bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scaling marine fish movement behavior from individuals to populations
Authors: Griffiths Christopher A. , Patterson Toby A. , Blanchard Julia L. , Righton David A. , Wright Serena R. , Pitchford Jon W. , Blackwell Paul G. 
Published: June 2018

AbstractUnderstanding how, where, and when animals move is a central problem in marine ecology and conservation. Key to improving our knowledge about what drives animal movement is the rising deployment of telemetry devices on a range of free‐roaming species. An increasingly popular way of gaining meaningful inference from an animal's recorded movements is the application of hidden Markov models (HMMs), which allow for the identification of latent behavioral states in the movement paths of individuals. However, the use of HMMs to explore the population‐level consequences of movement is often limited by model complexity and insufficient sample sizes. Here, we introduce an alternative approach to current practices and provide evidence of how the inclusion of prior information in model structure can simplify the application of HMMs to multiple animal movement paths with two clear benefits: (a) consistent state allocation and (b) increases in effective sample size. To demonstrate the utility of our approach, we apply HMMs and adapted HMMs to over 100 multivariate movement paths consisting of conditionally dependent daily horizontal and vertical movements in two species of demersal fish: Atlantic cod (Gadus morhua; n = 46) and European plaice (Pleuronectes platessa; n = 61). We identify latent states corresponding to two main underlying behaviors: resident and migrating. As our analysis considers a relatively large sample size and states are allocated consistently, we use collective model output to investigate state‐dependent spatiotemporal trends at the individual and population levels. In particular, we show how both species shift their movement behaviors on a seasonal basis and demonstrate population space use patterns that are consistent with previous individual‐level studies. Tagging studies are increasingly being used to inform stock assessment models, spatial management strategies, and monitoring of marine fish populations. Our approach provides a promising way of adding value to tagging studies because inferences about movement behavior can be gained from a larger proportion of datasets, making tagging studies more relevant to management and more cost‐effective.
Best hyperspectral indices for assessing leaf chlorophyll content in a degraded temperate vegetation
Authors: Peng Yu , Fan Min , Wang Qinghui , Lan Wenjuan , Long Yating 
Published: June 2018

AbstractExtensive studies have focused on assessing leaf chlorophyll content through spectral indices; however, the accuracy is weakened by limited wavebands and coarse resolution. With hundreds of wavebands, hyperspectral data can substantially capture the essential absorption features of leaf chlorophyll; however, few such studies have been conducted on same species in various degraded vegetations. In this investigation, complete combinations of either original reflectance or first‐order derivative spectra we conducted a complete combination on either original reflectance or its first‐order derivative value from 350 to 1000 nm to quantify leaf total chlorophyll (Chll), chlorophyll‐a (Chla), and chlorophyll‐b (Chlb) contents. This was performed using three hyperspectral datasets collected in situ from lightly, moderately, and severely degraded vegetations in temperate Helin County, China. Suitable combinations were selected by comparing the numbers of significant correlation coefficients with leaf Chll, Chla, and Chlb contents. The combinations of reflectance difference (Dij), normalized differences (ND), first‐order derivative (FD), and first‐order derivative difference (FD(D)) were found to be the most effective. These sensitive band‐based combinations were further optimized by means of a stepwise linear regression analysis and were compared with 43 empirical spectral indices, frequently used in the literature. These sensitive band‐based combinations on hyperspectral data proved to be the most effective indices for quantifying leaf chlorophyll content (R2 > 0.7, p < 0.01), demonstrating great potential for the use of hyperspectral data in monitoring degraded vegetation at a fine scale.
Discovery of a multispecies shark aggregation and parturition area in the Ba Estuary, Fiji Islands
Authors: Vierus Tom , Gehrig Stefan , Brunnschweiler Juerg M. , Glaus Kerstin , Zimmer Martin , Marie Amandine D. , Rico Ciro 
Published: June 2018

