bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal variations in the 14C Content of Tree Rings: Influences on Radiocarbon Calibration and Single-Year Curve Construction
Authors: McDonald Liam , Chivall David , Miles Daniel , Bronk Ramsey Christopher 
Published: July 2018

AbstractTo examine the implications of seasonality for the construction of a single-year calibration curve we obtained separate dates on earlywood and latewood fractions of tree rings originating from England and dendrochronologically dated between AD 1352 and AD 1442. These demonstrated that an average difference of 26±15 yr exists between earlywood and latewood and that this difference can be as high as 33±19 yr during periods of high radiocarbon (14C) production. It is argued that this difference is due to both changes in atmospheric 14C and the incorporation of stored carbohydrates into earlywood. Based on this, it was possible to separate an atmospheric and physiological contribution to this difference. Our modeling indicates that storage can produce a difference of up to 10 years between earlywood and latewood. This suggests that full-year tree rings from deciduous trees may be less appropriate for the construction of a single-year calibration curve and that specific atmospheric events can be more easily detected by measuring only latewood.
Global burden of hearing impairment and ear disease
Authors: Graydon K , Waterworth C , Miller H , Gunasekera H 
Published: July 2018

AbstractBackgroundHearing loss can present at birth or be acquired as a result of illness, middle-ear disease, injury, age, overuse of certain medications, and/or induced by exposure to damaging noise levels. There are serious short-term consequences for people living with hearing impairment, including the effects on language acquisition, education, employment and overall wellbeing. There are also complex long-term implications.ObjectivesThis review aimed to present some of the leading causes of ear disease and hearing loss globally, and to identify their impact at both an individual and societal level.
Assembly and division of the South and South-East Asian flora in relation to tectonics and climate change
Authors: Morley Robert J. 
Published: July 2018

Abstract:The main phases of plant dispersal into, and out of the South-East Asian region are discussed in relation to plate tectonics and changing climates. The South-East Asian area was a backwater of angiosperm evolution until the collision of the Indian Plate with Asia during the early Cenozoic. The Late Cretaceous remains poorly understood, but the Paleocene topography was mountainous, and the climate was probably seasonally dry, with the result that frost-tolerant conifers were common in upland areas and a low-diversity East Asian aspect flora occurred at low altitudes. India's drift into the perhumid low latitudes during the Eocene brought opportunities for the dispersal into South-East Asia of diverse groups of megathermal angiosperms which originated in West Gondwana. They successfully dispersed and became established across the South-East Asian region, initially carried by wind or birds, beginning at about 49 Ma, and with a terrestrial connection after about 41 Ma. Many Paleocene lineages probably went extinct, but a few dispersed in the opposite direction into India. The Oligocene was a time of seasonally dry climates except along the eastern and southern seaboard of Sundaland, but with the collision of the Australian Plate with Sunda at the end of the Oligocene widespread perhumid conditions became established across the region. The uplift of the Himalaya, coinciding with the middle Miocene thermal maximum, created opportunities for South-East Asian evergreen taxa to disperse into north India, and then with the late Miocene strengthening of the Indian monsoon, seasonally dry conditions expanded across India and Indochina, resulting eventually in the disappearance of closed forest over much of the Indian peninsula. This drying affected Sunda, but it is thought unlikely that a ‘savanna’ corridor was present across Sunda during the Pleistocene. Some dispersals from Australasia occurred following its collision with Sunda and following the uplift of New Guinea and the islands of Wallacea, Gondwanan montane taxa also found their way into the region. Phases of uplift across the Sunda region created opportunities for allopatric speciation and further dispersal opportunities. There is abundant evidence to suggest that the Pleistocene refuge theory applies to the South-East Asian region.
Temporal dynamics in the effectiveness of seed dispersal by birds visiting a tropical tree
Authors: Pizo Marco A. , Camargo Paulo H. S. A. 
Published: July 2018

