bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal variations of triple oxygen isotopic compositions of atmospheric sulfate, nitrate, and ozone at Dumont d'Urville, coastal Antarctica
Authors: Ishino Sakiko , Hattori Shohei , Savarino Joel , Jourdain Bruno , Preunkert Susanne , Legrand Michel , Caillon Nicolas , Barbero Albane , Kuribayashi Kota , Yoshida Naohiro 
Published: March 2017

Abstract. Triple oxygen isotopic compositions (Δ17O  = δ17O − 0.52  ×  δ18O) of atmospheric sulfate (SO42−) and nitrate (NO3−) in the atmosphere reflect the relative contribution of oxidation pathways involved in their formation processes, which potentially provides information to reveal missing reactions in atmospheric chemistry models. However, there remain many theoretical assumptions for the controlling factors of Δ17O(SO42−) and Δ17O(NO3−) values in those model estimations. To test one of those assumption that Δ17O values of ozone (O3) have a flat value and do not influence the seasonality of Δ17O(SO42−) and Δ17O(NO3−) values, we performed the first simultaneous measurement of Δ17O values of atmospheric sulfate, nitrate, and ozone collected at Dumont d'Urville (DDU) Station (66°40′ S, 140°01′ E) throughout 2011. Δ17O values of sulfate and nitrate exhibited seasonal variation characterized by minima in the austral summer and maxima in winter, within the ranges of 0.9–3.4 and 23.0–41.9 ‰, respectively. In contrast, Δ17O values of ozone showed no significant seasonal variation, with values of 26 ± 1 ‰ throughout the year. These contrasting seasonal trends suggest that seasonality in Δ17O(SO42−) and Δ17O(NO3−) values is not the result of changes in Δ17O(O3), but of the changes in oxidation chemistry. The trends with summer minima and winter maxima for Δ17O(SO42−) and Δ17O(NO3−) values are caused by sunlight-driven changes in the relative contribution of O3 oxidation to the oxidation by HOx, ROx, and H2O2. In addition to that general trend, by comparing Δ17O(SO42−) and Δ17O(NO3−) values to ozone mixing ratios, we found that Δ17O(SO42−) values observed in spring (September to November) were lower than in fall (March to May), while there was no significant spring and fall difference in Δ17O(NO3−) values. The relatively lower sensitivity of Δ17O(SO42−) values to the ozone mixing ratio in spring compared to fall is possibly explained by (i) the increased contribution of SO2 oxidations by OH and H2O2 caused by NOx emission from snowpack and/or (ii) SO2 oxidation by hypohalous acids (HOX  =  HOCl + HOBr) in the aqueous phase.
Quantitation of 11 alkylamines in atmospheric samples: separating structural isomers by ion chromatography
Authors: Place Bryan K. , Quilty Aleya T. , Di Lorenzo Robert A. , Ziegler Susan E. , VandenBoer Trevor C. 
Published: March 2017

