bluuebunny/crossref_metadata_2025 huggingface dataset:
IDENTIFYING FARMERS’ PREFERENCES AND CONSTRAINTS TO PEARL MILLET PRODUCTION IN THE SAHEL AND NORTH-SUDAN ZONES OF BURKINA FASO
Authors: DRABO INOUSSA , ZANGRE ROGER G. , DANQUAH ERIC Y. , OFORI KWADWO , WITCOMBE JOHN R. , HASH C. TOM
Published: September 2018

The low yield of pearl millet largely due to the low adoption of improved varieties substantiates the application of client-oriented plant breeding for pearl millet. Hence to enhance adoption, new varieties must correspond to farmers’ preferences and respond to the constraints prevailing in the production environments, participatory rural appraisals were conducted in two agro-ecological zones (Sahel and North-Sudan) to determine farmers’ preferences in the choice of varieties and to identify constraints to pearl millet production. The study revealed that the major production constraints are hierarchically drought, Striga, head miner, bird and downy mildew. Compact panicle, large grain size and non-bristle panicle were the most preferred traits in pearl millet across agro-ecological zones. Very long panicle and early maturity crop cycle were more preferred in the Sahel zone whereas, in the North-Sudan zone medium panicle length and medium maturity cycle were more preferred by farmers. Traits largely rejected by farmers were small grain size, narrow, loose and bristled panicle. Very few investigations were done to understand the raison of the low adoption of improved technologies in pearl millet. This study identified the major criteria of new pearl millet variety adoption by farmers. It is expected that breeding program must integrate these criteria in new pearl millet variety profiling to enhance adoption.
Growth performance of finishing feedlot lambs fed maize silage inoculated withBacillus subtilisand lactic acid bacteria
Authors: Rabelo C. H. S. , Lara E. C. , Basso F. C. , Härter C. J. , Reis R. A.
Published: September 2018

Whole-crop maize forage was ensiled without inoculant (control), inoculated withLactobacillus buchneriandL. plantarumat a rate of 1 × 105cfu/g fresh forage per bacterium (LBLP), or inoculated withBacillus subtilisandL. plantarumat a rate 1 × 105cfu/g fresh forage per bacterium (BSLP) with the goal to investigate the growth performance of finishing feedlot lambs. Thirty Dorper × Santa Ines lambs (29 ± 3.5 kg initial body weight) were used in the feedlot programme and assigned (n= 10) to one of three diets containing control, LBLP or BSLP silages in a 60:40 forage:concentrate ratio. Inoculation of maize silage did not alter dry matter intake (overall mean = 1.16 kg/day) and average daily gain (overall mean = 0.217 kg/day) of lambs. Consequently, feed efficiency remained unchanged. Inoculation of maize silage did not alter carcass and meat traits of lambs, with the exception of meat colour, wherein yellowness (b*) decreased by feeding LBLP and BSLP diets compared with the untreated diet. Regarding ruminal fermentation, there was an interaction between diets and the interval at which ruminal fluid was sampled for determining total volatile fatty acid concentration, but inoculation yielded no obvious results. In conclusion, the use of diets based on maize silage inoculated withL. plantarumcombined with eitherL. buchneriorB. subtilisdid not display relevant effects on growth performance of lambs; this response might be related to the limited impact of these bacterial inoculants on silage composition.
Genetic variation in Irish Sea brown crab (Cancer pagurusL.): implications for local and regional management
Authors: McKeown Niall J. , Watson Hayley V. , Coscia Ilaria , Wootton Emma , Ironside Joseph E.
Published: September 2018

Understanding demographic processes over multiple spatial scales is vital for the optimization of conservation/management strategies, particularly for commercially harvested taxa such as the brown crab (Cancer pagurusL). Brown crab population genetic structure was investigated at (i) a local scale within the Irish Sea, which included comparisons with the Lundy No Take Zone (NTZ) and (ii) across the NE Atlantic. The results indicate that the brown crab does not exhibit strong spatial structure either within the Irish Sea or at the regional level, suggesting high gene flow within and among the Irish Sea, English Channel and North Sea. Comparisons between the Lundy NTZ and harvested areas revealed similarly high levels of genetic diversity. An intriguing result was that the Lundy NTZ sample exhibited a degree of genetic patchiness (ephemeral geographically unpatterned differentiation) which may indicate elevated recruitment skews within the NTZ. Overall, the results support the view that brown crabs within the sampled area belong to a single genetically panmictic stock and that if breeding stock sizes are maintained genetic drift will not be strong enough to reduce neutral genetic diversity. The highly connected nature of this species requires international cooperation for sustainable management, an important component of which will be the application of more powerful population genomic approaches to assess finer scale aspects of stock structure as well drivers of genetic patchiness reported for the species. This is a timely consideration in light of potential future misalignments between biological and geopolitical stock boundaries in the Irish Sea following Brexit.
Prevalence of suicide attempt in individuals with major depressive disorder: a meta-analysis of observational surveys
Authors: Dong Min , Zeng Liang-Nan , Lu Li , Li Xiao-Hong , Ungvari Gabor S. , Ng Chee H. , Chow Ines H. I. , Zhang Ling , Zhou Yuan , Xiang Yu-Tao
Published: September 2018

