bluuebunny/crossref_metadata_2025_split huggingface dataset:
Historical harvests reduce neighboring old‐growth basal area across a forest landscape
Authors: Bell David M. , Spies Thomas A. , Pabst Robert 
Published: April 2017

AbstractWhile advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal area patterns of neighboring old‐growth forests to assess the magnitude and scale of harvest edge influence in a forest landscape of western Oregon, USA. We used lidar data and forest plot measurements to construct 30‐m resolution live tree basal area maps in lower and middle elevation mature and old‐growth forests. We assessed how edge influence on total, upper canopy, and lower canopy basal area varied across this forest landscape as a function of harvest characteristics (i.e., harvest size and age) and topographic conditions in the unharvested area. Upper canopy, lower canopy, and total basal area increased with distance from harvest edge and elevation. Forests within 75 m of harvest edges (20% of unharvested forests) had 4% to 6% less live tree basal area compared with forest interiors. An interaction between distance from harvest edge and elevation indicated that elevation altered edge influence in this landscape. We observed a positive edge influence at low elevations (<800 m) and a negative edge influence at moderate to high elevations (>800 m). Surprisingly, we found no or weak effects of harvest age (13–60 yr) and harvest area (0.2–110 ha) on surrounding unharvested forest basal area, implying that edge influence was relatively insensitive to the scale of disturbance and multi‐decadal recovery processes. Our study indicates that the edge influence of past clearcutting on the structure of neighboring uncut old‐growth forests is widespread and persistent. These indirect and diffuse legacies of historical timber harvests complicate forest management decision‐making in old‐growth forest landscapes by broadening the traditional view of stand boundaries. Furthermore, the consequences of forest harvesting may reach across ownership boundaries, highlighting complex governance issues surrounding landscape management of old‐growth forests.
Spatial overlap of shark nursery areas and the salmon farming industry influences the trophic ecology of Squalus acanthias on the southern coast of Chile
Authors: Gaitán‐Espitia Juan Diego , Gómez Daniela , Hobday Alistair J. , Daley Ross , Lamilla Julio , Cárdenas Leyla 
Published: April 2017

AbstractPotential interactions between marine predators and humans arise in the southern coast of Chile where predator feeding and reproduction sites overlap with fisheries and aquaculture. Here, we assess the potential effects of intensive salmon aquaculture on food habits, growth, and reproduction of a common predator, the spiny dogfish—identified as Squalus acanthias via genetic barcoding. A total of 102 (89 females and 13 males) individuals were collected during winter and summer of 2013–2014 from the Chiloé Sea where salmon aquaculture activities are concentrated. The low frequency of males in our study suggests spatial segregation of sex, while immature and mature females spatially overlapped in both seasons. Female spiny dogfish showed a functional specialist behavior as indicated by the small number of prey items and the relative high importance of the austral hake and salmon pellets in the diet. Immature sharks fed more on pellets and anchovies than the larger hake‐preferring mature females. Our results also indicate that spiny dogfish switch prey (anchovy to hake) to take advantage of seasonal changes in prey availability. Despite differences in the trophic patterns of S. acanthias due to the spatial association with intensive salmon farming, in this region, there appears to be no difference in fecundity or size at maturity compared to other populations. Although no demographic effects were detected, we suggest that a range of additional factors should be considered before concluding that intensive aquaculture does not have any impact on these marine predators.
Contamination assessment and the risk associated with the accumulation of trace metals in sediments of the Mitidja plain, Algeria
Authors: Laribi Abdelkader , Mouhouche Brahim , Benayad Tahar , Dehnoun Zahida 
Published: April 2017

This study was carried out to assess the degree of contamination by trace metals in sediments of the main rivers of the eastern Mitidja plain. In order to achieve this objective, the enrichment factor, the geoaccumulation index and the potential ecological risk were calculated. Possible sources of trace metals in sediments were performed using a multivariate statistical analysis. The concentrations of the studied metals decreased in the order of Fe ≫ Zn > Cr > Pb > Ni > Cu> Cd. The results showed that Cd had a higher enrichment factor than the other metals. The geoaccumulation index results of trace metals revealed that the studied sediment were strongly contaminated with Cd, moderately contaminated with Zn and Pb and not contaminated with Cr, Cu, Fe, and Ni. Among the studied trace metals, only the Cd may present an ecological potential risk to the ecosystem. Furthermore, the results indicated a geochemical association of the elements Cr, Fe and Ni, suggesting natural source of these metals. In addition, Cd, Cu, Pb, and Zn appear to have originated from different sources. The results of this study are important for the development of any future strategies to protect the aquatic environment. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1650–1657, 2017
Naringin abates adverse effects of cadmium‐mediated hepatotoxicity: An experimental study using HepG2 cells
Authors: Rathi Visesh Kumar , Das Shubhankar , Parampalli Raghavendra Archana , Rao Bola Sadashiva Satish 
Published: April 2017