Abstract. Amines are important drivers in particle formation and growth, which have implications for Earth's climate. In this work, we developed an ion chromatographic (IC) method using sample cation-exchange preconcentration for separating and quantifying the nine most abundant atmospheric alkylamines (monomethylamine (MMAH+), dimethylamine (DMAH+), trimethylamine (TMAH+), monoethylamine (MEAH+), diethylamine (DEAH+), triethylamine (TEAH+), monopropylamine (MPAH+), isomonopropylamine (iMPAH+), and monobutylamine (MBAH+)) and two alkyl diamines (1, 4-diaminobutane (DABH+) and 1, 5-diaminopentane (DAPH+)). Further, the developed method separates the suite of amines from five common atmospheric inorganic cations (Na+, NH4+, K+, Mg2+, Ca2+). All 16 cations are greater than 95 % baseline resolved and elute in a runtime of 35 min. This paper describes the first successful separation of DEAH+ and TMAH+ by IC and achieves separation between three sets of structural isomers, providing specificity not possible by mass spectrometry. The method detection limits for the alkylamines are in the picogram per injection range and the method precision (±1σ) analyzed over 3 months was within 16 % for all the cations. The performance of the IC method for atmospheric application was tested with biomass-burning (BB) particle extracts collected from two forest fire plumes in Canada. In extracts of a size-resolved BB sample from an aged plume, we detected and quantified MMAH+, DMAH+, TMAH+, MEAH+, DEAH+, and TEAH+ in the presence of Na+, NH4+, and K+ at molar ratios of amine to inorganic cation ranging from 1 : 2 to 1 : 1000. Quantities of DEAH+ and DMAH+ of 0.2–200 and 3–1200 ng m−3, respectively, were present in the extracts and an unprecedented amine-to-ammonium molar ratio greater than 1 was observed in particles with diameters spanning 56–180 nm. Extracts of respirable fine-mode particles (PM2. 5) from a summer forest fire in British Columbia in 2015 were found to contain iMPAH+, TMAH+, DEAH+ and TEAH+ at molar ratios of 1 : 300 with the dominant cations. The amine-to-ammonium ratio in a time series of samples never exceeded 0.15 during the sampling of the plume. These results and an amine standard addition demonstrate the robustness and sensitivity of the developed method when applied to the complex matrix of BB particle samples. The detection of multiple alkylamines in the analyzed BB samples indicates that this speciation and quantitation approach can be used to constrain BB emission estimates and the biogeochemical cycling of these reduced nitrogen species.
Rocket in situ observation of equatorial plasma irregularities in the region between E and F layers over Brazil
Authors: Savio Odriozola Siomel , de Meneses Jr. Francisco Carlos , Muralikrishna Polinaya , Pimenta Alexandre Alvares , Kherani Esfhan Alam 
Published: March 2017

Abstract. A two-stage VS-30 Orion rocket was launched from the equatorial rocket launching station in Alcântara, Brazil, on 8 December 2012 soon after sunset (19:00 LT), carrying a Langmuir probe operating alternately in swept and constant bias modes. At the time of launch, ground equipment operated at equatorial stations showed rapid rise in the base of the F layer, indicating the pre-reversal enhancement of the F region vertical drift and creating ionospheric conditions favorable for the generation of plasma bubbles. Vertical profiles of electron density estimated from Langmuir probe data showed wave patterns and small- and medium-scale plasma irregularities in the valley region (100–300 km) during the rocket upleg and downleg. These irregularities resemble those detected by the very high frequency (VHF) radar installed at Jicamarca and so-called equatorial quasi-periodic echoes. We present evidence suggesting that these observations could be the first detection of this type of irregularity made by instruments onboard a rocket.
Reconciling the signal and noise of atmospheric warming on decadal timescales
Authors: Jones Roger N. , Ricketts James H. 
Published: March 2017

Abstract. Interactions between externally forced and internally generated climate variations on decadal timescales is a major determinant of changing climate risk. Severe testing is applied to observed global and regional surface and satellite temperatures and modelled surface temperatures to determine whether these interactions are independent, as in the traditional signal-to-noise model, or whether they interact, resulting in step-like warming. The multistep bivariate test is used to detect step changes in temperature data. The resulting data are then subject to six tests designed to distinguish between the two statistical hypotheses, hstep and htrend. Test 1: since the mid-20th century, most observed warming has taken place in four events: in 1979/80 and 1997/98 at the global scale, 1988/89 in the Northern Hemisphere and 1968–70 in the Southern Hemisphere. Temperature is more step-like than trend-like on a regional basis. Satellite temperature is more step-like than surface temperature. Warming from internal trends is less than 40 % of the total for four of five global records tested (1880–2013/14). Test 2: correlations between step-change frequency in observations and models (1880–2005) are 0.32 (CMIP3) and 0.34 (CMIP5). For the period 1950–2005, grouping selected events (1963/64, 1968–70, 1976/77, 1979/80, 1987/88 and 1996–98), the correlation increases to 0.78. Test 3: steps and shifts (steps minus internal trends) from a 107-member climate model ensemble (2006–2095) explain total warming and equilibrium climate sensitivity better than internal trends. Test 4: in three regions tested, the change between stationary and non-stationary temperatures is step-like and attributable to external forcing. Test 5: step-like changes are also present in tide gauge observations, rainfall, ocean heat content and related variables. Test 6: across a selection of tests, a simple stepladder model better represents the internal structures of warming than a simple trend, providing strong evidence that the climate system is exhibiting complex system behaviour on decadal timescales. This model indicates that in situ warming of the atmosphere does not occur; instead, a store-and-release mechanism from the ocean to the atmosphere is proposed. It is physically plausible and theoretically sound. The presence of step-like – rather than gradual – warming is important information for characterising and managing future climate risk.
Spatial and radiometric characterization of multi-spectrum satellite images through multi-fractal analysis
Authors: Alonso Carmelo , Tarquis Ana M. , Zúñiga Ignacio , Benito Rosa M. 
Published: March 2017