Background

Suicide attempt (SA), which is one of the strongest predictors of completed suicide, is common in major depressive disorder (MDD) but its prevalence across epidemiological studies has been mixed. The aim of this comprehensive meta-analysis was to examine the pooled prevalence of SA in individuals with MDD.

Methods

A systematic literature search was conducted in PubMed, Embase, PsycINFO, Web of Science and Cochrane Library from their commencement date until 27 December 2017. Original studies containing data on prevalence of SA in individuals with MDD were analyzed.

Results

In all, 65 studies with a total of 27 340 individuals with MDD were included. Using the random effects model, the pooled lifetime prevalence of SA was 31% [95% confidence interval (CI) 27–34%], 1-year prevalence was 8% (95% CI 3–14%) and 1-month prevalence was 24% (95% CI 15–34%). Subgroup analyses revealed that the lifetime prevalence of SA was significantly associated with the patient setting, study region and income level, while the 1-month prevalence of SA was associated with only the patient setting.

Conclusion

This meta-analysis confirmed that SA was common in individuals with MDD across the world. Careful screening and appropriate interventions should be implemented for SA in the MDD population.
In vitro virucidal activity of sodium hypochlorite against canine parvovirus type 2
Authors: Cavalli A. , Marinaro M. , Desario C. , Corrente M. , Camero M. , Buonavoglia C.
Published: September 2018

Canine parvovirosis is a very contagious, severe and often lethal infectious disease of dogs caused by canine parvovirus type 2 (CPV-2). Parvoviruses are very resistant to several disinfectants while are sensitive to halogens such as sodium hypochlorite which is often used for decontamination of veterinary clinics and animal housing facilities due to its broad spectrum of activity. If compliance with vaccination programmes and with proper disinfection plans is ensured, there should be no continuous, nor frequent, CPV-2 outbreaks in kennels and veterinary clinics. However, a continuous spread of CPV-2 infections is observed, even in kennels where an appropriate vaccination programme is applied, and this imposes a re-evaluation of disinfection protocols using sodium hypochlorite. The aim of the present study was to determine the effect of concentration, contact time and presence of organic matter on the virucidal activity of sodium hypochlorite against several CPV-2 strains. A sensitive in vitro assay capable of measuring the infectivity of CPV-2 was employed to determine the efficacy of three different concentrations of sodium hypochlorite. The data indicate that using a 0.75% sodium hypochlorite solution for a short contact time (1 min) can reduce significantly the CPV-2 titres and that even lower concentrations, i.e. 0.37%, can efficiently inactivate the viruses provided that the contact time is extended to 15 min. Results also confirm the importance of cleaning before disinfection since the presence of organic matter totally abrogated the virucidal activity of sodium hypochlorite solutions against the three CPV-2 strains.
What changes when? A reply to Beauchaine and Slep
Authors: Weeland Joyce , Chhangur Rabia R. , Jaffee Sara R. , van der Giessen Danielle , Matthys Walter , Orobio de Castro Bram , Overbeek Geertjan
Published: September 2018

In their commentary, Beauchaine and Slep (2018) raise important issues regarding research on behavioral parenting training (BPT). In this reply we highlight key points of agreement and respond to issues that we feel require clarification. BPT has been repeatedly proven effective in decreasing disruptive child behavior (also in the work of our research team). Yet, there is much to learn about for whom and how BPT is effective. Specifically, assessing the how (i.e., mediation) comes with many challenges. One of these challenges is taking into account the timeline of change, and being able to infer causal mechanisms of change. We argue that cross-lagged panel models (which we, and many other scholars, used) are a valid and valuable method for testing mediation. At the same time, our results raise important questions, specifically about the timing and form of expected changes in parenting and child behavior after BPT. For example, are these changes linear and gradual or do they happen more suddenly? To select the appropriate design, assessment tools, and statistical models to test mediation, we need to state detailed hypotheses on what changes when. An important next step might be to assess multiple putative mediators on different timescales, not only before and after, but specifically also during BPT.
Estimated vitamin D synthesis and dietary vitamin D intake among Asians in two distinct geographical locations (Kuala Lumpur, 3°N v. Aberdeen, 57°N) and climates
Authors: Jamil Nor Aini , Yew Meng Hooi , Noor Hafizah Yatiman , Gray Stuart R , Poh Bee Koon , Macdonald Helen M
Published: September 2018

