bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral efficiency improvement with SISO and SIMO in M‐QAM over millimeter‐wave links
Authors: Al‐Nahhal Mohamed , Ismail Tawfik , Nasr Mohamed E. 
Published: January 2019

SummaryThis paper proposes a spectral efficiency improvement technique for millimeter wave (mmWave) links. The proposed technique provides an efficient utilization of the mmWave link capacity. This technique is applied in three cases the single‐input single‐output (SISO), single‐input multiple‐output (SIMO) with the maximal ratio combining and with the equal gain combining. The M‐ary quadrature amplitude modulation scheme is used in our work. The power series expansion is used for deriving closed‐form expressions for bit error rate (BER) performances in all studied cases. The BER closed‐form expressions are confirmed by the numerical solution of the integral equations. The simulation results show that a high spectral efficiency can be accomplished by the proposed technique. As well as the derived expressions closely match with the numerical solution of integration expressions at different values of modulations order the Rician factor. For instance, the spectral efficiency gain achievement is 8 at signal‐to‐noise ratio (SNR) equals 34 dB in the case of SISO system whereas in the case of SIMO system, the same gain is achieved at SNR equals 24 dB. As well as the BER performance is enhanced from 1.188 × 10−4, 7.112 × 10−4, 4.164 × 10−3, and 3.286 × 10−2 to 8.717 × 10−16, 1.119 × 10−12, 1.308 × 10−9, and 4.905 × 10−6 for M = 4, 16, 64, and 256, respectively, at SNR equals 30 dB.
Without management interventions, endemic wet‐sclerophyll forest is transitioning to rainforest in World Heritage listed K’gari (Fraser Island), Australia
Authors: Krishnan Vithya , Robinson Nicole , Firn Jennifer , Applegate Grahame , Herbohn John , Schmidt Susanne 
Published: January 2019

AbstractWet‐sclerophyll forests are unique ecosystems that can transition to dry‐sclerophyll forests or to rainforests. Understanding of the dynamics of these forests for conservation is limited. We evaluated the long‐term succession of wet‐sclerophyll forest on World Heritage listed K'gari (Fraser Island)—the world's largest sand island. We recorded the presence and growth of tree species in three 0.4 hectare plots that had been subjected to selective logging, fire, and cyclone disturbance over 65 years, from 1952 to 2017. Irrespective of disturbance regimes, which varied between plots, rainforest trees recruited at much faster rates than the dominant wet‐sclerophyll forest trees, narrowly endemic speciesSyncarpia hilliiand more commonLophostemon confertus.Syncarpia hilliidid not recruit at the plot with the least disturbance and recruited only in low numbers at plots with more prominent disturbance regimes in the ≥10 cm at breast height size.Lophostemon confertusrecruited at all plots but in much lower numbers than rainforest trees. Only fiveL. confertuswere detected in the smallest size class (<10 cm diameter) in the 2017 survey. Overall, we find evidence that more pronounced disturbance regimes than those that have occurred over the past 65 years may be required to conserve this wet‐sclerophyll forest, as without intervention, transition to rainforest is a likely trajectory. Fire and other management tools should therefore be explored, in collaboration with Indigenous landowners, to ensure conservation of this wet‐sclerophyll forest.
Asian needle ant (Brachyponera chinensis) and woodland ant responses to repeated applications of fuel reduction methods
Authors: Campbell Joshua W. , Grodsky Steven M. , Halbritter Dale A. , Vigueira Patrick A. , Vigueira Cynthia C. , Keller Oliver , Greenberg Cathryn H. 
Published: January 2019