Abstract:Seed dispersal effectiveness (SDE) is related to the role of seed dispersal agents in realizing the reproductive potential of plants through seed dispersal and subsequent plant recruitment. The SDE of a given seed disperser may vary spatially and temporally, with important implications for our understanding of the mutualistic relationships involving plants and frugivores. Here we observed 22 frugivorous bird species visiting an individual tree (Cabralea canjerana) over a 9-y period in a fragment of Atlantic forest in south-eastern Brazil to document the temporal variation in SDE. The quantitative (that takes into account the frequency of feeding visits to the focal plant and the number of fruits removed per visit) and qualitative (that considers the probability of seed deposition on a suitable site for plant recruitment) components of SDE varied in two and one order of magnitude both among bird species and among years within bird species, respectively. As a result, the SDE of bird species fluctuates over the years, especially for a migratory species that is the main seed disperser ofC. canjerana(Chivi vireoVireo chivi) whose quantitative component (i.e. the product of visit and fruit intake rates) varied from 3.0 to 7.1. This study illustrates the dynamic nature of the seed-dispersal environment to which a plant is subjected to over the course of its life, which has important consequences for the plant's individual fitness.
Capsular type K54, clonal group 29 and virulence plasmids: an analysis of K54 and non-K54 closely related isolates ofKlebsiella pneumoniae
Authors: Turton J. F. , Payne Z. , Micah K. , Turton J. A. 
Published: July 2018

AbstractCapsular type K54 ofKlebsiella pneumoniaeis associated with hypervirulence and we sought to discover the basis for this among isolates submitted to the UK reference laboratory between 2012 and 2017. Isolates were typed by variable number tandem repeat analysis, and capsular type and virulence elements sought by PCR. The most prevalent type found (15/31 isolates) corresponded to clonal group (CG) 29 and included five representatives carryingrmpA,rmpA2(regulators of mucoid phenotype),iutAandiroD(from the aerobactin and salmochelin siderophore clusters) associated with virulence plasmids. These included isolate KpvK54, recovered from pus. The remaining isolates did not carry a virulence plasmid. We also noted 11 further related isolates, including NCTC 9159, not of capsular type K54, but nevertheless sometimes associated with sepsis and abscesses. Whole-genome sequencing showed that KpvK54 carried a large virulence plasmid and an ICEKp3-like structure carrying the yersiniabactin cluster, absent in NCTC 9159. Comparative chromosomal analysis with an additional four genomes showed that KpvK54 shared further genes with K1-ST23 hypervirulent isolates, and with LS358, a K54-ST29 isolate from liver abscess puncture fluid. While CG29 isolates displayed varying degrees of virulence, some, especially those with the virulence plasmid (all K54), were clearly associated with hypervirulence.
Interactive effects of age and respiratory virus on severe lower respiratory infection
Authors: Prasad N. , Trenholme A. A. , Huang Q. S. , Thompson M. G. , Pierse N. , Widdowson M. A. , Wood T. , Seeds R. , Taylor S. , Grant C.C. , Newbern E. C. ,   SHIVERS team
Published: July 2018

AbstractWe investigated risk factors for severe acute lower respiratory infections (ALRI) among hospitalised children <2 years, with a focus on the interactions between virus and age. Statistical interactions between age and respiratory syncytial virus (RSV), influenza, adenovirus (ADV) and rhinovirus on the risk of ALRI outcomes were investigated. Of 1780 hospitalisations, 228 (12.8%) were admitted to the intensive care unit (ICU). The median (range) length of stay (LOS) in hospital was 3 (1–27) days. An increase of 1 month of age was associated with a decreased risk of ICU admission (rate ratio (RR) 0.94; 95% confidence intervals (CI) 0.91–0.98) and with a decrease in LOS (RR 0.96; 95% CI 0.95–0.97). Associations between RSV, influenza, ADV positivity and ICU admission and LOS were significantly modified by age. Children <5 months old were at the highest risk from RSV-associated severe outcomes, while children >8 months were at greater risk from influenza-associated ICU admissions and long hospital stay. Children with ADV had increased LOS across all ages. In the first 2 years of life, the effects of different viruses on ALRI severity varies with age. Our findings help to identify specific ages that would most benefit from virus-specific interventions such as vaccines and antivirals.
Tradeoffs in the feed point selection of a cylindrical dielectric resonator antenna
Authors: Ojha Anuj Kumar , Kumar A. V. Praveen 
Published: July 2018

