bluuebunny/crossref_metadata_2025_split huggingface dataset:
How might a collapse in the Atlantic Meridional Overturning Circulation affect rainfall over tropical South America?
Authors: Good Peter , Boers Niklas , Boulton Chris A. , Lowe Jason A. , Richter Ingo 
Published: December 2021

AbstractThe seasonal response of rainfall over tropical South America to a shutdown in the Atlantic Meridional Overturning Circulation (AMOC) is examined, in HadGEM3 model simulations where freshwater is added to the north Atlantic. Potential biases in these simulations are explored by comparing the unperturbed simulation with observations. In this simulation, in years when the latitude of the model Atlantic Intertropical Convergence Zone (ITCZ) is realistic, the model provides a reasonable simulation of the spatial and seasonal variation in regional‐scale rainfall over tropical South America. However, some climatological mean rainfall biases over this region are attributed to the climatological southward bias in the Atlantic ITCZ. Under an AMOC shutdown, the rainfall changes over tropical South America are largely associated with a southward shift of the Atlantic ITCZ. The large seasonal variation in rainfall change over tropical South America is linked primarily with the variation in the location of peak rainfall (itself driven largely by variation in the latitude of peak solar insolation and by the lagged variation in Atlantic ITCZ). The simulated rainfall changes appear to be biased in some months by the southward bias in the Atlantic ITCZ, including a possible overestimation of drying in March and June. In addition, the Atlantic ITCZ in HadGEM3 tends to shift too far in both the seasonal cycle (as reported in other models) and in inter‐annual variability. Excessive inter‐annual variability may arise because the model ITCZ is too close to the equator, combined with an increase in variability near the equator. Further understanding of what drives the variability in ITCZ latitude, and how that relates to ITCZ shifts under an AMOC shutdown, is suggested as a future research priority.
Amino‐Acid‐Anthraquinone Click Chemistry Conjugates Selectively Target Human Telomeric G‐Quadruplexes
Authors: Ongaro Alberto , Desiderati Giovanni , Oselladore Erika , Auricchio Davide , Memo Maurizio , Ribaudo Giovanni , Sissi Claudia , Gianoncelli Alessandra 
Published: December 2021

AbstractGuanine‐rich sequences are known to fold into G‐quadruplex (G4) arrangements, which are present in oncogenes and in the telomeric regions of chromosomes. In particular, G4s represent an obstacle to functioning of telomerase, an enzyme overexpressed in cancer cells causing their immortalization. Therefore, G4 stabilization using small molecules represents an appealing strategy for the medicinal chemist. Ligands based on an anthraquinone scaffold, to which peptidic side chains were attached by an amide bond, were previously reported. We envisioned improving this ligand concept leveraging the click chemistry approach, which, besides representing a flexible, high yielding synthetic strategy, allows an elongation of the side chains and an increase of π–π stacking and H‐bond interactions with the nucleobases through the triazole ring. Compounds were tested for their ability to interact with G4 DNA with a multiple analytical approach, demonstrating an elevated aptitude to stabilize the G4 and high selectivity over double stranded DNA.
DeepCM: Deep neural networks to improve accuracy prediction of database cost models
Authors: Ouared Abdelkader , Chadli Abdelhafid , Daoud Mohamed Amine 
Published: December 2021

AbstractA major challenge for many database management tasks including admission control, query scheduling, progress monitoring and self‐driving data storage systems is to enhance queries performances which are based on computational models known as database cost models. One of the most challenging aspects of developing accurate database cost models is identifying their parameters and capturing their relationships, consequently we can derive the query execution cost on the basis of a specific database hosted on a given platform. Furthermore, the highly dynamic workload (i.e., a set of queries) and the query execution variation lead to performance degradation risk, therefore cost models need to be improved by considering newer software configuration and future workload characteristics. In this article, we propose a framework called DeepCM that is based on a min–max optimization for building robust database cost model against uncertainty parameters. Furthermore, our framework is based on Robust Deep Neural Networks to build database cost models that guarantee a high accuracy regardless of variations from software configuration and workload characteristics. Several experiments have been done to evaluate the robustness of produced cost models and findings show that DeepCM provides a high cost model prediction accuracy and stable performance.
The Vulnerability Index: A weighted measure of dementia and cognitive impairment risk
Authors: Kleiman Michael J. , Galvin James E. 
Published: December 2021

