bluuebunny/crossref_metadata_2025_split huggingface dataset:
The potential for cleaner fish‐driven evolution in the salmon louse Lepeophtheirus salmonis: Genetic or environmental control of pigmentation?
Authors: Hamre Lars Are , Oldham Tina , Oppedal Frode , Nilsen Frank , Glover Kevin Alan 
Published: May 2021

AbstractThe parasitic salmon louse represents one of the biggest challenges to environmentally sustainable salmonid aquaculture across the globe. This species also displays a high evolutionary potential, as demonstrated by its rapid development of resistance to delousing chemicals. In response, farms now use a range of non‐chemical delousing methods, including cleaner fish that eat lice from salmon. Anecdotal reports suggest that in regions where cleaner fish are extensively used on farms, lice have begun to appear less pigmented and therefore putatively less visible to cleaner fish. However, it remains an open question whether these observations reflect a plastic (environmental) or adaptive (genetic) response. To investigate this, we developed a pigment scoring system and conducted complimentary experiments which collectively demonstrate that, a) louse pigmentation is strongly influenced by environmental conditions, most likely light, and b) the presence of modest but significant differences in pigmentation between two strains of lice reared under identical conditions. Based on these data, we conclude that pigmentation in the salmon louse is strongly influenced by environmental conditions, yet there are also indications of underlying genetic control. Therefore, lice could display both plastic and adaptive responses to extensive cleaner fish usage where visual appearance is likely to influence survival of lice.
Recording fine‐scale movement of ground beetles by two methods: Potentials and methodological pitfalls
Authors: Růžičková Jana , Elek Zoltán 
Published: May 2021

AbstractMovement trajectories are usually recorded as a sequence of discrete movement events described by two parameters: step length (distance) and turning angle (bearing). One of the most widespread methods to record the geocoordinates of each step is by a GPS device. Such devices have limited suitability for recording fine movements of species with low dispersal ability including flightless carabid beetles at small spatio‐temporal scales. As an alternative, the distance‐bearing approach can avoid the measurement error of GPS units since it uses directly measured distances and compass azimuths. As no quantification of measurement error between distance‐bearing and GPS approaches exists so far, we generated artificial fine‐scale trajectories and in addition radio‐tracked living carabids in a temperate forest and recorded each movement step by both methods. Trajectories obtained from distance‐bearing were compared to those obtained by a GPS device in terms of movement parameters. Consequently, both types of trajectories were segmented by state‐switching modeling into two distinct movement stages typical for carabids: random walk and directed movement. We found that the measurement error of GPS compared to distance‐bearing was 1.878 m (SEM = 0.181 m) for distances and 31.330° (SEM = 2.066°) for bearings. Moreover, these errors increased under dense forest canopy and rainy weather. Distance error did not change with increasing distance recorded by distance‐bearing but bearings were significantly more sensitive to error at short distances. State‐switching models showed only slight, not significant, differences in movement states between the two methods in favor of the random walk in the distance‐bearing approach. However, the shape of the GPS‐measured trajectories considerably differed from those recorded by distance‐bearing caused especially by bearing error at short distances. Our study showed that distance‐bearing could be more appropriate for recording movement steps not only of ground‐dwelling beetles but also other small animals at fine spatio‐temporal scales.
Connectivity: insights from the U.S. Long Term Ecological Research Network
Authors: Iwaniec David M. , Gooseff Michael , Suding Katharine N. , Samuel Johnson David , Reed Daniel C. , Peters Debra P. C. , Adams Byron , Barrett John E. , Bestelmeyer Brandon T. , Castorani Max C. N. , Cook Elizabeth M. , Davidson Melissa J. , Groffman Peter M. , Hanan Niall P. , Huenneke Laura F. , Johnson Pieter T. J. , McKnight Diane M. , Miller Robert J. , Okin Gregory S. , Preston Daniel L. , Rassweiler Andrew , Ray Chris , Sala Osvaldo E. , Schooley Robert L. , Seastedt Timothy , Spasojevic Marko J. , Vivoni Enrique R. 
Published: May 2021

AbstractEcosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation‐funded Long‐Term Ecological Research (LTER) network addressing the core research area of “populations and communities.” The objective of this effort was to show the importance of long‐term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case study about what their site could look like in 50–100 yr as human and environmental drivers influencing specific ecosystems change. As the case studies were prepared, five themes emerged, and the studies were grouped into papers in this LTER Futures Special Feature addressing state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the “connectivity” theme and has examples from the Phoenix (urban), Niwot Ridge (alpine tundra), McMurdo Dry Valleys (polar desert), Plum Island (coastal), Santa Barbara Coastal (coastal), and Jornada (arid grassland and shrubland) sites. Connectivity has multiple dimensions, ranging from multi‐scalar interactions in space to complex interactions over time that govern the transport of materials and the distribution and movement of organisms. The case studies presented here range widely, showing how land‐use legacies interact with climate to alter the structure and function of arid ecosystems and flows of resources and organisms in Antarctic polar desert, alpine, urban, and coastal marine ecosystems. Long‐term ecological research demonstrates that connectivity can, in some circumstances, sustain valuable ecosystem functions, such as the persistence of foundation species and their associated biodiversity or, it can be an agent of state change, as when it increases wind and water erosion. Increased connectivity due to warming can also lead to species range expansions or contractions and the introduction of undesirable species. Continued long‐term studies are essential for addressing the complexities of connectivity. The diversity of ecosystems within the LTER network is a strong platform for these studies.
Rice paddy irrigation seasonally impacts stream benthic macroinvertebrate diversity at the catchment level
Authors: Ko Chia‐Ying , Asano Satoshi , Lin Meng‐Ju , Ikeya Tohru , Peralta Elfritzson M. , Triño Ellis Mika C. , Uehara Yoshitoshi , Ishida Takuya , Iwata Tomoya , Tayasu Ichiro , Okuda Noboru 
Published: May 2021

AbstractAgriculture is one of the most critical anthropogenic disturbances to freshwater ecosystems globally. In monsoon Asia, rice paddies provide habitats for aquatic species, but how their associated irrigation systems can affect downstream ecosystems is poorly understood. Here, we used structural equation modeling (SEM) to estimate seasonal variations in benthic macroinvertebrate diversity and environments and quantified indirect effects of land use, especially of rice paddy areas, on benthic macroinvertebrate diversity through local environmental alteration. Our study site was the Yasu River tributary of Lake Biwa, Japan, and we performed our investigation during both irrigation and nonirrigation periods, representing different seasons. Seasonal variations in physical and chemical variables and diversity were observed. Seasonal particulate phosphorus concentrations to a large extent determined the abundance and community composition of benthic macroinvertebrates. SEM revealed that the proportions of forest, urban, and rice paddy areas in the catchment had significant indirect effects on biodiversity indices of local benthic macroinvertebrate communities. The proportion of forest area had robust negative effects on water temperature, but the overall indirect effects on the macroinvertebrate diversity contrasted between the two seasonal periods. The proportion of rice paddy area had a strongly negative indirect effect on the diversity through increased particulate phosphorous loading during the irrigation period, while the proportion of urban area had a significantly negative indirect effect during the nonirrigation period only. The seasonal negative impacts of rice paddy irrigation on benthic macroinvertebrate communities were possibly due to siltation arising from rice paddy soils. Our results have implications for environmental restoration and biodiversity conservation in catchment management.
Borealization and its discontents: drivers of regional variation in plant diversity across scales in interior Alaska
Authors: Roland Carl , Schmidt Joshua H. , Stehn Sarah E. , Hampton‐Miller Celia J. , Nicklen E. Fleur 
Published: May 2021

AbstractQuantitative studies of regional variation in plant diversity across eastern Beringia (northern Alaska and adjacent areas) are lacking due to an absence of datasets of sufficient scale and scope. We interrogated a landscape‐scale plant diversity dataset collected across two regions of interior Alaska with different disturbance, topographic, and climate attributes to investigate hypotheses regarding drivers of plant species richness. Our approach integrated a multi‐scale sampling design with an analytical framework focused on quantifying how components of plant diversity (growth forms, biogeographic groups, and dominant species) respond to site factors that vary along landscape gradients. Our results revealed essential similarities in both the composition of the overall floras and the influences on local and meso‐scale species richness across both regions. However, these continuities at smaller scales contrasted with differences in landscape‐level distribution of plant diversity patterns along elevation gradients. Our findings suggest that local drivers of richness and occupancy interacted with differing macro‐scale attributes (e.g., relative continentality) to produce distinctive landscape‐level diversity patterns. Our results confirm that high levels of local and meso‐scale plant richness in interior Alaska depend on conditions that foster richness of herbaceous and northerly distributed species groups. However, we found that important differences in landscape‐level richness patterns were driven by regional differences in climate, topoedaphic variables, and disturbance. In the warmer region, woody species and boreal plant communities extended to higher elevations and common species occupancy showed marginally greater influence of fire. Overall richness was relatively low in alpine areas of the warmer region but heterogeneous edaphic and topographic circumstances stimulated higher species turnover in lower elevations there, increasing landscape‐level richness. In contrast, in the cooler region, woody species showed restricted distribution across the elevation gradient while site attributes associated with increased species richness aligned with the elevation gradient and thus peak richness occurred in the alpine zone. Our results show how total and growth‐form richness, as well as community composition, vary regionally in relation to important drivers (including growing season warmth) across interior Alaska. Consequently, our study provides new insights into the potential trajectories of future change in biodiversity patterns in this rapidly warming region.
Shifts in amphibian population dynamics in response to a change in the predator community
Authors: Schmidt Benedikt R. , Băncilă Raluca I. , Hartel Tibor , Grossenbacher Kurt , Schaub Michael 
Published: May 2021