AbstractThis paper aims at investigating the dependence of the impedance and the radiation characteristics of a cylindrical dielectric resonator antenna (DRA), on the feed point of the DRA. It is demonstrated that the resonant frequency, bandwidth, radiation pattern symmetry, and cross-polarized radiation levels depend highly on the feed point. Three standard single-ended feed mechanisms such as the microstrip line, the microstrip slot, and the coaxial probe are taken as examples, to demonstrate the feed-point dependence of the DRA performance. Standard commercial EM simulation tools (ANSYS HFSS and CST Microwave Studio) are used for generating insightful results to help the discussion. This analysis also provides a functional comparison among the above said three feed mechanisms with respect to the feed-point dependence, which is further verified through measurements of DRA prototypes employing the three feeds.
Possible Spatial Distribution of the Mesozoic Volcanic Arc in the Present‐Day South China Sea Continental Margin and Its Tectonic Implications
Authors: Li Fucheng , Sun Zhen , Yang Hongfeng 
Published: July 2018

AbstractThe distribution of the Late Mesozoic volcanic arc in the South China Sea (SCS) continental margin has long been a controversial topic due to its significance in understanding the transition mechanism of a margin from subduction to extension. Here a comprehensive analysis was conducted in the margin using reprocessed magnetic data, newly collected drilling/dredging samples, depositional environment, and deformation style inferred from multichannel seismic profiles to jointly constrain the possible distribution of the Mesozoic volcanic arc. From the map of reduced‐to‐the‐pole magnetic anomaly, several high‐positive magnetic anomaly belts can be discriminated, which cross the central Pearl River Mouth Basin, extend southwestward to the Zhongsha (Macclesfield Bank) and Xisha Islands (Paracel Islands), and distribute discontinuously around the southwest subbasin. Geophysical analysis shows that these belts have similar amplitudes and magnetic depths to known volcanic arcs, such as the Luzon, Cagayan, and Sulu arcs. Furthermore, the high‐amplitude positive magnetic anomaly belts coincide with the distribution of Late Mesozoic arc‐like granites, intermediate rocks, and agglomerates, suggesting that the belts possibly originated from the existence of Late Mesozoic volcanic arc. Accretion and compression environment located in front of the inferred arc provides independent supports to our interpretation. Results indicate that the southwest part of the arc is distributed on both sides of the southwest SCS subbasin, whereas the northeast part remains nearly in its original location, further suggesting that the breakup locations for the SCS margin might be the volcanic front/forearc in the northeast and the arc in the southwest during the opening of the SCS basin.
Flyover Crustal Structures Beneath the Qinling Orogenic Belt and Its Tectonic Implications
Authors: Song Penghan , Teng Jiwen , Zhang Xuemei , Liu Youshan , Si Xiang , Ma Xueying , Qiao Yonghu , Dong Xingpeng 
Published: July 2018

AbstractDetermining high‐resolution three‐dimensional (3‐D) crustal structures of the Qinling Orogenic Belt (QOB) can reveal significant evidences to enhance our understanding of its tectonic evolution. By jointly inverting group and phase velocity dispersion curves, we obtain a high‐resolution 3‐D shear wave velocity model for the QOB. According to the obviously layered features, which include an E‐W trending high‐velocity structure in the upper crust (0–10 km), a transitional zone in the middle crust (10–30 km), and an approximately N‐S trending low‐velocity zone in the middle‐lower crust (20–40 km), we elucidate the crustal structure as a flyover model to explain how the crust beneath the QOB was deformed under the perpendicular force systems from the NE‐SW and E‐W directions during the Meso‐Cenozoic. First, the apparent NE‐SW trending low‐velocity zone in the middle‐lower crust indicates that the low‐viscosity crustal materials beneath the northeastern Tibetan Plateau did not flow eastward into the eastern Qinling terrane during the Cenozoic. Second, the extension in the northern Qinling Mountains and Weihe Basin was not largely affected by the lateral crustal growth of the NE Tibetan Plateau, which might be the result of deep mantle upwelling and/or residual effects from the subduction of the western Pacific plate. Third, during the Mesozoic, the high‐velocity structures beneath the Hannan‐Micang and Shennongjia‐Huangling domes served as anchors resisting the northward subduction, rotation, and continuous collision of the Yangtze Block. The eastward extruding Hannan‐Micang dome served as an indenter that eventually shaped the present‐day asymmetric style of the Dabashan Orocline during the Cenozoic.
Decadal Sedimentation in China's Largest Freshwater Lake, Poyang Lake
Authors: Mei Xuefei , Du Juan , Dai Zhijun , Du Jinzhou , Gao Jinjuan , Wang Jie 
Published: July 2018