AbstractAnts (Formicidae: Hymenoptera) are important components of forest ecosystems and can be affected by fuel reduction forest management practices. We assessed the impact of repeated applications of fuel reduction treatments on abundance and diversity of ants within upland mixed‐hardwood forests in the Southern Appalachian Mountains in North Carolina, USA. We established three replicate blocks (~56 ha each) and split each block into four fuel reduction treatments, which included prescribed burning (B), mechanical felling (M), a combination of prescribed burning and mechanical felling (MB), and a control (C; i.e., no treatment). We implemented treatments multiple times (two mechanical thinnings and four prescribed burns) over the course of a 15‐yr period. Due to tree mortality and resultant canopy gaps from high‐severity burns, forest structure was dramatically altered in MB. Over a 3‐yr period (2014–2016), we captured 54,219 ants comprised of 23 genera using pitfall and colored pan traps.Prenolepis impariswas the most common ant species collected, and it was significantly lower in abundance in MB than all other treatments. However, the non‐native speciesBrachyponera chinensiswas more abundant in MB than all other treatments. Thus, some fuel reduction treatments may have consequences for invasive ant colonization in forests. Most ant taxa did not differ in abundance among treatments, suggesting that some fuel reduction practices may affect some, but not all ant species. Our results indicate that some fuel reduction treatments can alter forest ant communities, thus contributing to changing forest ecosystem dynamics. Monitoring of ants and other bioindicators after repeated rounds of fuel reduction treatments could provide useful knowledge that can be used to help balance forest management and biological diversity.
Plant–pollinator networks in grassland working landscapes reveal seasonal shifts in network structure and composition
Authors: Bendel Cayla R. , Kral‐O'Brien Katherine C. , Hovick Torre J. , Limb Ryan F. , Harmon Jason P. 
Published: January 2019

AbstractDeclines in native bee populations can limit pollination services that support native plant communities and global food production. Mitigating the impacts on pollinators and ecosystems requires conservation actions that promote biodiversity and remain practical for producers. We investigated plant–pollinator interaction networks in working grassland landscapes, managed for cattle production and biodiversity, to advance conservation of pollinators in grazed systems. We compared and plotted interactions at the network level. We then used a regression framework to evaluate the influence of floristic availability on pollinator abundance in our system. Overall, we detected seasonal shifts at the network level, with increased specialization between flowers and bees occurring at the end of the sampling season. Furthermore, the response to floristic resources differed between honey bees (Apis mellifera) and native bees. While honey bee abundance increased with exotic floral abundance, native bee abundance showed no relationship with floral abundance and instead was positively associated with floral richness in our system. These findings could be an indication of seasonal shifts in bee activity and interactions with plants or a response to the subset of available resources in grazed systems. These interpretations, along with the detected difference in resource use between honey bees and native bees, suggest foraging preferences differ between these two groups and could influence conservation and management strategies. Furthermore, it demonstrates a need to consider how management practices could influence bee communities differentially across the growing season and suggests conservation actions should promote native floristic resources to benefit native bees.
Influence of weak groups on polyelectrolyte mobilities
Authors: Sean David , Landsgesell Jonas , Holm Christian 
Published: January 2019

AbstractThe ionization of dissociable groups in weak polyelectrolytes does not occur in a homogenous fashion. Monomer connectivity imposes constraints on the localization of the dissociated (charged) monomers that affect the local electric potential. As a result, the mean bare charge along a weak polyelectrolyte can vary depending on the proximity to topological features (e.g. presence of crosslinks or dangling ends). Using reaction‐ensemble Monte‐Carlo simulations we calculate the dissociation inhomogeneities for a few selected PE configurations, linear, rod‐like, flexible four‐arm star, and a star with stiff arms. An ensemble preaverage is used to obtain the annealed bare charge profile for these different polymer configurations. Using molecular dynamics simulations within a Lattice‐Boltzman fluid, we investigate how the electrophoretic mobility is affected by the bare charge inhomogeneities arising from the annealed weak polyelectrolytes. Surprisingly, the mobility obtained for the situations corresponding to the predicted charge profile for annealed weak polyelectrolytes are not significantly different than the mobility obtained when all the monomers have an identical charge (under the constraint that the total polyelectrolyte bare charge is the same). This is also true for the stiff rod‐like variants where conformational changes induced from the localization of the monomer charges are negligible. In salty solutions, we find that counterions are affected by the electric potential modulations induced by the topological features. Since the counterions crowd in regions where the electric potential caused by the dissociated monomers is highest, they wash‐out the bare charge inhomogeneities and contribute to a more uniform effective backbone charge.
Combining expert‐adjusted forecasts
Authors: van Dijk Dick , Franses Philip Hans 
Published: January 2019