AbstractPredation can affect prey behavior, demography, abundance, and distribution, particularly in lentic freshwater ecosystems. Fish are predators known to reduce the abundance of their prey and to restrict the distribution of species. Using time series which spanned 43 and 22 yr, respectively, we analyzed the effect of a change in the fish predator community on the dynamics of two pond‐breeding amphibian populations (Rana temporaria and Rana dalmatina). Specifically, we used a state‐space time series model which allows for density dependence and observation error, to ask whether the change in predation risk affects population growth rate and the return point around which the populations fluctuate. The results showed that the type of observation error assumed did not affect the biological parameters. We found evidence for density dependence in both populations. The effect of the change in fish predation on population growth rate and the return point was strong in the population where fish invaded a previously fish‐free pond. The effect was weaker in the population where the change was from cyprinid fish to pike. The results showed that fish predation can have strong effects on amphibian population dynamics. The observed population dynamical pattern is phenomenologically similar to alternative stable states.
Size‐, species‐, and site‐specific tree growth responses to climate variability in old‐growth subalpine forests
Authors: Campbell Elizabeth M. , Magnussen Steen , Antos Joseph A. , Parish Roberta 
Published: May 2021

AbstractTree‐ring data have become widely used to model tree growth responses to climate variability and gain insight about the potential effects of global warming on forests. We capitalized on a rare opportunity to develop growth–climate models using tree‐ring data collected from all trees (>4 cm in diameter at breast height) within 50 × 50 m plots established in subalpine old‐growth forests of western Canada. Our objective was to determine how tree growth responses to climate vary among tree size classes, species, and sites. We modeled relationships between times series of annual basal area increment (ΔBA) and yearly climate variables for individual trees; this approach obviated key statistical criticisms of “traditional” tree‐ring analysis methods. Time series of annual basal area increment were detrended a priori for size, age, legacy, and competition effects. We found that the overall climate signal in our time series of ΔBA was weak; <6% of the interannual variance was explained by climate variables. Nevertheless, there were clear patterns in climate–growth relationships related to tree size and species. Relationships between ΔBA and five climate variables increased in strength with tree size class; large trees were most sensitive to annual climate fluctuations and accounted for ~71% of the overall climate effect on growth across all trees and sites. In all stands, ΔBA variance explained by climate variables was stable over the 20th century for large trees but decreased in the 1940s for small trees, indicating a temporal reduction in sensitivity to annual fluctuations in five climate variables. In coastal forests, relationships between ΔBA and climate for Callitropsis nootkatensis were significantly different in direction and magnitude than those of co‐occurring Pinaceae species. The effect of climate on tree growth was idiosyncratic among stands and could not be discriminated by forest type (coastal vs. interior). Our individual‐tree modeling approach adds to a growing body of research providing novel insights about the complexities of tree growth responses to climate variability and the challenges associated with predicting future tree growth and forest productivity using tree‐ring data.
Can Particulate Matter and Nano Metal Oxide Particles Affect the Redox Cycling of Nitrosylcobalamin in Weakly Acidic Aqueous Solution?
Authors: Polaczek Justyna , Stochel Grażyna , van Eldik Rudi 
Published: May 2021

AbstractSince air pollution is one of the most serious environmental problems, the study of the effects of particulate matter (PM) on physiological processes remains to be an important challenge for scientific communities. The presented studies form part of the project ‘Air Pollution versus Autoimmunity: Role of multiphase aqueous Inorganic Chemistry’. In these studies we examined the effect of Standard Reference Material 1648a, supplied by the US National Institute of Standards and Technology (NIST), and its inorganic constituents on the formation of nitrosylcobalamin (CblNO) in the reaction between nitrocobalamin (CblNO2) and ascorbic acid in a weakly acidic medium. We monitored the reaction in the presence of urban NIST PM (SRM 1648a), plasma treated NIST PM (LAP) and a number of metal oxide nanoparticles, including redox active metal oxides. The obtained results clearly demonstrated that the presence of these different nanoparticles affected the rate of formation of CblNO but did not affect the nature of the final product. Special attention was given to systematic studies on the role of inorganic nanoparticles as a part of the selected PM in the reaction between CblNO2 and ascorbic acid.
Eco‐Friendly Alternative to Brining for Sustainable Storage of Table‐Olives Based on the Analyses Done with the Extracted Oil
Authors: Ozilgen Sibel , Aral Selen , Ozilgen Mustafa 
Published: May 2021