Abstract. Several studies have shown that vegetation indexes can be used to estimate root zone soil moisture. Earth surface images, obtained by high-resolution satellites, presently give a lot of information on these indexes, based on the data of several wavelengths. Because of the potential capacity for systematic observations at various scales, remote sensing technology extends the possible data archives from the present time to several decades back. Because of this advantage, enormous efforts have been made by researchers and application specialists to delineate vegetation indexes from local scale to global scale by applying remote sensing imagery. In this work, four band images have been considered, which are involved in these vegetation indexes, and were taken by satellites Ikonos-2 and Landsat-7 of the same geographic location, to study the effect of both spatial (pixel size) and radiometric (number of bits coding the image) resolution on these wavelength bands as well as two vegetation indexes: the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI). In order to do so, a multi-fractal analysis of these multi-spectral images was applied in each of these bands and the two indexes derived. The results showed that spatial resolution has a similar scaling effect in the four bands, but radiometric resolution has a larger influence in blue and green bands than in red and near-infrared bands. The NDVI showed a higher sensitivity to the radiometric resolution than EVI. Both were equally affected by the spatial resolution. From both factors, the spatial resolution has a major impact in the multi-fractal spectrum for all the bands and the vegetation indexes. This information should be taken in to account when vegetation indexes based on different satellite sensors are obtained.
UMA ANALISE DA MAIOR EPIDEMIA DE DENGUE CLÁSSICA ACONTECIDA NA CIDADE DE CUIABÁ-MT
Authors: Sousa Romário Rosa de , Nascimento José Abel , Silva Blatt Moema Couto 
Published: March 2017

O primeiro caso de dengue clássica em Cuiabá-MT foi registrado no ano de 1991, mas a maior epidemia aconteceu no ano de 2009, quando foram registrados aproximadamente 11.207(onze mil duzentos e sete) casos notificados. Desse total, 90% foram de dengue clássica, 7% referiram-se aos casos graves e 3% referiram-se aos casos de óbito. Considerando esses dados, este trabalho teve como objetivo principal analisar a maior epidemia de dengue clássica acontecida na cidade de Cuiabá-MT, no ano de 2009. Os procedimentos metodológicos adotados se pautaram em 4 (quatro) etapas distintas, sendo a primeira etapa destinada à obtenção dos dados meteorológicos junto ao 9ºDISME/INMET; a segunda etapa destinada à coleta de dados cedidos pela Secretaria Municipal de Saúde – SMS/Centro de Controle de Zoonoses (CCZ) de Cuiabá – MT; a terceira etapa dedicada à obtenção dos dados via sistema SINAN/DATASUS; e a quarta etapa correspondeu às análises e discussões sobre o tema. Constatou-se, na análise empreendida, que nos meses de abril, com 4.534, e maio, com 3.121 casos, foram registrados os maiores números de notificações relacionados à dengue clássica na cidade de Cuiabá-MT, coincidindo este período com o início do outono, imediatamente posterior ao período chuvoso, verão. Os dados diminuíram bruscamente nos meses de junho a outubro, voltando a aumentar as confirmações de dengue nos meses de novembro e dezembro. Dessa forma, visualizou-se que os casos de dengue clássica variam de acordo com as condições atmosféricas.
Information Bodies: Computational Anxiety in Neal Stephenson'sSnow Crash
Authors: Joshua Judy 
Published: March 2017

AbstractCognitive science-based enactive theories of perception afford surprising insight onto a less examined component of perceptual experience: perceptual entrainment through the embodied encounter with tools. My analysis of the body/tool/perception nexus in Neal Stephenson's Snow Crash (1992) introduces the concept of perceptual entrainment in two steps: first I explain Alva Noë's claim that perception is virtual—that it takes place as an active process of environmental investigation rather than through computer-processing-like brain activity. I then take Noë's approach to perception a step further by examining how tool use directs and amplifies our perceptual focus. I argue that in Snow Crash, tools contain within them ideologies of repression that emerge precisely at the “technological interface,” moments when characters in the novel engage with tools that interpellate them, enable them to wield power, or blur the boundaries between control and abjection. This article analyzes the novel's computational anxiety—the fear of loss of self identity via an informational/mathematical determinism mapped by the tool that entrains our perception.
Development and Validation of a Rapid LC-MS/MS Method for Simultaneous Determination of Kaempferol and Quercetin in Thespesia populnea Extract
Authors: Panchal Hiteksha , Shah Mamta B 
Published: March 2017