AbstractPopulation declines in shark species have been reported on local and global scales, with overfishing, habitat destruction and climate change posing severe threats. The lack of species‐specific baseline data on ecology and distribution of many sharks, however, makes conservation measures challenging. Here, we present a fisheries‐independent shark survey from the Fiji Islands, where scientific knowledge on locally occurring elasmobranchs is largely still lacking despite the location's role as a shark hotspot in the Pacific. Juvenile shark abundance in the fishing grounds of the Ba Estuary (north‐western Viti Levu) was assessed with a gillnet‐ and longline‐based survey from December 2015 to April 2016. A total of 103 juvenile sharks identified as blacktip Carcharhinus limbatus (n = 57), scalloped hammerhead Sphyrna lewini (n = 35), and great hammerhead Sphyrna mokarran (n = 11) sharks were captured, tagged, and released. The condition of umbilical scars (68% open or semihealed), mean sizes of individuals (±SD) (C. limbatus: 66.5 ± 3.8 cm, S. lewini: 51.8 ± 4.8 cm, S. mokarran 77.4 ± 2.8 cm), and the presence of these species over recent years (based on fishermen interviews), suggest that the Ba Estuary area is a critical habitat for multiple species that are classified as “Near Threatened” or “Endangered.” Specifically, the area likely acts as a parturition ground over the studied period, and potentially as a subsequent nursery area. We identified subareas of high abundance and found that temperature, salinity and depth acted as small‐scale environmental drivers of shark abundance. The data suggests a tendency for species‐specific spatial use, both horizontally (i.e., between sampling areas) and vertically (i.e., across the water column). These results enhance the understanding of shark ecology in Fiji and provide a scientific basis for the implementation of local conservation strategies that contribute to the protection of these threatened species.
Gene flow and Andean uplift shape the diversification of Gasteracantha cancriformis (Araneae: Araneidae) in Northern South America
Authors: Salgado‐Roa Fabian C. , Pardo‐Diaz Carolina , Lasso Eloisa , Arias Carlos F. , Solferini Vera Nisaka , Salazar Camilo 
Published: June 2018

AbstractThe Andean uplift has played a major role in shaping the current Neotropical biodiversity. However, in arthropods other than butterflies, little is known about how this geographic barrier has impacted species historical diversification. Here, we examined the phylogeography of the widespread color polymorphic spider Gasteracantha cancriformis to evaluate the effect of the northern Andean uplift on its divergence and assess whether its diversification occurred in the presence of gene flow. We inferred phylogenetic relationships and divergence times in G. cancriformis using mitochondrial and nuclear data from 105 individuals in northern South America. Genetic diversity, divergence, and population structure were quantified. We also compared multiple demographic scenarios for this species using a model‐based approach (Phrapl) to determine divergence with or without gene flow. At last, we evaluated the association between genetic variation and color polymorphism. Both nuclear and mitochondrial data supported two well‐differentiated clades, which correspond to populations occurring on opposite sides of the Eastern cordillera of the Colombian Andes. The final uplift of this cordillera was identified as the most likely force that shaped the diversification of G. cancriformis in northern South America, resulting in a cis‐ and trans‐Andean phylogeographic structure for the species. We also found shared genetic variation between the cis‐ and trans‐Andean clades, which is better explained by a scenario of historical divergence in the face of gene flow. This has been likely facilitated by the presence of low‐elevation passes across the Eastern Colombian cordillera. Our work constitutes the first example in which the Andean uplift coupled with gene flow influenced the evolutionary history of an arachnid lineage.
The future of cold‐adapted plants in changing climates: Micranthes (Saxifragaceae) as a case study
Authors: Stubbs Rebecca L. , Soltis Douglas E. , Cellinese Nico 
Published: June 2018