AbstractLakes, as key recorders of sedimentation regime variations, have undergone dramatic erosion/deposition worldwide in response to global warming and increasing anthropogenic interference. Poyang Lake, China's largest freshwater lake, has not escaped these variations. Herein, we show that the sedimentation in Poyang Lake has likely undergone a unique phase shift from sediment sink (annually storing 421 × 104 t) during 1960–1999 to sediment source (yearly losing 782 × 104 t) during 2000–2012, with respect to the Changjiang (Yangtze) River. In comparison with sedimentation during 1960–1999, Poyang Lake sedimentation during the period 2000–2012 is characterized by no deposition during the flood season and enhanced erosion during the dry season. Furthermore, Poyang Lake's largest delta, the Ganjiang Delta, prograded at a rate of 32.7 m/a from 1983 to 1996, which increased to 52.8 m/a from 1996 to 2005 but dropped significantly to 1.7 m/a from 2005 to 2015. A sediment core collected in the shallow‐water shoal of the central lake indicates a stable increase in sedimentation flux from 1960 to 2002, with a mean value of 0.27 g/(cm2·a), followed by a decline in sedimentation flux after 2002. Our findings show that the tributary sediment input from the lake catchment dominated the sedimentation of Poyang Lake prior to 2000, when it was significantly larger than the sediment output to the Changjiang River. However, thereafter, the contribution of tributary sediment to the output dropped by 50%, and the rest has been provided by the lake itself. Namely, channels along Poyang Lake's waterway became the additional source of the lake's sediment output in the 2000s.
Lithospheric Architecture and Mantle Metasomatism Linked to Iron Oxide Cu‐Au Ore Formation: Multidisciplinary Evidence from the Olympic Dam Region, South Australia
Authors: Skirrow R. G. , van der Wielen S. E. , Champion D. C. , Czarnota K. , Thiel S. 
Published: July 2018

AbstractThe role of lithospheric architecture and the mantle in the genesis of iron oxide copper‐gold (IOCG) deposits is controversial. Using the example of the Precambrian Gawler Craton (South Australia), which hosts the giant Olympic Dam IOCG deposit, we integrate geophysical data (seismic tomography and magnetotellurics) with geological and geochemical data to develop a new interpretation of the lithospheric setting of these deposits. Spatially, IOCG deposits are located above the margin of a mantle lithospheric zone with anomalously high electrical conductivities (resistivity <10 ohm.m, top at ~100–150 km depth), low seismic shear‐wave velocities (horizontal component, Vsh < 4.6 km/s), and unusually high ratios of compressional‐ to shear‐wave velocities (Vp/Vsh > 1.80). The high conductivity cannot be explained by water‐bearing olivine‐rich rock alone. Relatively fertile and metasomatized peridotitic mantle with additional high‐Vp/Vs phases, for example, clinohumite, hydrous garnet, and/or phlogopite, could explain the anomalous velocity and conductivity. The top of this high‐Vp/Vsh zone marks a midlithospheric discontinuity at ~100–130 km depth that is interpreted to reflect locally orthopyroxene‐rich mantle. A sub‐Moho zone with high Vp/Vsh at ~40–80 km depth correlates spatially with primitive Nd isotope signatures and arc‐related ~1,620–1,610 Ma magmatism and is interpreted as the eclogitic root of a magmatic arc. Mafic volcanics contemporaneous with ~1,590 Ma IOCG mineralization have geochemistry suggesting derivation from subduction‐modified lithospheric mantle. We suggest that Olympic Dam formed inboard of a continental margin in a postsubduction setting, related to foundering of previously refertilized and metasomatized lithospheric mantle. Deposits formed during the switch from compression to extension, following delamination‐related uplift and exhumation.
Subseasonal Dispersal of Freshwater in the Northern Bay of Bengal in the 2013 Summer Monsoon Season
Authors: Sree Lekha J. , Buckley J. M. , Tandon A. , Sengupta D. 
Published: July 2018