Abstract
In this study, a simple and rapid LC with tandem MS method was developed and validated for the simultaneous determination of kaempferol and quercetin in Thespesia populnea extract. The compounds were eluted using a Gemini C18 column (50 × 2.0 mm, 3 μm), with the mobile phase consisting of acetonitrile–0.3% formic acid in water at the flow rate of 0.400 mL/min. The assay exhibited a linear dynamic range of 25–2500 ng/mL for both kaempferol and quercetin. The values for intra- and interday precision and accuracy were well within the generally accepted criteria for analytical methods (&lt;15%). Selectivity, linearity, LOD, LOQ, accuracy, and precision were evaluated for both analytes. The proposed method is accurate and sensitive and can be used for the routine quantification of kaempferol and quercetin in the herbal extract and in polyherbal formulations.
Feasibility and acceptability of HIV self‐testing among pre‐exposure prophylaxis users in Kenya
Authors: Ngure Kenneth , Heffron Renee , Mugo Nelly , Thomson Kerry A. , Irungu Elizabeth , Njuguna Njambi , Mwaniki Lawrence , Celum Connie , Baeten Jared M. 
Published: March 2017

AbstractIntroduction: HIV testing is key to the delivery of pre‐exposure prophylaxis (PrEP): testing HIV‐uninfected at‐risk persons is the first step for PrEP initiation and ongoing HIV testing is an essential part of PrEP delivery. Thus, novel and cost‐effective HIV‐testing approaches to streamline delivery of PrEP are urgently needed. Within a demonstration project of PrEP for HIV prevention among high‐risk HIV serodiscordant couples in Kenya (the Partners Demonstration Project), we conducted a pilot evaluation of HIV self‐testing.Methods: Clinic visits were scheduled quarterly and included in‐clinic HIV testing using fingerstick rapid HIV tests and refills of PrEP prescriptions. HIV oral fluid self‐test kits were provided for participants to use in the two‐month interval between scheduled quarterly clinic visits. Acceptability of HIV self‐testing was assessed using both quantitative and qualitative methods.Results: We found that 222 of 226 (98%) HIV‐uninfected persons who were offered accepted self‐testing. Nearly all (96.8%) reported that using the self‐testing kit was easy. More than half (54.5%) reportedly did not share the HIV results from self‐testing with anyone and almost all (98.7%) the participants did not share the HIV self‐testing kits with anyone. Many participants reported that HIV self‐testing was empowering and reduced anxiety associated with waiting between clinic HIV tests.Conclusions: HIV self‐testing was highly acceptable and may therefore be a feasible strategy to efficiently permit routine HIV testing between PrEP refills.
A case study of EMIC waves associated with sudden geosynchronous magnetic field changes
Authors: Kim Khan‐Hyuk , Omura Yoshiharu , Jin Ho , Hwang Junga 
Published: March 2017

AbstractWe present observations of electromagnetic ion cyclotron (EMIC) waves associated with a sudden commencement (SC) on 19 November 2007. In our study, we clearly showed that there was a time delay of ∼10–15 min between the SC onset and the occurrence of EMIC waves at GOES 12 and GOES 10 in the afternoon sector, while the SC‐associated EMIC wave activity observed by GOES 11 in the morning sector started almost immediately after the onset of the SC. This indicates that the EMIC wave source drifts eastward and that magnetospheric compression alone cannot generate EMIC waves without source particles. We suggest that the wave source motion drifting eastward is attributed to the SC‐associated convection electric field, which is slower than the speed of the initial SC disturbance propagating as a fast mode wave. The spectral broadening of EMIC waves for nonlinear wave growth is examined by changing a spatial gradient of the background magnetic field. We have shown that the spectral properties of the observed SC‐associated EMIC waves are in good agreement with the nonlinear theory. In addition, we observed substorm‐associated EMIC wave activity accompanied by a sudden decrease in magnetic field intensity when the satellites were near dusk. By comparing the wave onset times, we confirmed that the substorm‐associated wave source drifted westward.
A new model for predicting the drag exerted by vegetation canopies
Authors: Etminan Vahid , Lowe Ryan J. , Ghisalberti Marco 
Published: March 2017