AbstractThis study investigated the protective potential of Naringin (NIN) against cadmium chloride (CdCl2) mediated hepatotoxicity using human hepatocellular carcinoma (HepG2) cells. An optimal concentration of NIN (5 μM) was potent enough to confer cytoprotection against CdCl2 (50 μM) as was observed by MTT assay. Preconditioning with NIN maintained redox homeostasis, mitochondrial membrane potential, and reduced apoptosis as marked by decrease in the percentage sub‐G0/G1 and Annexin V‐FITC/propidium iodide positive cells (apoptotic). NIN pretreatment maintained the levels of protein thiol along with endogenous activities of Superoxide dismutase, Glutathione S‐transferase, and Catalase and lowered lipid peroxidation. Decreased Bax/Bcl2 ratio along with reduced Caspase 3 cleavage and Cytochrome c release indicated that NIN conditioning blocked mitochondrial‐mediated apoptosis. Increased Nrf2 and metallothionein (MT) acted as adaptive response in the presence of cadmium. Thus, the protective mechanism of NIN is attributed to its antioxidant potential which aids in redox homeostasis and prevents CdCl2 mediated cytotoxicity.
High‐theabrownins instant dark tea product by Aspergillus niger via submerged fermentation: α‐glucosidase and pancreatic lipase inhibition and antioxidant activity
Authors: Wang Yuwan , Zhang Mingyue , Zhang Zhengzhu , Lu Hengqian , Gao Xueling , Yue Pengxiang 
Published: April 2017

AbstractBACKGROUNDTheabrownins (TB) are bioactive components that are usually extracted from Chinese dark tea, in which they are present at low concentrations. The present study aimed to produce an instant dark tea high in theabrownins via submerged fermentation by the fungus Aspergillus niger. Three fermentation parameters that affect theabrownins content (i.e. inoculum size, liquid–solid ratio and rotation speed) were optimized using response surface methodology.RESULTOptimum fermentation conditions were modeled to be an inoculum of 5.40% (v/v), a liquid–solid ratio of 27.45 mL g−1 and a rotation speed of 184 rpm and were predicted to yield 292.99 g kg−1 TB. Under these experimentally conditions, the TB content of the instant dark tea was 291.93 g kg−1. The antioxidant capacity and α‐glucosidase and pancreatic lipase inhibitory activities of the high‐TB instant black tea were higher than four other typical instant dark tea products.CONCLUSIONThe results of the present study show that careful management of culture conditions can produce a dark tea high in theabrownins. Furthermore, high‐theabrownins instant dark tea could serve as a source of bioactive products and be used in functional foods as an ingredient imparting antioxidant properties and the ability to inhibit pancreatic lipase and α‐glucosidase. © 2017 Society of Chemical Industry
Migratory connectivity of american woodcock using band return data
Authors: Moore Joseph D. , Krementz David G. 
Published: April 2017