Objective

To compare the contributions of UVB exposure and diet to total vitamin D among Asians living in Kuala Lumpur (KL) and Aberdeen (AB).

Design

Longitudinal study.

Setting

UVB exposure (using polysulfone film badges) and skin colour and dietary vitamin D intake (by web-based questionnaire) were measured at each season in AB and during south-west (SWM) and north-east monsoons (NEM) in KL.

Subjects

One hundred and fifteen Asians in KL and eighty-five Asians in AB aged 20–50 years.

Results

Median summer UVB exposure of Asians in AB (0·25 SED/d) was higher than UVB exposure for the KL participants (SWM=0·20 SED/d, P=0·02; NEM= 0·14 SED/d, P<0·01). UVB exposure was the major source of vitamin D in KL year-round (60%) but only during summer in AB (59%). Median dietary vitamin D intake was higher in AB (3·50 µg/d (140 IU/d)), year-round, than in KL (SWM=2·05 µg/d (82 IU/d); NEM=1·83 µg/d (73 IU/d), P<0·01). Median total vitamin D (UVB plus diet) was higher in AB only during summer (8·45 µg/d (338 IU/d)) compared with KL (SWM=6·03 µg/d (241 IU/d), P=0·04; NEM=5·35 µg/d (214 IU/d), P<0·01), with a comparable intake across the full year (AB=5·75 µg/d (230 IU/d); KL=6·15 µg/d (246 IU/d), P=0·78).

Conclusions

UVB exposure among Asians in their home country is low. For Asians residing at the northerly latitude of Scotland, acquiring vitamin D needs from UVB exposure alone (except in summer) may be challenging due to low ambient UVB in AB (available only from April to October).
Laboratory measurements of methanol photolysis branching ratios to guide astrochemical models
Authors: Weaver Susanna Widicus , Powers Carson R. , McCabe Morgan N. , Zinga Samuel
Published: September 2018

Methanol is ubiquitous in star-forming regions, and has recently been detected in a protoplanetary disk. Astrochemical models have shown that methanol photolysis contributes to complex organic chemistry in interstellar ices. While some methanol photolysis branching ratios have been measured, infrared condensed-phase measurements rely on assumptions about the chemistry, and mass spectrometric measurements cannot distinguish structural isomers. To address these challenges, we are using pure rotational spectroscopy to quantitatively probe the methanol photolysis products. We use a VUV laser to dissociate methanol in the throat of a supersonic expansion, and probe the products downstream after cooling is complete. We then use a rotational diagram analysis to determine the relative density of each product relative to methanol. We have detected the methoxy, hydroxymethyl, and formaldehyde photolysis products. We present here the experimental setup and the initial results and discuss these results in the context of interstellar chemistry.
Chemistry of the oldest white dwarf planetary systems
Authors: Hollands Mark A. , Gänsicke Boris T. , Koester Detlev , Alekseev Vadim , Herbert Emma L.
Published: September 2018

Almost all stars in the Milky Way, including the Sun, will end their lives as white dwarfs. Their relatively peaceful transition off of the main sequence implies that most of their planetary systems will survive engulfment during the deaths of their host stars. These remnant planetary systems remain detectable for many Gyr through the occasional metal-contamination of the white dwarf photospheres by tidally disrupted planetesimals. Spectral analysis of these “metal-polluted” white dwarfs therefore provides a direct method for measuring the chemical compositions of extrasolar material. Here we present our sample of 230 cool white dwarfs with metal-rich photospheres, explore the diverse range of compositions of the accreted matter, and discuss two extreme systems which have respectively accreted planetesimals consistent with crust-like and core-like planetary material.
The Abundance of SiC2 in Carbon Star Envelopes
Authors: Massalkhi Sarah , Agúndez M. , Cernicharo J. , Fonfría J. P. , Santander-García M.
Published: September 2018

