TLS-bridged co-prediction of tree-level multifarious stem structure variables from worldview-2 panchromatic imagery: a case study of the boreal forest

In forest ecosystem studies, tree stem structure variables (SSVs) proved to be an essential kind of parameters, and now simultaneously deriving SSVs of as many kinds as possible at large scales is preferred for enhancing the frontier studies on marcoecosystem ecology and global carbon cycle. For this newly emerging task, satellite imagery such as WorldView-2 panchromatic images (WPIs) is used as a potential solution for co-prediction of tree-level multifarious SSVs, with static terrestrial laser scanning (TLS) assumed as a ‘bridge’. The specific operation is to pursue the allometric relationships between TLS-derived SSVs and WPI-derived feature parameters, and regression analyses with one or multiple explanatory variables are applied to deduce the prediction models (termed as Model1s and Model2s). In the case of Picea abies, Pinus sylvestris, Populus tremul and Quercus robur in a boreal forest, tests showed that Model1s and Model2s for different tree species can be derived (e.g. the maximum R2 = 0.574 for Q. robur). Overall, this study basically validated the algorithm proposed for co-prediction of multifarious SSVs, and the contribution is equivalent to developing a viable solution for SSV-estimation upscaling, which is useful for large-scale investigations of forest understory, macroecosystem ecology, global vegetation dynamics and global carbon cycle.This work was financially supported in part by the National Natural Science Foundation of China [grant numbers 41471281 and 31670718] and in part by the SRF for ROCS, SEM, China. (41471281 - National Natural Science Foundation of China; 31670718 - National Natural Science Foundation of China; SRF for ROCS, SEM, China)http://www-tandfonline-com.ezproxy.bu.edu/doi/abs/10.1080/17538947.2016.1247473?journalCode=tjde20Published versio

Sub-wavelength imaging with a left-handed material flat lens

We study numerically, by means of the pseudospectral time-domain method, the unique features of imaging by a flat lens made of a left-handed metamaterial that possesses the property of negative refraction. We confirm the earlier finding that a left-handed flat lens can provide near-perfect imaging of a point source and a pair of point sources with clear evidence of the sub-wavelength resolution. We illustrate the limitation of the resolution in the time-integrated image due to the presence of surface waves.Comment: 4 pages, RevTeX, 6 figures; added references and some discussio

Neuronal-Derived Extracellular Vesicles are Enriched in the Brain and Serum of HIV-1 Transgenic Rats

Despite the efficacy of combination antiretroviral therapy (ART) in controlling human immunodeficiency virus (HIV-1) replication, cytotoxic viral proteins such as HIV-1 transactivator of transcription (Tat) persist in tissues such as the brain. Although HIV-1 does not infect neuronal cells, it is susceptible to viral Tat protein-mediated toxicity, leading to neuroinflammation that underlies HIV-associated neurocognitive disorders (HAND). Given the role of extracellular vesicles (EVs) in both cellular homoeostasis and under pathological conditions, we sought to investigate the alterations in the quantity of neuronal-derived EVs in the brain–as defined by the presence of cell adhesion molecule L1 (L1CAM) and to evaluate the presence of L1CAM+ EVs in the peripheral circulation of HIV-1 transgenic (HIV-1 Tg) rats. The primary goal of this study was to investigate the effect of long-term exposure of HIV-1 viral proteins on the release of neuronal EVs in the brain and their transfer in the systemic compartment. Brain and serum EVs were isolated from both wild type and HIV-1 Tg rats using differential ultracentrifugation with further purification using the Optiprep gradient method. The subpopulation of neuronal EVs was further enriched using immunoprecipitation. The current findings demonstrated increased presence of L1CAM+ neuronal-derived EVs both in the brain and serum of HIV-1 Tg rats. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of The International Society for Extracellular Vesicles

Sharing luxury possessions in the age of digital experience economy: Consumption type and psychological entitlement

With the advent of the digital experience economy, contemporary luxury brands have embraced social media as an important channel for improving brand perceptions and developing customer relationships. This is because encouraging consumers to share luxury purchases on social media offers a strategic value for luxury brands. The present research investigates the conditions under which consumers are more likely to share luxury (vs. nonluxury) purchases on social media. Across two experiments, we establish that luxury (vs. non-luxury) purchases are shared more when they are associated with material (vs. experiential) consumption, and among consumers with a high (vs. low) sense of entitlement. These findings make several theoretical and managerial contributions, providing avenues for future research on what consumers do with luxury brands on social media

Astrocyte EV-Induced lincRNA-Cox2 Regulates Microglial Phagocytosis: Implications for Morphine-Mediated Neurodegeneration