AbstractResearch has shown species undergoing range contractions and/or northward and higher elevational movements as a result of changing climates. Here, we evaluate how the distribution of a group of cold‐adapted plant species with similar evolutionary histories changes in response to warming climates. We selected 29 species of Micranthes (Saxifragaceae) representing the mountain and Arctic biomes of the Northern Hemisphere. For this analysis, 24,755 data points were input into ecological niche models to assess both present fundamental niches and predicted future ranges under climate change scenarios. Comparisons were made across the Northern Hemisphere between all cold‐adapted Micranthes, including Arctic species, montane species, and species defined as narrow endemics. Under future climate change models, 72% of the species would occupy smaller geographical areas than at present. This loss of habitat is most pronounced in Arctic species in general, but is also prevalent in species restricted to higher elevations in mountains. Additionally, narrowly endemic species restricted to high elevations were more susceptible to habitat loss than those species found at lower elevations. Using a large dataset and modeling habitat suitability at a global scale, our results empirically model the threats to cold‐adapted species as a result of warming climates. Although Arctic and alpine biomes share many underlying climate similarities, such as cold and short growing seasons, our results confirm that species in these climates have varied responses to climate change and that key abiotic variables differ between these two habitats.
A genetic analysis of dragonfly population structure
Authors: Phillips Payton , Swanson Bradley J. 
Published: June 2018

AbstractDragonflies reside in both aquatic and terrestrial environments, depending on their life stage, necessitating the conservation of drastically different habitats; however, little is understood about how nymph and adult dragonflies function as metapopulations within connected habitat. We used genetic techniques to examine nymphs and adults within a single metapopulation both spatially and temporally to better understand metapopulation structure and the processes that might influence said structure. We sampled 97 nymphs and 149 adult Sympetrum obtrusum from eight locations, four aquatic, and four terrestrial, at the Pierce Cedar Creek Institute in Southwest Michigan over two summers. We performed AFLP genetic analysis and used the Bayesian analysis program STRUCTURE to detect genetic clusters from sampled individuals. STRUCTURE detected k = u4 populations, in which nymphs and adults from the same locations collected in different years did not necessarily fall into the same clusters. We also evaluated grouping using the statistical clustering analyses NMDS and MRPP. The results of these confirmed findings from STRUCTURE and emphasized differences between adults collected in 2012 and all other generations. These results suggest that both dispersal and a temporal cycle of emergence of nymphs from unique clusters every other year could be influential in structuring dragonfly populations, although our methods were not able to fully distinguish the influences of either force. This study provides a better understanding of local dragonfly metapopulation structure and provides a starting point for future studies to investigate the spatial and temporal mechanisms controlling metapopulation structure. The results of the study should prove informative for managers working to preserve genetic diversity in connected dragonfly metapopulations, especially in the face of increasing anthropogenic landscape changes.
Multiple anthropogenic interventions drive puma survival following wolf recovery in the Greater Yellowstone Ecosystem
Authors: Elbroch L. Mark , Marescot Lucile , Quigley Howard , Craighead Derek , Wittmer Heiko U. 
Published: June 2018

AbstractHumans are primary drivers of declining abundances and extirpation of large carnivores worldwide. Management interventions to restore biodiversity patterns, however, include carnivore reintroductions, despite the many unresolved ecological consequences associated with such efforts. Using multistate capture–mark–recapture models, we explored age‐specific survival and cause‐specific mortality rates for 134 pumas (Puma concolor) monitored in the Greater Yellowstone Ecosystem during gray wolf (Canis lupus) recovery. We identified two top models explaining differences in puma survivorship, and our results suggested three management interventions (unsustainable puma hunting, reduction in a primary prey, and reintroduction of a dominant competitor) have unintentionally impacted puma survival. Specifically, puma survival across age classes was lower in the 6‐month hunting season than the 6‐month nonhunting season; human‐caused mortality rates for juveniles and adults, and predation rates on puma kittens, were higher in the hunting season. Predation on puma kittens, and starvation rates for all pumas, also increased as managers reduced elk (Cervus elaphus) abundance in the system, highlighting direct and indirect effects of competition between recovering wolves and pumas over prey. Our results emphasize the importance of understanding the synergistic effects of existing management strategies and the recovery of large, dominant carnivores to effectively conserve subordinate, hunted carnivores in human‐dominated landscapes.
Initial performance evaluation of centimeter‐class augmentation system using Quasi‐Zenith Satellite System
Authors: Namie Hiromune , Okamoto Osamu , Kubo Nobuaki , Yasuda Akio 
Published: June 2018