AbstractNear‐surface salinity in the north Bay of Bengal (BoB) is very low for nearly three seasons (July–January), due to freshwater input from summer monsoon rainfall and seasonal discharge from several major rivers, including the Ganga‐Brahmaputra‐Meghna and the Irrawady. The low‐salinity surface layer leads to a very shallow density mixed layer, profoundly influencing air‐sea interaction on diurnal to seasonal time scales. We use mooring and satellite observations to study the mechanisms responsible for lateral dispersal of river water in the north BoB on subseasonal time scales (days to weeks) during the summer monsoon season of 2013. A new ocean current data set, the BoB near‐surface current and advection estimation (BoBcat), is developed to account for the influence of near‐surface stratification on directly wind‐forced currents. A salt balance based on Aquarius sea surface salinity, BoBcat currents and moored observations shows that subseasonal sea surface salinity variability is mainly due to lateral advection. A shallow Ekman current, forced by enhanced wind stress during an active spell of the monsoon in mid‐August, plays a dominant role in moving freshwater from the western boundary to the interior. During subseasonal spells of weak monsoon winds, stirring by mesoscale eddies is the main mechanism of dispersal of low‐salinity water. The dispersal of river water in the BoB is very sensitive to surface wind stress.
Local Time Dependence of the Thermal Structure in the Venusian Equatorial Upper Atmosphere: Comparison of Akatsuki Radio Occultation Measurements and GCM Results
Authors: Ando Hiroki , Takagi Masahiro , Fukuhara Tetsuya , Imamura Takeshi , Sugimoto Norihiko , Sagawa Hideo , Noguchi Katsuyuki , Tellmann Silvia , Pätzold Martin , Häusler Bernd , Murata Yasuhiro , Takeuchi Hiroshi , Yamazaki Atsushi , Toda Tomoaki , Tomiki Atsushi , Choudhary Rajkumar , Kumar Kishore , Ramkumar Geetha , Antonita Maria 
Published: July 2018

AbstractTemperature profiles of the Venus atmosphere obtained by the Akatsuki radio occultation measurements showed a prominent local time dependence above 65‐km altitude at low latitudes equatorward of 35°. A zonal wavenumber 2 component is predominant in the temperature field, and its phase (i.e., isothermal) surfaces descend with local time, suggesting its downward phase propagation. A general circulation model (GCM) for the Venus atmosphere, AFES‐Venus, reproduced the local time‐dependent thermal structure qualitatively consistent with the radio occultation measurements. Based on a comparison between the radio occultation measurements and the GCM results, the observed zonal wavenumber 2 structure is attributed to the semidiurnal tide. Applying the dispersion relationship for internal gravity waves to the observed wave structure, the zonally averaged zonal wind speed at 75‐ to 85‐km altitudes was found to be significantly smaller than that at the cloud top. The decrease of the zonal wind speed with altitude is attributed to the momentum deposition by the upwardly propagating semidiurnal tide excited in the cloud layer.
Ice Wedge Degradation and Stabilization Impact Water Budgets and Nutrient Cycling in Arctic Trough Ponds
Authors: Koch J. C. , Jorgenson M. T. , Wickland K. P. , Kanevskiy M. , Striegl R. 
Published: July 2018

AbstractTrough ponds are ubiquitous features of Arctic landscapes and an important component of freshwater aquatic ecosystems. Permafrost thaw causes ground subsidence, creating depressions that gather water, creating ponds. Permafrost thaw also releases solutes and nutrients, which may fertilize these newly formed ponds. We measured water budget elements and chloride, ammonium, and dissolved organic nitrogen (DON) across a chronosequence of trough ponds representing different stages of ice wedge degradation and stabilization. We developed a coupled hydrologic and biogeochemical model to explore how ice wedge degradation affects hydrology and nutrient availability in trough ponds in the advanced degradation stages (DAs), which are characterized by deep troughs with warmer temperatures relative to the other stages. DAs experienced greater evaporation than the other stages, and subsurface inflows entered the DAs from a wide area. Chloride accumulated in the ponds with time since thaw, implying that subsurface fluxes are delivering solutes from the thawing permafrost. Ammonium accumulated at high rates in the initial degradation stage and was seasonally depleted over the summer in all degradation stages. Ammonium trends in the DAs were consistent with high concentration inflows and in‐pond assimilation at rates between 0.37 and 2.0 mg N m−2 day−1. Seasonal DON trends indicated that the accumulation of recalcitrant organic matter may eventually limit aquatic ecosystem production and foster pond infilling. These results provide direct evidence of nutrient release from thawing permafrost and the utilization of these nutrients by Arctic trough pond ecosystems and highlight infilling as a mechanism by which Arctic surface waters may be lost.