AbstractIt is well known that a combination of model‐based forecasts can improve upon each of the individual constituent forecasts. Most forecasts available in practice are, however, not purely based on econometric models but entail adjustments, where experts with domain‐specific knowledge modify the original model forecasts. There is much evidence that expert‐adjusted forecasts do not necessarily improve the pure model‐based forecasts. In this paper we show, however, that combined expert‐adjusted model forecasts can improve on combined model forecasts, in the case when the individual expert‐adjusted forecasts are not better than their associated model‐based forecasts. We discuss various implications of this finding.
Sentiment indices and their forecasting ability
Authors: Mascio David A. , Fabozzi Frank J. 
Published: January 2019

AbstractThe success of any timing strategy depends on the accuracy of market forecasts. In this paper, we test five indices to forecast the 1‐month‐ahead performance of the S&P 500 Index. These indices reflect investor sentiment, current business conditions, economic policy uncertainty, and market dislocation information. Each model is used in a logistic regression analysis to predict the 1‐month‐ahead market direction, and the forecasts are used to adjust the portfolio's beta. Beta optimization refers to a strategy designed to create a portfolio beta of 1.0 when the market is expected to go up, and a beta of −1.0 when a bear market is expected. Successful application of this strategy generates returns that are consistent with a call option or an option straddle position; that is, positive returns are generated in both up and down markets. Analysis reveals that the models' forecasts have discriminatory power in identifying substantial market movements, particularly during the bursting of the tech bubble and the financial crisis. Four of the five forecast models tested outperform the benchmark index.
Identifying an analytical tool to assess the readiness of aid information and communication technology projects
Authors: Kaba Bangaly 
Published: January 2019

AbstractIt has been established that information and communication technologies (ICTs) empower the informal sector. However, according to a study, a number of barriers such as affordability, availability, and access lead to the informal sector being a low‐tech environment. Thus, aid agencies and African governments have made notable efforts to promote the spread and use of ICT in Africa in order to support sustainable development in African countries. These initiatives are managed on a project basis. Unfortunately, the success rate of development aid projects is relatively low. Several explanations have been given for these failures. We performed a conceptual analysis where we identify the important drivers that should be considered when assessing the likelihood of success of these projects, namely, project readiness, before such projects are implemented. The analytical framework that is proposed will contribute to the success of ICT projects.
The pathogenesis of tuberculous meningitis
Authors: Davis Angharad Grace , Rohlwink Ursula Karin , Proust Alizé , Figaji Anthony A , Wilkinson Robert J 
Published: January 2019

Abstract
Tuberculosis (TB) remains a leading cause of death globally. Dissemination of TB to the brain results in the most severe form of extrapulmonary TB, tuberculous meningitis (TBM), which represents a medical emergency associated with high rates of mortality and disability. Via various mechanisms the Mycobacterium tuberculosis (M.tb) bacillus disseminates from the primary site of infection and overcomes protective barriers to enter the CNS. There it induces an inflammatory response involving both the peripheral and resident immune cells, which initiates a cascade of pathologic mechanisms that may either contain the disease or result in significant brain injury. Here we review the steps from primary infection to cerebral disease, factors that contribute to the virulence of the organism and the vulnerability of the host and discuss the immune response and the clinical manifestations arising. Priorities for future research directions are suggested.
Review on how morbidity and mortality caused by tuberculous meningitis is mediated by a dysregulated immune response.
Megakaryocytes as immune cells
Authors: Cunin Pierre , Nigrovic Peter A 
Published: January 2019

Abstract
Platelets play well-recognized roles in inflammation, but their cell of origin—the megakaryocyte—is not typically considered an immune lineage. Megakaryocytes are large polyploid cells most commonly identified in bone marrow. Egress via sinusoids enables migration to the pulmonary capillary bed, where elaboration of platelets can continue. Beyond receptors involved in hemostasis and thrombosis, megakaryocytes express receptors that confer immune sensing capacity, including TLRs and Fc-γ receptors. They control the proliferation of hematopoietic cells, facilitate neutrophil egress from marrow, possess the capacity to cross-present antigen, and can promote systemic inflammation through microparticles rich in IL-1. Megakaryocytes internalize other hematopoietic lineages, especially neutrophils, in an intriguing cell-in-cell interaction termed emperipolesis. Together, these observations implicate megakaryocytes as direct participants in inflammation and immunity.
Effects of dietary fatty acid content on humeral cartilage and bone structure in a mouse model of diet‐induced obesity
Authors: Votava Lauren , Schwartz Andrea G. , Harasymowicz Natalia S. , Wu Chia‐Lung , Guilak Farshid 
Published: January 2019