ABSTRACTAmerican woodcock (Scolopax minor) are managed as a Central and an Eastern population in the United States and Canada based on band return data showing little crossover between populations or management regions. The observed proportion of crossover between management regions, however, depends on the criteria used to subset the band return data. We analyzed the amount of crossover between management regions using only band return records that represent complete migrations between the breeding and wintering grounds by using only band return records in which the capture took place during the breeding season and the band recovery took place during the wintering season or vice versa (n = 224). Additionally, we applied spatial statistics and a clustering algorithm to investigate woodcock migratory connectivity using this subset of migratory woodcock band return records. Using raw counts, 17.9% of records showed crossover between management regions, a higher proportion than the <5% crossover reported in studies that did not use only migratory band returns. Our results showed woodcock from the breeding grounds in the Central Region largely migrate to destinations within the Central Region, whereas woodcock from the breeding grounds in the Eastern Region migrate to destinations across the entire wintering range and mix with individuals from the Central Region. Using the division coefficient, we estimated that 54% of woodcock from the breeding grounds of the Eastern Region migrate to the Central Region wintering grounds. Our result that many woodcock from separate regions of the breeding grounds mix on the wintering grounds has implications for the 2‐region basis for woodcock management. Elucidating finer scale movement patterns among regions provides a basis for reassessing the need for separate management regions to ensure optimal conservation and management of the species. © 2017 The Wildlife Society.
White‐tailed deer carrying capacity, intercropping switchgrass, and pine plantations
Authors: Loman Zachary G. , Greene Ethan J. , Wheat Bradley R. , Demarais Stephen , Miller Darren A. , Rush Scott A. , Riffell Samuel K. 
Published: April 2017

ABSTRACTSwitchgrass (Panicum virgatum) is a cellulosic feedstock for alternative energy production that can be grown between rows of planted pines (Pinus spp.) within intensively managed forests. Southeastern planted pine occupies 15.8 million ha and thus, switchgrass intercropping could have far‐ranging effects on plant communities and biomass production within these forests if broadly implemented. Such intercropping could lead to alterations to plant communities that may cause bottom‐up ecological changes affecting ecologically, economically, and socially important wildlife, such as white‐tailed deer (Odocoileus virginianus; deer). Therefore, we tested whether intercropping switchgrass in loblolly pine (P. taeda) plantations would cause switchgrass to dominate vegetative biomass thereby decreasing biomass of forages and reducing white‐tailed deer nutritional carrying capacity (NCC), or whether disturbance associated with establishment and harvest of switchgrass would facilitate ruderal forbs, and thereby increase biomass of preferred deer forages and increase NCC. In a randomized complete block design, we assigned 2 treatments (intercropped switchgrass and a standard pine management control) to 4 replicates of 10‐ha experimental units in Kemper County, Mississippi during summers of 2011−2015. We detected 323 plant species. Intercropping switchgrass had little effect on plant biomass production, and did not affect white‐tailed deer NCC at a maintenance diet of 6% crude protein. Intercropping provided additional disturbance allowing high‐protein content ruderal plants to colonize, and temporarily increased (3 yr) deer NCC at the 14% crude protein diet considered necessary to support lactation. However, concomitant with a sharp increase in switchgrass biomass in the third year of the study, NCC dropped to levels similar to traditionally managed pine stands. Switchgrass intercropping is not a reliable means of increasing deer NCC as a management strategy but does not appear to reduce carrying capacity in the short‐term relative to standard intensive pine management. © 2017 The Wildlife Society.
Shelf‐basin gradients shape ecological phytoplankton niches and community composition in the coastal Arctic Ocean (Beaufort Sea)
Authors: Ardyna M. , Babin M. , Devred E. , Forest A. , Gosselin M. , Raimbault P. , Tremblay J.‐É. 
Published: April 2017

AbstractThe contiguous Arctic shelf is the green belt of the Arctic Ocean. Phytoplankton dynamics in this environment are driven by extreme physical gradients and by rapid climate change, which influence light and nutrient availability as well as the growth and ecological characteristics of phytoplankton. A large dataset collected across the Canadian Beaufort Shelf during summer 2009 was analyzed to assess how the interplay of physical and biogeochemical conditions dictates phytoplankton niches and trophic regimes. Nonmetric multidimensional scaling and cluster analysis demonstrated marked partitioning of phytoplankton diversity. Elevated phytoplankton biomass (∼ 2.41 μg Chl a L−1) was observed in association with the surface mixed layer near the coast, close to the mouth of the Mackenzie River, and at the shelf‐break as a result of nutrient‐rich Pacific water intrusions. The coastal communities were supported by high levels of nitrogen nutrients and were taxonomically uniform, with diatoms accounting for 95% of total cell numbers. By contrast, adjacent oceanic waters were characterized by low autotrophic biomass near the surface (∼ 0.09 μg Chl a L−1) and below the mixed layer (∼ 0.23 μg Chl a L−1) due to mainly nutrient limitation. However, the oceanic community was more diverse with a mixed assemblage of diatoms and small mixotrophs/heterotrophs near the surface and a predominance of autotrophic nanoflagellates at depth. We conclude that as climate change intensifies freshening and stratification in the Western Arctic Ocean, coastal hotspots of high autotrophic productivity may play an even greater role in supporting Arctic marine ecosystems while offshore environments become increasingly oligotrophic.
Effect of Isomeric Structures on Photovoltaic Performance of D–A Copolymers
Authors: Xie Fangyuan , He Dan , Pan Han , Jiang Jiaxing , Ding Liming 
Published: April 2017

