1,757 research outputs found

    Supplementary publications presented by Mr J. M. Stagg for the degree of D.Sc.

    Get PDF
    Volume 01 | BRITISH POLAR YEAR EXPEDITION FORT RAE, N.W. CANADA 1932-33 VOLUME I | DISCUSSION OF RESULTSVolume 02 | BRITISH POLAR YEAR EXPEDITION FORT RAE, N.W. CANADA 1932-33 VOLUME II | TABLESVolume 03 | 01. Some General Characteristics of Aurora at Fort Rae N.W. Canada 1932-33 | 02. NUMERICAL CHARACTER FIGURES OF MAGNETIC DISTURBANCE IN RELATION TO GEOMAGNETIC LATITUDE | 03. .Aspects of the Current System Producing Magnetic Disturbance | 04. The Diurnal Variation of Magnetic Disturbance in High Latitudes | 05. On the Variability of the Quiet -Day Diurnal Magnetic Variation at Eskdalemuir and Greenwich. By S. CHAPMAN, F.R.S., AND J. M. STAGG. | 06. On the Variability of the Quiet -Day Diurnal Magnetic Variation. Part II. BY S. CHAPMAN, F.R.S., AND J. M. STAGG. | 07. On the Variability of the Quiet -Day Diurnal Magnetic Variation. Part II. BY S. CHAPMAN, F.R.S., AND J. M. STAGG. | 08. Hourly Character Figures of Magnetic Disturbance at Kew Observatory, Richmond 1913-23 | 09. The Time Interval BETWEEN Magnetic Disturbance AND Associated Sunspot Changes | 10. THE ABSOLUTE DAILY RANGE OF MAGNETIC DECLINATION AT KEW OBSERVATORY, RICHMOND, 1901 to 1910 | 11. On Magnetic Fluctuations and Sunspot Frequency: A Discussion based primarily on the daily ranges of Declination as recorded at Kew Observatory, Richmond, during the 67 years 1858-1924 | 12. The 27-Day Recurrence Interval in Magnetic Disturbance: An Examination made with the aid of hourly Character Figures

    Point-to-Multipoint Communication Enablers for the Fifth Generation of Wireless Systems

    Full text link
    (c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.[EN] 3GPP has enhanced the point-to-multipoint (PTM) communication capabilities of 4G LTE in all releases since the adoption of eMBMS in Release-9. Recent enhancements cover not only television services, but also critical machine-type and vehicular communications, following the backward-compatibility design philosophy of LTE. This article discusses the opportunity in the design and standardization of 5G to break with the existing paradigm for PTM transmissions in 4G LTE, where broadcast PTM transmissions were initially conceived as an add-on and pre-positioned service. 5G brings the opportunity to incorporate PTM capabilities as built-in delivery features from the outset, integrating point-to-point and PTM modes under one common framework and enabling dynamic use of PTM to maximize network and spectrum efficiency. This approach will open the door to completely new levels of network management and delivery cost efficiency. The article also discusses the implications of PTM for network slicing to customize and optimize network resources on a common 5G infrastructure to accommodate different use cases and services taking into account user densityThis work was supported in part by the European Commission under the 5G-PPP project Broadcast and Multicast Communication Enablers for the Fifth-(H2020-ICT-2016-2 call, grant number 761498). The views expressed in this contribution are those of the authors and do not necessarily represent the project.Generation of Wireless Systems 5G-XcastGomez-Barquero, D.; Navratil, D.; Appleby, S.; Stagg, M. (2018). Point-to-Multipoint Communication Enablers for the Fifth Generation of Wireless Systems. IEEE Communications Standards Magazine. 2(1):53-59. https://doi.org/10.1109/MCOMSTD.2018.170006953592

    Shipping and the Spread of Infectious Salmon Anemia in Scottish Aquaculture

    Get PDF
    Long-distance transport of pathogens plays a critical role in the emergence of novel diseases. Shipping is a major contributor to such transport, and the role of ships in spreading disease has been recognized for centuries. However, statistical confirmation of pathogen spread by shipping is usually impractical. We present evidence of invasive spread of infectious salmon anemia in the salmon farms of Scotland and demonstrate a link between vessel visits and farm contamination. The link is associated with vessels moving fish between sites and transporting harvest, but not with vessels delivering food or involved in other work

    The Distribution of ORCUTTIA CALIFORNICA (Poaceae) in the Vernal Pools of the Santa Rosa Plateau, Riverside County, California