AbstractIntroductionA brief, easily calculated and interpretable index to assess vulnerability to developing cognitive impairment is needed in clinical practice and research. To address this, we developed the Vulnerability Index (VI) with the goal of identifying individuals possessing a high risk for cognitive impairment.MethodsTwelve easily obtained sociodemographic, medical, and functional factors were used to develop the VI, with each selectively weighted based on factor analysis and predictive modeling. This cross‐sectional study examined 387 subject‐partner dyads.ResultsThe VI was found to accurately discriminate between cognitively normal controls and participants with cognitive impairment (area under the curve [AUC]: 0.844; 95% confidence interval [CI]: 0.776‐0.913) and individuals scoring high on the VI (≥8) had worse health, functional, behavioral, cognitive, and quality of life ratings than those with lower scores.DiscussionThe VI could be used in screening asymptomatic individuals for risk of cognitive impairment and guiding the development of primary and secondary prevention plans.
Smoothing splines of apex predator movement: Functional modeling strategies for exploring animal behavior and social interactions
Authors: Whetten Andrew B. 
Published: December 2021

AbstractThe collection of animal position data via GPS tracking devices has increased in quality and usage in recent years. Animal position and movement, although measured discretely, follows the same principles of kinematic motion, and as such, the process is inherently continuous and differentiable. I demonstrate the functionality and visual elegance of smoothing spline models. I discuss the challenges and benefits of implementing such an approach, and I provide an analysis of movement and social interaction of seven jaguars inhabiting the Taiamã Ecological Station, Pantanal, Brazil, a region with the highest known density of jaguars. In the analysis, I derive measures for pairwise distance, cooccurrence, and spatiotemporal association between jaguars, borrowing ideas from density estimation and information theory. These measures are feasible as a result of spline model estimation, and they provide a critical tool for a deeper investigation of cooccurrence duration, frequency, and localized spatio‐temporal relationships between animals. In this work, I characterize a variety of interactive relationships between pairs of jaguars, and I particularly emphasize the relationships in movement of two male–female and two male–male jaguar pairs exhibiting highly associative relationships.
How do Snow Partridge (Lerwa lerwa) and Tibetan Snowcock (Tetraogallus tibetanus) coexist in sympatry under high‐elevation conditions on the Qinghai–Tibetan Plateau?
Authors: Yao Hongyan , Wang Pengcheng , Davison Geoffrey , Wang Yong , McGowan Philip J. K. , Wang Nan , Xu Jiliang 
Published: December 2021

AbstractThe Qinghai–Tibetan Plateau (QTP) has the highest elevations of all biodiversity hotspots. Difficulties involved in fieldwork at high elevations cause challenges in researching mechanisms facilitating species coexistence. Herein, we investigated Snow Partridge (Lerwa lerwa) and Tibetan Snowcock (Tetraogallus tibetanus), the only two endemic Galliformes on the QTP, to understand species coexistence patterns and determine how they live in sympatry for the first time. We assembled occurrence data, estimated habitat suitability differences and the underlying factors between two species at different scales using ecological niche models. Niche overlap tests were used to investigate whether niche differences between these species allow for their coexistence. We found that elevation was the most important factor determining habitat suitability for both species. At the meso‐scale, two species have similar ecological niches with their suitable habitats lying predominantly along ridge crests. However, ridge crests were more influential for habitat suitability by L. lerwa than for that of T. tibetanus because the latter species ranges further afield than ridge crests. Thus, differences in habitat suitability between these species lead to habitat partitioning, which allows stable coexistence. At the macro‐scale, temperature and precipitation were major factors influencing habitat suitability differences between these species. Tetraogallus tibetanus extended into the hinterland of the QTP and occurred at higher elevations, where colder and drier alpine conditions are commonplace. Conversely, L. lerwa occurred along the southeastern margin of the QTP with a lower snow line, an area prone to rainy and humid habitats. Niche overlap analysis showed that habitat suitability differences between these species are not driven by niche differentiation. We concluded that the coexistence of these two pheasants under high‐elevation conditions could be an adaption to different alpine conditions.
Twenty‐five years of tree demography in a frequently burned oak woodland: implications for savanna restoration
Authors: Davis Mark A. 
Published: December 2021