ABSTRACTObesity is a primary risk factor for osteoarthritis (OA), and previous studies have shown that dietary content may play an important role in the pathogenesis of cartilage and bone in knee OA. Several previous studies have shown that the ratio of ω‐3 polyunsaturated fatty acids (PUFAs), ω‐6 PUFAs, and saturated fatty acids can significantly influence bone structure and OA progression. However, the influence of obesity or dietary fatty acid content on shoulder OA is not well understood. The goal of this study was to investigate the role of dietary fatty acid content on bone and cartilage structure in the mouse shoulder in a model of diet‐induced obesity. For 24 weeks, mice were fed control or high‐fat diets supplemented with ω‐3 PUFAs, ω‐6 PUFAs, or saturated fatty acids. The humeral heads were analyzed for bone morphometry and mineral density by microCT. Cartilage structure and joint synovitis were determined by histological grading, and microscale mechanical properties of the cartilage extracellular and pericellular matrices were quantified using atomic force microscopy. Diet‐induced obesity significantly altered bone morphology and mineral density in a manner that was dependent on dietary free fatty acid content. In general, high‐fat diet groups showed decreased bone quality, with the ω‐3 diet being partially protective. Cartilage mechanical properties and OA scores showed no changes with obesity or diet. These findings are consistent with clinical literature showing little if any relationship between obesity and shoulder OA (unlike knee OA), but suggest that diet‐induced obesity may influence other joint tissues. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Enhancement of the chondrogenic differentiation of mesenchymal stem cells and cartilage repair by ghrelin
Authors: Fan Litong , Chen Jiaqing , Tao Yanmeng , Heng Boon Chin , Yu Jiakuo , Yang Zheng , Ge Zigang 
Published: January 2019

ABSTRACTTransforming growth factor beta (TGF‐β) is commonly utilized in chondrogenic differentiation protocols, but this often results in incomplete maturation of the derived chondrocytes. Gene expression analysis, quantitation of sulfated glycosaminoglycan and collagen, and histological staining were performed to assess the effects of ghrelin. The signaling pathways involved were investigated with inhibitors or targeted by shRNAs. Joint cavity delivery of TGF‐β with or without ghrelin, within a rat cartilage defect model was performed to evaluate the in vivo effects of ghrelin. Ghrelin dramatically enhanced gene expression levels of SOX9, ACAN, and COL II and resulted in increased synthesis of sulfated glycosaminoglycan (sGAG) and collagen in vitro. Combined treatment with TGF‐β and ghrelin synergistically enhanced the phosphorylation of ERK1/2 and DMNT3A, which accounted for increased expression of chondrogenic genes. Delivery of ghrelin in combination with TGF‐β after MSC implantation within a rat osteochondral defect model significantly enhanced de novo cartilage regeneration, as compared to delivery with TGF‐β alone. In conclusion, ghrelin could significantly enhance MSC chondrogenic differentiation in vitro and can also enhance cartilage regeneration in vivo when used in combination with TGF‐β. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1387–1397, 2019.
Evidence for regional‐scale controls on eelgrass (Zostera marina) and mesograzer community structure in upwelling‐influenced estuaries
Authors: Hayduk Jennifer L. , Hacker Sally D. , Henderson Jeremy S. , Tomas Fiona 
Published: January 2019