AbstractOn September 11, 2010, the Quasi‐Zenith Satellite (QZS) “Michibiki” was launched from the Tanegashima island as the first satellite for positioning in Japan. We have attempted to fix positions using LEX data with centimeter‐class augmentation service for centimeter‐level positioning augmentation signal via Michibiki. The authors tried to fix positions by using LEX data at a stationary point and in a moving car in real time and with postprocessing. They could confirm no more than 2.22 cm as the average positioning error and discrepancy of postpositioning.
Blood flow simulation during flow‐mediated dilation
Authors: Asami Naoya , Yamazaki Yoichi , Kamiyama Yoshimi 
Published: June 2018

AbstractEndothelial dysfunction is known to be the early stage of arteriosclerosis. The flow‐mediated dilation (FMD) test is the most commonly used method to diagnose the endothelial function. The test measures the maximum vasodilation (FMD response) on the brachial artery induced by the increases in blood flow after cuff deflation on the forearm. The vessel diameter must be captured clearly with the ultrasonic probe during the test. The vasodilation is induced in response to changes in the mechanical property of the vessel wall due to the blood flow stimulation. The changes are supposed to affect the pulsatile flow, but the influence of continuous behavior of vascular property on hemodynamics has not been clarified. In this study, in order to clarify the influence of the FMD response on hemodynamics, we propose a mathematical model that can simulate hemodynamics and vasomotor responses. As a result, it was shown that vessel wall dynamics affected the pulsatile flow. This result suggests that the endothelial function can be evaluated from blood flow.
The food web perspective on aquatic biofilms
Authors: Weitere Markus , Erken Martina , Majdi Nabil , Arndt Hartmut , Norf Helge , Reinshagen Michael , Traunspurger Walter , Walterscheid Anja , Wey Jennifer K. 
Published: June 2018

AbstractBiofilms, the complex communities of microbiota that live in association with aquatic interfaces, are considered to be hotspots of microbial life in many aquatic ecosystems. Although the importance of attached algae and bacteria is widely recognized, the role of the highly abundant biofilm‐dwelling micrograzers (i.e., heterotrophic protists and small metazoans) is poorly understood. Studies often highlight the resistance of bacterial biofilms to grazing within the microbial food web and therefore argue that the micrograzers have a modulating role (i.e., have effects on biofilm phenotype) rather than a direct trophic role within biofilms. In the present review, we show that this view comes too short, and we establish a conceptual framework of biofilm food webs consisting of three major elements. (1) Energy pathways and subsidization from plankton. As inhabitants of interfaces, biofilm‐dwelling grazers potentially access both planktonic organisms and surface‐associated organisms. They can play an important role in importing planktonic production into the biofilm food web and thus in the coupling of the planktonic and benthic food webs. Nevertheless, specialized grazers are also able to utilize significant amounts of autochthonous biofilm production. (2) Horizontal complexity of the basal food web. While bacteria and algae within biofilms are edible in general, food quality and accessibility of both bacteria and algae can differ considerably between different prey phenotypes occurring during biofilm formation with respect to morphology, chemical defense, and nutrient stoichiometry. Instead of considering bacteria and algae within biofilms to be generally resistant to feeding by micrograzers, we suggest considering a horizontal food‐quality axis to be at the base of biofilm food webs. This food quality gradient is probably associated with increasing costs for the micrograzers. (3) Vertical food web complexity and food chain length. In addition to the consumption of bacteria and algae, many predatory micrograzers exist within biofilm food webs. With the help of video microscopy, we were able to demonstrate the existence of a complex food web with several trophic levels within biofilms. Our conceptual framework should assist in integrating food web concepts and processes into whole‐biofilm budgets and in understanding food‐web‐related interactions within biofilms.
Synthesis, characterization, and crystal structure of novel bulky phenyl‐bridged α‐diimine binucleating ligands
Authors: Mechria Ali , Msaddek Moncef 
Published: June 2018