AbstractDue to decades of fire suppression, much of the Upper Midwest savanna habitat has converted to oak woodland. In efforts to restore oak savanna habitat, fire has been re‐introduced in many of these woodlands. A primary purpose of these burns is to kill the fire‐sensitive mesophytic tree species, which had established themselves during the decades of fire suppression, reduce the number of understory trees, and preserve the larger more widely spaced oaks. It is clear from ongoing efforts that restoring oak savannas will require frequent fires over decades, but frequent fires over the long term can also threaten the desirable oaks. Long‐term demographic studies at savanna restoration sites experiencing frequent fires are necessary to determine the extent to the frequent burns are supporting and/or confounding restoration goals. Results presented here are from a twenty‐five‐year demographic study of an Upper Midwest bur oak (Quercus macrocarpa) savanna/woodland experiencing frequent fire, during which both the survival and growth of more than 9000 trees were documented. Survival was assessed annually and growth every five years. In the face of frequent fires, stem survival was found to be strongly associated with tree species, stem size, and stem growth. In turn, stem growth was found to be related to tree species and stem size. Decades of frequent burning in this oak woodland have substantially reduced the abundance of unwanted trees, specifically mesophytic species and Quercus ellipsoidalis, the latter which outcompetes Q. macrocarpa in the absence of fire. While Q. macrocarpa mid‐sized (10–25 cm dbh) and large (≥25 cm dbh) trees are quite resistant to fire and now dominate the savanna landscape, they are not immune from fire‐induced mortality. It is recommended that the number and density of these trees should be re‐evaluated every few years to ensure that desirable numbers remain. If necessary, fires should be suspended for a period of time. This will give smaller Q. macrocarpa trees time to grow larger and become more fire‐resistant, thereby ensuring successive generations of Q. macrocarpa.
Pond ecology and conservation: research priorities and knowledge gaps
Authors: Hill Matthew J. , Greaves Helen M. , Sayer Carl D. , Hassall Christopher , Milin Mélanie , Milner Victoria S. , Marazzi Luca , Hall Ruth , Harper Lynsey R. , Thornhill Ian , Walton Richard , Biggs Jeremy , Ewald Naomi , Law Alan , Willby Nigel , White James C. , Briers Robert A. , Mathers Kate L. , Jeffries Michael J. , Wood Paul J. 
Published: December 2021

AbstractPonds are among the most biodiverse and ecologically important freshwater habitats globally and may provide a significant opportunity to mitigate anthropogenic pressures and reverse the decline of aquatic biodiversity. Ponds also provide important contributions to society through the provision of ecosystem services. Despite the ecological and societal importance of ponds, freshwater research, policy, and conservation have historically focused on larger water bodies, with significant gaps remaining in our understanding and conservation of pond ecosystems. In May 2019, pond researchers and practitioners participated in a workshop to tackle several pond ecology, conservation, and management issues. Nine research themes and 30 research questions were identified during and following the workshop to address knowledge gaps around: (1) pond habitat definition; (2) global and long‐term data availability; (3) anthropogenic stressors; (4) aquatic–terrestrial interactions; (5) succession and disturbance; (6) freshwater connectivity; (7) pond monitoring and technological advances; (8) socio‐economic factors; and (9) conservation, management, and policy. Key areas for the future inclusion of ponds in environmental and conservation policy were also discussed. Addressing gaps in our fundamental understanding of pond ecosystems will facilitate more effective research‐led conservation and management of pondscapes, their inclusion in environmental policy, support the sustainability of ecosystem services, and help address many of the global threats driving the decline in freshwater biodiversity.
Climate change impacts on ecosystems and adaptation options in nine countries in southern Africa: What do we know?
Authors: Kapuka Alpo , Hlásny Tomáš 
Published: December 2021