Impairment of microglial functions, such as phagocytosis and/ or dysregulation of immune responses, has been implicated as an underlying factor involved in the pathogenesis of various neurodegenerative disorders. Our previous studies have demonstrated that long intergenic noncoding RNA (lincRNA)-Cox2 expression is influenced by nuclear factor kB (NF-kB) signaling and serves as a coactivator of transcriptional factors to regulate the expression of a vast array of immune- related genes in microglia. Extracellular vesicles (EVs) have been recognized as primary facilitators of cell-to-cell communication and cellular regulation. Herein, we show that EVs derived from astrocytes exposed to morphine can be taken up by microglial endosomes, leading, in turn, to activation of Toll-like receptor 7 (TLR7) with a subsequent upregulation of lincRNA-Cox2 expression, ultimately resulting in impaired microglial phagocytosis. This was further validated in vivo, wherein inhibition of microglial phagocytic activity was also observed in brain slices isolated from morphine-administrated mice compared with control mice. Additionally, we also showed that intranasal delivery of EVs containing lincRNA-Cox2 siRNA (small interfering RNA) was able to restore microglial phagocytic activity in mice administered morphine. These findings have ramifications for the development of EV-loaded RNA-based therapeutics for the treatment of various disorders involving functional impairment of microglia

Quantum systems in weak gravitational fields

Fully covariant wave equations predict the existence of a class of inertial-gravitational effects that can be tested experimentally. In these equations inertia and gravity appear as external classical fields, but, by conforming to general relativity, provide very valuable information on how Einstein's views carry through in the world of the quantum.Comment: 22 pages. To be published in Proceedings of the 17th Course of the International School of Cosmology and Gravitation "Advances in the interplay between quantum and gravity physics" edited by V. De Sabbata and A. Zheltukhin, Kluwer Academic Publishers, Dordrech

Wolf Creek Cold Regions Model Set-up, Parameterisation and Modelling Summary

Non-Peer ReviewedWolf Creek Research Basin is in the Upper Yukon River Basin near Whitehorse, Yukon and is representative of headwaters in the northern Coast Mountains. It was established in 1993 to better develop northern hydrological models, and related hydrological process, ecosystem and climate science. Yukon Environment maintains Wolf Creek hydrometeorological and hydrometric stations and conducts regular snow surveys in the basin. A number of hydrological models have been tested on Wolf Creek and all have had great difficulty in simulating the cold regions hydrological processes that dominate its streamflow response to snowmelt and rainfall events. Developments in understanding hydrological processes and their interaction with terrestrial ecosystems and climate at Wolf Creek have lead to the development of the Cold Regions Hydrological Model (CRHM) by a consortium of scientists led by the University of Saskatchewan and Environment Canada. CRHM comprehensively incorporates the blowing snow, intercepted snow, sublimation, melt energetics, infiltration to frozen soils, organic terrain runoff and other cold regions hydrological phenomenon and discretizes the catchment on a hydrological response unit basis for applying water and energy balance calculations. The model is intended for prediction of ungauged basins with parameter selection from physically measurable properties of the river basin or regional transference of calibrated values. In Russia, a long tradition of cold regions hydrological research has led to the development of the Hydrograph model by the State Hydrological Institute, St. Petersburg. The Hydrograph model contains several promising innovations regarding the formation and routing of runoff, discretizes the basin using hydrological response units and addresses some (but not all) cold regions hydrological processes. Hydrograph parameter selection is made from both physically measured properties and those that are calibrated, but the calibrations can be easily regionalized. Test simulations of runoff processes using CRHM and Hydrograph for Wolf Creek Research Basin was undertaken using data archives that had been assembled and cleaned up in a related project by the University of Saskatchewan. The test simulations are a demonstration of model capabilities and a way to gain familiarity with the basin, its characteristics and data and to better compare model features. Data available included a GIS database of basin characteristics (topography and vegetation distribution) and the hydrometeorological and hydrometric observational dataset from Yukon Environment. The sub-surface hydrology presented a formidable unknown in parameterising the model. Hydrograph performed well in initial simulations of the basin hydrograph for multi-year runs. Several issues with observational data quality created substantial uncertainty in evaluating the model runs

Genome-wide profiling of forum domains in Drosophila melanogaster

Forum domains are stretches of chromosomal DNA that are excised from eukaryotic chromosomes during their spontaneous non-random fragmentation. Most forum domains are 50–200 kb in length. We mapped forum domain termini using FISH on polytene chromosomes and we performed genome-wide mapping using a Drosophila melanogaster genomic tiling microarray consisting of overlapping 3 kb fragments. We found that forum termini very often correspond to regions of intercalary heterochromatin and regions of late replication in polytene chromosomes. We found that forum domains contain clusters of several or many genes. The largest forum domains correspond to the main clusters of homeotic genes inside BX-C and ANTP-C, cluster of histone genes and clusters of piRNAs. PRE/TRE and transcription factor binding sites often reside inside domains and do not overlap with forum domain termini. We also found that about 20% of forum domain termini correspond to small chromosomal regions where Ago1, Ago2, small RNAs and repressive chromatin structures are detected. Our results indicate that forum domains correspond to big multi-gene chromosomal units, some of which could be coordinately expressed. The data on the global mapping of forum domains revealed a strong correlation between fragmentation sites in chromosomes, particular sets of mobile elements and regions of intercalary heterochromatin