    Get PDF
    Ecological studies were conducted on the rare annual grass Orcuttia californica (Vasey), an endemic to California, from April to September, 1976 in 11 vernal pools located on the Santa Rosa Plateau in Riverside County. To help determine why Orcutt grass occurs in only 6 of the 11 pools and more specifically why it only occurs in patches within a given pool, biweekly measurements of frequency, density and phenology were taken within each of a total of 28 circular plots (r = 10 meters) in 5 pools. This data was related to concurrent biweekly measurements of soil moisture, soil texture and microrelief of each plot, area and order of desiccation of each pool. Frequency and density show no correlation to soil moisture, soil texture, and area. There is, however, a positive correlation between occurrence of the study species and the (1) order in which the pools become desiccated; and (2) average depth of plot. This is probably related to the germination requirement of the seeds having to be submerged for a minimum amount of time. Also under different soil moisture conditions there seem to be differences in the time sequences of the phenological events

    The structures of natively assembled clathrin-coated vesicles

    Get PDF
    Clathrin-coated vesicles mediate trafficking of proteins and nutrients in the cell and between organelles. Proteins included in the clathrin-coated vesicles (CCVs) category include clathrin heavy chain (CHC), clathrin light chain (CLC), and a variety of adaptor protein complexes. Much is known about the structures of the individual CCV components, but data are lacking about the structures of the fully assembled complexes together with membrane and in complex with cargo. Here, we determined the structures of natively assembled CCVs in a variety of geometries. We show that the adaptor β2 appendages crosslink adjacent CHC β-propellers and that the appendage densities are enriched in CCV hexagonal faces. We resolve how adaptor protein 2 and other associated factors in hexagonal faces form an assembly hub with an extensive web of interactions between neighboring β-propellers and propose a structural model that explains how adaptor binding can direct the formation of pentagonal and hexagonal faces

    Integrating Remote Sensing with Ground-based Observations to Quantify the Effects of an Extreme Freeze Event on Black Mangroves (Avicennia germinans) at the Landscape Scale

    Get PDF
    Climate change is altering the frequency and intensity of extreme weather events. Quantifying ecosystem responses to extreme events at the landscape scale is critical for understanding and responding to climate-driven change but is constrained by limited data availability. Here, we integrated remote sensing with ground-based observations to quantify landscape-scale vegetation damage from an extreme climatic event. We used ground- and satellite-based black mangrove (Avicennia germinans) leaf damage data from the northern Gulf of Mexico (USA and Mexico) to examine the effects of an extreme freeze in a region where black mangroves are expanding their range. The February 2021 event produced coastal temperatures as low as − 10 °C in some areas, exceeding thresholds for A. germinans damage and mortality. We used Sentinel-2 surface reflectance data to assess vegetation greenness before and after the freeze, along with ground-based observations of A. germinans leaf damage. Our results show a negative, nonlinear threshold relationship between A. germinans leaf damage and minimum temperature, with a temperature threshold for leaf damage near − 6 °C. Satellite-based analyses indicate that, at the landscape scale, damage was particularly severe along the central Texas coast, where the freeze event affected \u3e 2000 ha of A. germinans-dominated coastal wetlands. Our analyses highlight the value of pairing remotely sensed data with regional, ground-based observations for quantifying and extrapolating the effects of extreme freeze events on mangroves and other tropical, cold-sensitive plants. The results also demonstrate how extreme freeze events govern the expansion and contraction of mangroves near northern range limits in North America

    Hunting for answers: Linking lectures with the real world using a mobile treasure hunt app

    Get PDF
    Plants underpin our society providing food, fuel, medicines, clean air and water, positive mental health, and are central to biodiversity conservation. Despite this importance and an increasing need for people with plant-identification skills, many societies are becoming increasingly ignorant to the species with which they interact. To benefit both our undergraduates and the society they will enter, we applied mobile technology to improve plant identification and appreciation , while providing opportunities to practice transferable team work and verbal communication skills. Encouraging 'plant vision' will improve conservation efforts while increasing personal connections with green spaces, leading to mental health improvements for society. Summary • Despite the importance of plants to human civilization, many societies are becoming increasingly ignorant to the plants that inhabit their surrounding environment. A phenomenon known as 'plant blindness'. To address plant blindness in undergraduate students we designed an outdoor activity using a mobile phone app. Our aims were to identify the level of 'plant blindness' in our students; investigate engagement with the app and activity ; determine if we can raise awareness of links between lecture content and real world scenarios; and assess the student experience as a result of the activity in large classes. • The app chosen was ActionBound. Students were asked to find and photograph local examples of four plant families, along with identifying physiological benefits of features covered in lectures. Two different first year classes were exposed to this activity-Plant Science and Life on Earth. • The Plant Science students (60% success rate for three families; 55 students) were less plant blind than Life on Earth students (less than 44% success rate in any of the four families; 200 students). Students engaged well with the activity with all groups submitting sensible attempts at the responses. Most students reported that the activity increased links to lecture material and all but one student reported positive experiences. • Our students found the treasure hunt learning environment is a fun way to engage with the plant topics covered in lectures. In future iterations, we will more explicitly explain the links to potential careers and will address some of the logistical challenges faced in this first cohort. K E Y W O R D S collaborative learning, fun learning, inclusivity, large classes, mobile learning, plant blindness, situational learning, treasure hun

