs. 1.2, IQR 1.0–1.4 mmol/l; p = 0.04). However, presymptomatic superoxide dismutase 1 (SOD1) gene mutation carriers showed higher cardiovascular risk profiles compared to healthy controls, including higher BMI (28.0, IQR 26.1–31.5 kg/m2 vs. 24.9, IQR 22.7–30.5 kg/m2; p = 0.02), higher fasting serum glucose (100.0, IQR 94.0–117.0 mg/dl vs. 96.0, IQR 89.3–102.0 mg/dl; p = 0.04) and lower HDL (1.2, IQR 1.0–1.4 mmol/l vs. 1.4, IQR 1.2–1.7 mmol/l; p = 0.01). These features were most prominent in patients carrying SOD1 gene mutations associated with slow disease progression.

Conclusions

This study identified distinct metabolic profiles in presymptomatic ALS gene carriers, which might be associated with disease progression in the symptomatic phase.