Two donor–acceptor copolymers based on isomeric acceptor units, [7,7′‐bithieno[2′,3′:4,5]thieno[2,3‐d]thieno[3,2‐b]pyridine]‐5,5′(4H,4′H)‐dione (BTTP) and [2,2′‐bithieno[2′,3′:4,5]thieno[2,3‐d]thieno[3,2‐b]pyridine]‐5,5′(4H,4′H)‐dione (iBTTP), are developed to study the effect of isomeric structures on photovoltaic performance. Compared with PBDTBTTP, PBDTiBTTP possesses a smaller bandgap for good light harvesting and a better π–π stacking for higher hole mobility. PBDTiBTTP solar cells present balanced mobilities and good nanoscale phase separation, giving a power conversion efficiency (PCE) of 6.51%, with higher short‐circuit current (Jsc) and fill factor (FF).
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Exploration of Ideal Polymer Networks
Authors: Shibayama Mitsuhiro 
Published: April 2017

SummaryThe history of exploration of ideal polymer networks is reviewed, followed by a demonstration of fabrication and applications of novel polymer networks free from defects/entanglements. The networks, we call, are Tetra‐PEG gels, consisting of two types of tetra‐arm poly(ethylene glycol) (PEG) prepolymers that have mutually reactive amine (Tetra‐PEG‐NH2) and activated ester (Tetra‐PEG‐NHS) terminal groups, respectively. Here NHS represents N‐hydroxysuccinimide. The novelty lies in “cross‐end‐coupling” of symmetrical tetra‐arm PEGs having complementary end groups. Small‐angle neutron scattering (SANS) results on Tetra‐PEG gels, together with mechanical properties and swelling behaviors, strongly suggest that thus prepared Tetra‐PEG gels are near‐“ideal” polymer networks with very small fractions of defects. In order to answer the reasons why such a structure could be formed, the kinetics of gelation was investigated by IR, UV, and time‐resolved rheological and SANS measurements. Furthermore, fabrication of Tetra‐PEG ion gels, having good mechanical properties, is demonstrated.
Amphiphilic Polymer Conetworks Based on Interconnected Hydrophobic Star Block Copolymers: Synthesis and Characterization
Authors: Kepola Eleni J. , Kyriacou Kyriacos , Patrickios Costas S. , Simon Miriam , Gradzielski Michael , Kushnir Michelle , Wesdemiotis Chrys 
Published: April 2017

SummaryHerein we report on the preparation and structural characterization of six amphiphilic polymer conetworks (APCN) based on end‐linked amphiphilic “core‐first” star block copolymers, comprising methyl methacrylate and 2‐(dimethylamino)ethyl methacrylate as the monomer repeating units in the hydrophobic and hydrophilic blocks, respectively. The various APCNs differed either in the arm composition or in the arm molecular weight. APCN synthesis was accomplished via the one‐pot, sequential group transfer polymerization (GTP) of cross‐linker, hydrophobic monomer, hydrophilic monomer, and cross‐linker again. The soluble precursors to the APCNs, i.e., the star homopolymers, the star block copolymers and the initial cross‐linker cores, were characterized in terms of their composition, size and size dispersity. The degrees of swelling in tetrahydrofuran were found to increase with the molecular weight of the arms of the stars of the APCNs, whereas the degrees of swelling in water increased with the content in hydrophilic units in the arms of the constituting stars. Small‐angle neutron scattering (SANS) indicated that most APCNs nanophase separated in D2O. The structure and size of the hydrophobic domains determined by fitting the SANS data to an appropriate model could be correlated with the molecular architecture of the APCNs. Finally, polarized light microscopy showed that all APCNs were birefringent both in water and in the dried state.
Structure and Properties of Cartilage Proteoglycans
Authors: Horkay Ferenc , Basser Peter J. , Hecht Anne‐Marie , Geissler Erik 
Published: April 2017