AbstractDegree of quality changes in coated and uncoated reference table olives are assed based on the analyses done with the extracted oil at different storage temperatures. The results reveal that storing the table olives after coating with chitosan reduces the product and embeds energy waste. Kinetic studies show that coating delays and slows down the lipid oxidation and decreases the maximum peroxide values attained. At all storage temperatures, the amounts of phenolics retained in the olives are significantly higher in the coated samples when compared with the uncoated references. The results show that coating may also raise the tolerable storage temperature by 14 °C. Coating 10% of the total global table oil production with chitosan may lead to up to 6720 MJ of storage energy savings and 546 t of less CO2 emissions into the atmosphere.Practical Applications: Coating olives with chitosan may improve the quality of the stored oils and reduce the energy requirement of the storage process and consequently reduce the amount of carbon dioxide emissions into the atmosphere compared to in‐brine storage method.
How to Efficiently Remove tert‐butylhydroquinone from Commercial Soybean Oils to Obtain Stripped Oils: Eliminating tert‐butylhydroquinone's Influence on Oxidative Stabilities of Model Oil‐in‐Water Emulsions
Authors: Chen Jiaxin , Li Xin , Kong Baohua , Ma Jinglin , Liu Meiyue , Liu Chengguo , Liu Qian 
Published: May 2021

AbstractThe present study proposes an efficient method to effectively strip tert‐butylhydroquinone (TBHQ) from commercial soybean oils. Ethanol, a typically common and relatively safe organic solvent, can successfully strip TBHQ by employing a liquid‐liquid extraction strategy. The results show that the volume ratio of ethanol to oil is a key factor for stripping efficiency (SE), and 4:1 (v/v) is considered the optimal parameter. When compared with traditional stripping methods via adsorbing materials (such as activated charcoal or alumina powder), the proposed ethanol extraction method can more effectively strip TBHQ from commercial oils with lower adsorption loss and higher SE. Moreover, the model O/W emulsion systems prepared using ethanol stripped oils showed the highest degree of lipid oxidation. The method can completely strip TBHQ from commercial soybean oils, thereby eliminating its influence on oxidative stabilities of model oil‐in‐water emulsions.Practical Applications: The ethanol stripping method can be applied as a pretreatment method to completely strip TBHQ from commercial soybean oils, and subsequently eliminate the influence of TBHQ on lipid oxidation in model O/W emulsion systems during storage.
Cerebroprotein hydrolysate‐I protects senescence‐induced by D‐galactose in PC12 cells and mice
Authors: Zhu Lin , Liu Yingjuan , Wu Xiaolin , Ren Yuqian , Zhang Qinghua , Ren Leiming , Guo Yunliang 
Published: May 2021

AbstractCerebroprotein hydrolysate‐I (CH‐I)，a mixture of peptides extracted from porcine brain tissue，has shown a neuroprotective effect, but its role in brain senescence is unclear. In the present study, we established a senescence model of PC12 cells and mice to investigate the effect of CH‐I on brain senescence via JAK2/STAT3 pathway. The results showed that CH‐I could improve cell viability, inhibit the apoptosis of cells, and reduce the senescence‐positive cells induced by D‐galactose. In vivo, CH‐I improved the learning ability and memory of aging mice, reduced neuronal damage in mice hippocampus. Mechanism studies showed that CH‐I could adjust BDNF protein expressions, activate JAK2/STAT3 pathway, and finally enhance telomerase activity. All these findings indicated that CH‐I showed a neuroprotective effect against brain senescence. These results might provide further reference and support for the application of CH‐I in delaying aging.
High rates of postoperative radiotherapy delay in head and neck cancer before and after Medicaid expansion
Authors: Pang John , Faraji Farhoud , Risa Erik , Mell Loren K. , Houlton Jeffrey J. , Califano Joseph A. 
Published: May 2021

AbstractBackgroundThe objective is to study the effect of Medicaid expansion on postoperative radiation therapy (PORT) delay in patients with head and neck squamous cell carcinoma (HNSCC).MethodsPatients from the National Cancer Database with HNSCC undergoing curative‐intent surgery in the 2 years before and after Medicaid expansion were analyzed (n = 11 717) using the difference‐in‐differences technique to study the effect on PORT delay.ResultsThe rate of PORT delay before and after expansion was 66.0% and 66.9%, respectively. Medicaid patients had more frequent PORT delay than privately insured patients (pre‐expansion 77.2% vs. 59.4%, p < 0.001; post‐expansion 76.5% vs. 60.9%, p < 0.001). Medicaid expansion had no effect on PORT delay [hazard ratio 0.95, 95% confidence interval 0.81–1.12]. Supplemental analyses revealed that pathologic stage, number of treating facilities, and comorbidities were among several factors associated with PORT delay in the cohort.ConclusionPORT delay is unacceptably frequent. Improvement in timely adjuvant therapy requires more than Medicaid expansion.