AbstractSouthern Africa harbors exceptional biodiversity that is increasingly threatened by climate change, land use, and other pressures. However, risks to the regional ecosystems and quality and consistency of adaptation strategies remain understudied, making conservation and restoration efforts challenging. Here, we reviewed scientific articles published during the period 2000–2020, which (1) addressed observed and projected impacts of climate change on different species, populations, and ecosystems in nine southern African countries, and (2) formulated management and policy responses aiming to mitigate these impacts. We identified and evaluated 28 papers meeting these search criteria. We found that the three components of our investigation, that is, ecosystem type, type of impact, and management and policy responses, were covered by research rather fragmentarily. However, the reviewed publications addressed a large variety of species and ecosystems and a variety of processes, from local extinction, range contraction, and increased mortality to modified inter‐specific interactions. The identified human responses included active vegetation and animal management, improved conservation policies, and monitoring. Most of the publications highlighted severe data limitations, lacking coordination of conservation policies, and insufficient consideration of transient environmental conditions in management and policy planning. We conclude that the current level of understanding of climatic threats to species and ecosystems is limited in southern Africa, and new coordinated research and monitoring actions are needed. This review characterized the high diversity of climate change risks to ecosystems and related social responses, potentially helping to attract further research attention and inform regional adaptation strategies.
Discordance between estimated and measured changes in plasma volume among patients with acute heart failure
Authors: Swolinsky Jutta S. , Tuvshinbat Enkhtuvshin , Leistner David M. , Edelmann Frank , Knebel Fabian , Nerger Niklas P. , Lemke Caroline , Roehle Robert , Haase Michael , Costanzo Maria Rosa , Rauch Geraldine , Mitrovic Veselin , Gasanin Edis , Meier Daniel , McCullough Peter A. , Eckardt Kai‐Uwe , Molitoris Bruce A. , Schmidt‐Ott Kai M. 
Published: December 2021

AbstractAimsIn acute heart failure (AHF), changes of venous haemoglobin (Hb) concentrations, haematocrit (Hct), and estimated plasma volume (ePV) have been proposed as surrogates of decongestion. These estimates are based on the theoretical assumptions that changes of Hb concentrations and Hct are driven by the intravascular volume status and that the intravascular Hb pool remains stable. The objective of this study was to assess the relationship of changes of measured plasma volume (mPV) with changes of Hb, Hct, and ePV in AHF.Methods and resultsWe studied 36 AHF patients, who received two sequential assessments of mPV, measured red cell volume (mRCV) and measured total blood volume (mTBV) (48 h apart), during the course of diuretic therapy using a novel visible fluorescent injectate (VFI) technique based on the indicator dilution principle. Changes of ePV were calculated based on the Kaplan–Hakim or Strauss formula. AHF patients receiving diuretics (median intravenous furosemide equivalent 160 mg/48 h) displayed a wide range of changes of mPV (−25.4% to +37.0%). Changes in mPV were not significantly correlated with changes of Hb concentration [Pearson's r (r) = −0.241, P = 0.157], Hct (r = −0.307, P = 0.069), ePVKaplan–Hakim (r = 0.228, P = 0.182), or ePVStrauss (r = 0.237, P = 0.163). In contrast to theoretical assumptions, changes of mTBV were poorly correlated with changes of Hb concentrations and some patients displayed unanticipated variability of mRCV, suggesting an unstable intravascular red cell pool.ConclusionsChanges of Hb or Hct were not reflective of directly measured changes of intravascular volume status in AHF patients. Basing clinical assessment of decongestion on changes of Hb or Hct may misguide clinical decision‐making on an individual patient level.
Optimization of Square Wave Voltammetry (SWV) Parameters by Design of Experiment (DoE) Methodologies for the Determination of Mifepristone at Glassy Carbon Electrode (GCE)
Authors: Makwakwa Tlou A. , Mafa Potlako J. , Nyoni Hlengilizwe , Msagati Titus A. M. 
Published: December 2021