AbstractThe influence of vegetation canopies on the flow structure in streams, rivers, and floodplains is heavily dependent on the cumulative drag forces exerted by the vegetation. The drag coefficients of vegetation elements within a canopy have been shown to be significantly different from the well‐established value for a single element in isolation. This study investigates the mechanisms that determine canopy flow resistance and proposes a new model for predicting canopy drag coefficients. Large Eddy Simulations were used to investigate the fine‐scale hydrodynamics within emergent canopies with solid area fractions () ranging from 0.016 to 0.25. The influences of three mechanisms in modifying canopy drag, namely, blockage, sheltering, and delayed separation, were investigated. While the effects of sheltering and delayed separation were found to slightly reduce the drag of very sparse canopies, the blockage effect significantly increased the drag of denser canopies (). An analogy between canopy flow and wall‐confined flow around bluff bodies is used to identify an alternative reference velocity in the definition of the canopy drag coefficient; namely, the constricted cross‐section velocity (Uc). Through comparison with both prior experimental data and the present numerical simulations, typical formulations for the drag coefficient of a single cylinder are shown to accurately predict the drag coefficient of staggered emergent canopies whenis used as the reference velocity. Finally, it is shown that this new model can be extended to predict the bulk drag coefficient of randomly arranged vegetation canopies.
Bay of Bengal salinity stratification and Indian summer monsoon intraseasonal oscillation: 2. Impact on SST and convection
Authors: Li Yuanlong , Han Weiqing , Wang Wanqiu , Ravichandran M. , Lee Tong , Shinoda Toshiaki 
Published: March 2017

AbstractThe Indian summer monsoon intraseasonal oscillations (MISOs) induce pronounced intraseasonal sea surface temperature (SST) variability in the Bay of Bengal (BoB), which has important feedbacks to atmospheric convection. An ocean general circulation model (OGCM) is employed to investigate the upper‐ocean processes affecting intraseasonal SST variability and its feedback to the MISO convection. In the BoB, the MISO induces intraseasonal SST variability predominantly through surface heat flux forcing with comparable contributions from shortwave radiation and turbulent heat flux, and to a much smaller extent through wind‐driven ocean mixed layer entrainment. The ocean salinity stratification, represented by mixed layer depth (MLD) and barrier layer thickness (BLT), has a strong control on SST but weak impact on convection of the MISO. The MLD is critical for the amplitude of SST response to various forcing processes, while the BLT mainly affects entrainment by determining the temperature difference between the mixed layer and the water below. From May to mid‐June, the shallow MLD and thin barrier layer greatly enhance intraseasonal SST anomalies, which can amplify convection fluctuations of the MISO through air‐sea interaction and leads to intense but short‐duration postconvection break spells. When either the MLD or the BLT is large, intraseasonal SSTs tend to be weak. Further investigation reveals that freshwater flux of the monsoon gives rise to the shallow MLD and thick barrier layer, and its overall effect on intraseasonal SSTs is a 20% enhancement. These results provide implications for improving the simulation and forecast of the MISO in climate models.
Thank you to 2016 reviewers of Radio Science
Authors: Wilkinson Phil , Salous Sana 
Published: March 2017

AbstractOn behalf of Radio Science, AGU, and the scientific community, the Editors and Associate Editors would like to thank everybody who reviewed manuscripts for Radio Science in 2016. Peer review is widely accepted as an indispensable part of science. The hours spent reading and commenting on manuscripts not only improves the manuscripts themselves, but it also ensures the scientific rigor of future research in our field. These contributions are vital. Many of those listed below went further and reviewed three or more manuscripts for Radio Science, and they are indicated in italics. Overall, Radio Science had 547 individuals provide reviews of 382 manuscripts. Thank you once again to all our reviewers for contributing your valuable time to this essential task. We look forward to a 2017 of exciting advances in our field and communicating those advances to our community and to the broader public.