AbstractCommunity structure and function in ecosystems are dependent on top‐down and bottom‐up factors, which vary across local, regional, and temporal scales. In estuaries of the U.S. Pacific Northwest coast, eelgrass (Zostera marina) ecosystems are exposed to latitudinally varying oceanographic inputs in the form of ocean upwelling. Previous research suggests that ocean upwelling is critical to eelgrass and ulvoid macroalgae abundance, but the degree to which secondary producers are controlled by processes at regional vs. local scales is unknown. Here, we consider the relationships among primary producers (eelgrass, ulvoid macroalgae, and epiphytic microalgae), epifaunal mesograzers, and mesopredator fish within and across three Oregon, U.S.A., estuaries during a spring–summer season to examine the role of multiple scales in structuring these communities. Our objectives were to determine the relative importance of local and regional scales in organizing eelgrass communities and the potential of regional oceanography and trophic interactions in regulating patterns of primary producers in this system. We found that regional and seasonal patterns strongly influenced eelgrass community structure, providing support for the hypothesis that regional bottom‐up forcing predominantly controls these assemblages. Additionally, local effects were important to the patterns of primary producers, mesograzers, and mesopredator fish at specific sites, suggesting limited top–down control. Regarding management and conservation, the implications of our results are that in these highly productive systems, the potential for consumers to moderate the effects of eutrophication may be limited.
Benthic microalgae offset the sediment carbon dioxide emission in subtropical mangrove in cold seasons
Authors: Chen Shunyang , Chmura Gail L. , Wang Yu , Yu Dan , Ou Danyun , Chen Bin , Ye Yong , Chen Guangcheng 
Published: January 2019

AbstractOur study examined the relationship of microphytobenthos to greenhouse gas fluxes from sediments of a subtropical mangrove forest and adjacent mudflat in the Jiulong River Estuary, South China. The relationship between chlorophyll a concentration at the sediment surface and diatom density confirmed that these microalgae were the important component of the microphytobenthos, which produced an observable biofilm in cold seasons (winter and spring) on both the mangrove and mudflat sediment surfaces. Fluxes of methane and nitrous oxide were not affected by the microalgae film and were similar between the mangrove and mudflat. However, benthic microalgae affected the sediment to atmosphere carbon dioxide (CO2) flux, and the effect was temporally variable with the seasonal change in microalgae abundance. In the cold seasons, the mangrove sediment was a CO2 sink under light chambers but a source under dark chambers. In summer, when there was no visible microalgae film at the sediment surface, the intertidal sediments had CO2 emissions and comparable fluxes between the two chambers. The negative daily CO2 fluxes of the film‐covered sediment (as the average of the dark and light fluxes) and positive flux of the sediment without visible biofilm indicated that the occurrence of microalgae film converted the mangrove sediment from a CO2 source to a sink and that the photosynthesis of the microalgae film offset the sediment respiration during the cold seasons in this study. We also found similar effects of microalgae on CO2 fluxes on the nonvegetated mudflat.
One‐Step Labeling of Collagen Hydrogels with Polydopamine and Manganese Porphyrin for Non‐Invasive Scaffold Tracking on Magnetic Resonance Imaging
Authors: Szulc Daniel Andrzej , Cheng Hai‐Ling Margaret 
Published: January 2019

AbstractBiomaterial scaffolds are the cornerstone to supporting 3D tissue growth. Optimized scaffold design is critical to successful regeneration, and this optimization requires accurate knowledge of the scaffold's interaction with living tissue in the dynamic in vivo milieu. Unfortunately, non‐invasive methods that can probe scaffolds in the intact living subject are largely underexplored, with imaging‐based assessment relying on either imaging cells seeded on the scaffold or imaging scaffolds that have been chemically altered. In this work, the authors develop a broadly applicable magnetic resonance imaging (MRI) method to image scaffolds directly. A positive‐contrast “bright” manganese porphyrin (MnP) agent for labeling scaffolds is used to achieve high sensitivity and specificity, and polydopamine, a biologically derived universal adhesive, is employed for adhering the MnP. The technique was optimized in vitro on a prototypic collagen gel, and in vivo assessment was performed in rats. The results demonstrate superior in vivo scaffold visualization and the potential for quantitative tracking of degradation over time. Designed with ease of synthesis in mind and general applicability for the continuing expansion of available biomaterials, the proposed method will allow tissue engineers to assess and fine‐tune the in vivo behavior of their scaffolds for optimal regeneration.