AbstractA series of sterically and electronically modulated phenyl‐bridged α‐diimine ligands L1–L6 of the general formula Ar‐N=C(Me)‐C(Me)=N‐C6H4‐N=C(Me)‐C(Me)=N‐Ar have been synthesized (L1 : Ar = 2,6‐iPr2‐C6H3; L2: Ar = 2,6‐Me2‐C6H3; L3: 4‐Me‐C6H4; L4: Ar = 4‐Et‐C6H4; L5: Ar = 2,4,6‐Cl3‐C6H2; L6: Ar = 4‐Cl‐C6H4). All of which have been characterized by 1H NMR, 13C NMR, IR, and elemental analysis. In addition, the effect of the electronic modification was studied by UV–Vis spectroscopy, and the structure of a representative ligand was confirmed by single‐crystal X‐ray diffraction. Moreover, a DFT electronic structure of the same ligand has been determined.
Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States
Authors: Clow David W. , Mast M. Alisa , Sickman James O. 
Published: June 2018

AbstractTransit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in mountains of the western United States based on differences in the amplitude of the seasonal signal of δ18O in streamflow and precipitation. Results were statistically compared with catchment characteristics to elucidate controlling mechanisms. Transit times also were compared with stream solute concentrations to test the hypothesis that transit times are a primary influence on weathering rates and biological assimilation of atmospherically deposited N. Results indicate that transit times in the study catchments are strongly related to soil, vegetation, and topographic characteristics, with barren terrain (bare rock and talus) and steep slopes linked to high Fyw and short MTT, whereas forest soil (hydrogroup B) was linked to low Fyw and greater MTT. Concentrations of silicate weathering products (Na+ and Si) were negatively related to Fyw and barren terrain, and positively related to MTT and forest soil, supporting the concept that weathering fluxes and buffering capacity tend to be low in alpine areas due to short transit times. Nitrate concentrations were positively related to N deposition, catchment slope, and barren terrain, and negatively related to forest, indicating that hydrologic and/or biogeochemical processes associated with steep slopes limit uptake of atmospherically deposited N by biota. Interannual and seasonal variability in transit times and source water contributions in the study catchments was substantial, reflecting the influence of strong temporal variations in snowmelt inputs in high‐elevation catchments of the western United States. Results from this study confirm that short transit times in these areas are a key reason they are highly sensitive to atmospheric pollution and climate change.
Production, characterization and testing of antibacterial PVA membranes loaded with HA‐Ag3PO4 nanoparticles, produced by SC‐CO2 phase inversion
Authors: Baldino Lucia , Aragón Javier , Mendoza Gracia , Irusta Silvia , Cardea Stefano , Reverchon Ernesto 
Published: June 2018

AbstractBACKGROUNDSilver‐loaded hydroxyapatite nanoparticles were incorporated into poly(vinyl alcohol) (PVA) membranes obtained by supercritical CO2 (SC‐CO2) assisted phase inversion. Ag3PO4 crystals of 2.2 ± 0.6 nm were dispersed in synthesized needle‐like hydroxyapatite nanoparticles (20 × 65 nm) and were uniformly deposited on the internal surfaces of the PVA membranes. Operative conditions to produce membranes by SC‐CO2, PVA concentration and the effect on membrane porosity and morphology were studied.RESULTSSolutions at 20% w/w PVA produced membranes with cellular morphology and nanoporous walls, whereas 30% and 50% w/w solutions produced nanostructured membranes. Silver ions were released from PVA membranes mainly by diffusion according to the Peppas–Sahlin model. Membranes obtained at 20% w/w PVA showed a significant E. coli inhibition at an Ag concentration of 9 ppm, reaching the minimal inhibitory concentration (MIC) and improving the bactericidal activity of the nanoparticles.CONCLUSIONA concentration of Ag3PO4 crystals of about 22 ppm was calculated as being capable of completely destroying these bacteria, reaching the minimum bactericidal concentration (MBC). © 2018 Society of Chemical Industry