AbstractIn the present study, an electroanalytical method that permits the optimization of factors affecting SWV for sensitive detection of mifepristone at glassy carbon electrode (GCE) using response surface methodology (RSM) with desirability function (DF) is presented. Factors selected for optimization after screening using full factorial design were frequency (X1), amplitude (X2), and pH (X3). The central composite design as a response surface methodology with desirability function (DF) was applied for obtaining the optimum level. The optimum conditions were obtained as follows: Frequency (X1=50 Hz), amplitude (X2=33.4 mV), and pH (X3=9.4), with an overall desirability function of 0.97. Subsequently, confirmatory experiments were performed in triplicates to validate the optimum conditions. The results obtained were satisfactory and agreed well with less only 11.9 % deviation from the values predicted by the model. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.54 and 1.80 ppm, respectively. The proposed method was applied for a quantitative determination of mifepristone in spiked tap water samples. The recovery tests showed that the detection of mifepristone at GC could be evaluated on environmental samples.
An electrochemical comparison of thiolated self‐assembled monolayer (SAM) formation and stability in solution on macro‐ and nanoelectrodes
Authors: Piper Andrew , Corrigan Damion K. , Mount Andrew R. 
Published: December 2021

AbstractThiolated self‐assembled monolayers (SAMs) formed on metal electrodes have been a topic of interest for many decades. One of the most common applications is in the field of biosensors, where this is a growing need for functionalizing nanoelectrodes to realize more sensitive and implantable sensors. For all these applications, the SAM‐functionalized nanoelectrodes will need to make reliable and interpretable electrochemical measurements. In this work, electrochemical impedance spectroscopy (EIS) is used to monitor both the formation and subsequent stability of 6‐mercaptohexan‐1‐ol SAMs on macro and nanoelectrodes and compares the two. To develop effective devices, it is crucial to understand both SAM formation and the resulting signal stability on nanoscale surfaces and this is done by comparing to behaviors observed at the well‐understood macroscale. We report an initial stochastic binding event and subsequent re‐arrangement of the SAMs for both electrode types. However, this re‐arrangement takes hours on the macroscale electrodes but only seconds on the nanoelectrodes. This is proposed to be due to the different structures of the SAMs on the electrodes predominantly driven by their bulk‐to‐edge ratios. After formation, the SAMs formed on both macro‐ and nanoelectrodes exhibit significant instability over time. The reported results have practical implications for the construction of SAM‐based biosensors on macro‐ and nanoscale electrodes.
Impact of dopant ratio on the energy harvesting activity of polyaniline modified counter electrodes for Pt‐free dye‐sensitized solar cells
Authors: Farooq Shehna , Bilal Salma , Tahir Asif Ali , Shah Anwar ul Haq Ali 
Published: December 2021

AbstractCounter electrode (CE) is an essential part of dye‐sensitized solar cells (DSSCs) in determining their efficiency. Ultimately, the high catalytic activity and conductivity of a CE are dependent on the type of electrode material. The utilization of polyaniline (PANI) coatings for surface modification of CE has proven to be worth. Though it is a bit difficult to optimize the efficiency of a polymeric material, a proper combination of inorganic‐organic dopants can impart positive synergistic effects to the resulting PANI in terms of good conductivity, electrocatalytic activity, and low resistance. This work reports on the effect of the combination ration of an organic dopant (ammonium lauryl sulfate, ALS) and an inorganic dopant (sulfuric acid) on the catalytic activity of CEs modified with PANI for DSSCs. The results are compared with those of platinum counter electrode (Pt CE). The maximum conversion efficiency of DSSC with optimized case reaches 4.54%, which is higher than that of Pt counter electrode (4.02%). This organic–inorganic acids doped polymeric material showing an enhanced photoelectrochemical activity might be exploited in the future as a promising material for application in next‐generation solar devices.