SummaryThe most abundant cartilage proteoglycan is aggrecan, a bottlebrush shaped molecule that possesses over 100 glycosaminoglycan (chondroitin sulfate and keratan sulfate) chains. The side‐chains are linear sulfated polysaccharides that are negatively charged under physiological conditions. Aggrecan interacts with hyaluronic acid (HA) to form large aggregates. Osmotic pressure measurements and rheological measurements are used to study the static and dynamic behavior of aggrecan assemblies at the macroscopic length scales. The microscopic properties of aggrecan solutions are determined by small angle neutron scattering, and static and dynamic light scattering (SLS and DLS). In dilute solutions aggrecan forms microgels with a diffuse boundary, composed of loosely connected clusters. The osmotic pressure of the aggrecan‐HA system decreases with increasing HA content. DLS yields a relaxation rate that varies as q3, arising from internal modes in the microgel. The relaxation rate in the solutions of the aggrecan‐HA complex is slightly greater than in the pure aggrecan solution.
Polarimetric Doppler radar analysis of squall line systems crossing Salento Peninsula
Authors: Congedo F. , Prodi F. , Pasqualucci F. , Trivellone G. 
Published: April 2017

ABSTRACTA detailed observational study of squall line thunderstorms, a particular form of mesoscale convective systems arranged in a line that repeatedly affected Salento Peninsula (southern Apulia, Italy) throughout 2015, is presented and discussed. Specifically, three relevant events that occurred in January, at the end of September and in October are described, combining thermodynamic and synoptic analysis with radar imagery delivered by the cutting‐edge polarimetric Doppler radar recently installed in Torchiarolo, in the central part of Salento Peninsula. Reported observational information reveals that, regardless of the season of the year, convergence along an approaching cold front represents the common initiating mechanism leading to the formation of linear convective systems. Furthermore, high resolution Doppler data provided by Torchiarolo radar allows better detection and prompt recognition of severe weather signatures, such as bow echoes and cyclonic mesovortices, commonly associated with squall line thunderstorms. Therefore, the present study clearly confirms the key role of the new advanced weather radar installed in Torchiarolo which thus represents a powerful tool giving researchers and forecasters valuable information about kinematic and microphysical properties of severe weather systems crossing Apulia region, especially Salento Peninsula.
A molecular mechanics and ab initio prediction of the 1H chemical shifts of pinanes
Authors: Abraham Raymond J. , Ashley Cooper M. 
Published: April 2017

Molecular mechanics calculations plus the application of a refined Karplus equation gave the conformations of 19 pinanes. These range from a Y‐shaped geometry in the apopinene and α‐pinene series to a pseudo chair conformation in β‐pinene, nopinone and verbanone, a flattened chair in pinocarvone and the pinocarveols and a distorted Y shape for iso‐verbanone.These structures were then used as input to predict the 1H chemical shifts of these compounds by semi‐empirical (1H‐NMR spectra (HSPEC)) and ab initio gauge‐invariant atomic orbital (GIAO) calculations, the latter at the B3LYP hybrid density functional theory level using 6‐31++G** basis set. The two methods gave generally good agreement with the 184 observed shifts with root mean square (RMS) errors 0.07 ppm (HSPEC) and 0.10 ppm (GIAO), but the GIAO calculations gave several significant (>0.25 ppm) errors. One was for the H3 proton in apopinenone and other α,β unsaturated ketones; the others occurred for protons in close proximity to hydroxyl groups. To provide more information, smaller analogues of known geometry and chemical shifts were subject to the same analysis. In cyclopentenone, the Gaussian geometry gave good agreement with the observed shifts, but the MMFF94, MMX and MM3 geometries all gave errors for different protons. These results show clearly that the molecular geometries of the α,β unsaturated ketones are responsible for the errors. The errors for the alcohols were examined using ethanol as model and were shown to be due to the different possible conformations of the OH group. Similar GIAO calculations on substituted methanes gave good agreement for the methyl compounds but poor agreement for di and tri halosubstituted methanes.The aforementioned method of molecular mechanics plus GIAO calculations is shown to be a very useful tool for the investigation of molecular geometries and conformations. However, multihalogen compounds may require different basis sets for accurate calculations. Copyright © 2017 John Wiley & Sons, Ltd.