    The role of ectonucleotidases CD39 and CD73 and adenosine signaling in solid organ transplantation

    Get PDF
    Extracellular adenosine is a potent immunomodulatory molecule that accumulates in states of inflammation. Nucleotides such as adenosine triphosphate and adenosine diphosphate are release from injured and necrotic cells and hydrolyzed to adenosine monophosphate and adenosine by the concerted action of the ectonucleotidases CD39 and CD73. Accumulating evidence suggest that purinergic signaling is involved in the inflammatory response that accompanies acute rejection and chronic allograft dysfunction. Modification of the purinergic pathway has been shown to alter graft survival in a number of solid organ transplant models and the response to ischemia–reperfusion injury (IRI). Furthermore, the purinergic pathway is intrinsically involved in B and T cell biology and function. Although T cells have traditionally been considered the orchestrators of acute allograft rejection, a role for B cells in chronic allograft loss is being increasingly appreciated. This review focuses on the role of the ectonucleotidases CD39 and CD73 and adenosine signaling in solid organ transplantation including the effects on IRI and T and B cell biology

    Processes Contributing to Resilience of Coastal Wetlands to Sea-Level Rise

    Get PDF
    The objectives of this study were to identify processes that contribute to resilience of coastal wetlands subject to rising sea levels and to determine whether the relative contribution of these processes varies across different wetland community types. We assessed the resilience of wetlands to sea-level rise along a transitional gradient from tidal freshwater forested wetland (TFFW) to marsh by measuring processes controlling wetland elevation. We found that, over 5 years of measurement, TFFWs were resilient, although some marginally, and oligohaline marshes exhibited robust resilience to sea-level rise. We identified fundamental differences in how resilience is maintained across wetland community types, which have important implications for management activities that aim to restore or conserve resilient systems. We showed that the relative importance of surface and subsurface processes in controlling wetland surface elevation change differed between TFFWs and oligohaline marshes. The marshes had significantly higher rates of surface accretion than the TFFWs, and in the marshes, surface accretion was the primary contributor to elevation change. In contrast, elevation change in TFFWs was more heavily influenced by subsurface processes, such as root zone expansion or compaction, which played an important role in determining resilience of TFFWs to rising sea level. When root zone contributions were removed statistically from comparisons between relative sea-level rise and surface elevation change, sites that previously had elevation rate deficits showed a surplus. Therefore, assessments of wetland resilience that do not include subsurface processes will likely misjudge vulnerability to sea-level rise

    Processes Contributing to Resilience of Coastal Wetlands to Sea-Level Rise

    Get PDF
    The objectives of this study were to identify processes that contribute to resilience of coastal wetlands subject to rising sea levels and to determine whether the relative contribution of these processes varies across different wetland community types. We assessed the resilience of wetlands to sea-level rise along a transitional gradient from tidal freshwater forested wetland (TFFW) to marsh by measuring processes controlling wetland elevation. We found that, over 5 years of measurement, TFFWs were resilient, although some marginally, and oligohaline marshes exhibited robust resilience to sea-level rise. We identified fundamental differences in how resilience is maintained across wetland community types, which have important implications for management activities that aim to restore or conserve resilient systems. We showed that the relative importance of surface and subsurface processes in controlling wetland surface elevation change differed between TFFWs and oligohaline marshes. The marshes had significantly higher rates of surface accretion than the TFFWs, and in the marshes, surface accretion was the primary contributor to elevation change. In contrast, elevation change in TFFWs was more heavily influenced by subsurface processes, such as root zone expansion or compaction, which played an important role in determining resilience of TFFWs to rising sea level. When root zone contributions were removed statistically from comparisons between relative sea-level rise and surface elevation change, sites that previously had elevation rate deficits showed a surplus. Therefore, assessments of wetland resilience that do not include subsurface processes will likely misjudge vulnerability to sea-level rise
    • …
    corecore