Silicon carbide dust grains are ubiquitous in circumstellar envelopes around C-rich AGB stars. However, the main gas-phase precursors leading to the formation of SiC dust have not yet been identified. To date, only three molecules containing an Si–C bond have been identified to have significant abundances in C-rich AGB stars: SiC2, SiC, and Si2C. The ring molecule SiC2 has been observed in a handful of evolved stars, while SiC and Si2C have only been detected in the C-star envelope IRC +10216. We aim to study how widespread and abundant SiC2, SiC, and Si2C are in envelopes around C-rich AGB stars and whether or not these species play an active role as gas-phase precursors of silicon carbide dust in the ejecta of carbon stars.
Shocks and UV radiation around low-mass protostars: the Herschel-PACS legacy
Authors: Karska Agata , Kaufman Michael J. , Kristensen Lars E. , van Dishoeck Ewine F. ,   WISH, DIGIT, and WILL teams
Published: September 2018

Far-infrared spectroscopy reveals gas cooling and its underlying heating due to physical processes taking place in the surroundings of protostars. These processes are reflected in both the chemistry and excitation of abundant molecular species. Here, we present the Herschel-PACS far-IR spectroscopy of 90 embedded low-mass protostars from the WISH (van Dishoeck et al. 2011), DIGIT (Green et al. 2013), and WILL surveys (Mottram et al. 2017). The 5 × 5 spectra covering the ∼50″ × 50″ field-of-view include rotational transitions of CO, H2O, and OH lines, as well as fine-structure [O I] and [C II] in the ∼50-200 μm range. The CO rotational temperatures are typically ∼300 K, with some sources showing additional components with temperatures as high as ∼1000 K. The H2O / CO and H2O / OH flux ratios are low compared to stationary shock models, suggesting that UV photons may dissociate some H2O and decrease its abundance. Comparison to C shock models illuminated by UV photons show a good agreement between the line emission and the models for pre-shock densities of 105 cm−3 and UV fields 0.1-10 times the interstellar value. The far-infrared molecular and atomic lines are the unique diagnostic of shocks and UV fields in deeply-embedded sources.
Fire from Ice - Massive Star Birth from Infrared Dark Clouds
Authors: Tan Jonathan C.
Published: September 2018

I review massive star formation in our Galaxy, focussing on initial conditions in Infrared Dark Clouds (IRDCs), including the search for massive pre-stellar cores (PSCs), and modeling of later stages of massive protostars, i.e., hot molecular cores (HMCs). I highlight how developments in astrochemistry, coupled with rapidly improving theoretical/computational and observational capabilities are helping to improve our understanding of the complex process of massive star formation.
The chemical connection between 67P/C-G and IRAS 16293-2422
Authors: Drozdovskaya Maria Nikolayevna , van Dishoeck Ewine F. , Rubin Martin , Jørgensen Jes Kristian , Altwegg Kathrin
Published: September 2018

The chemical evolution of a star- and planet-forming system begins in the prestellar phase and proceeds across the subsequent evolutionary phases. The chemical trail from cores to protoplanetary disks to planetary embryos can be studied by comparing distant young protostars and comets in our Solar System. One particularly chemically rich system that is thought to be analogous to our own is the low-mass IRAS 16293-2422. ALMA-PILS observations have made the study of chemistry on the disk scales (<100 AU) of this system possible. Under the assumption that comets are pristine tracers of the outer parts of the innate protosolar disk, it is possible to compare the composition of our infant Solar System to that of IRAS 16293-2422. The Rosetta mission has yielded a wealth of unique in situ measurements on comet 67P/C-G, making it the best probe to date. Herein, the initial comparisons in terms of the chemical composition and isotopic ratios are summarized. Much work is still to be carried out in the future as the analysis of both of these data sets is still ongoing.
The Remarkable Molecular Content of Planetary Nebulae
Authors: Schmidt D. R. , Ziurys L. M.
Published: September 2018

In order to further define the molecular content of planetary nebulae (PNe), we have conducted searches for HCN, HCO+, HNC, and CCH at millimeter wavelengths in a sample of seventeen PNe using the new 12 m and Sub-Millimeter Telescopes of the Arizona Radio Observatory (ARO). HCN and HCO+ were identified in 75% of the PNe, with corresponding fractional abundances of f(HCN/H2) ~ 0.1-9.1 × 10−7 and f(HCO+/H2) ~ 0.04-7.4 × 10−7. HNC was subsequently identified in twelve PNe with f(HNC/H2) ~ 0.02-2.2 × 10−7. The [HCN]/[HNC] ratio was found to be ~1-8 in nebulae observed. CCH was also detected in eight PNe. The abundances for all molecules were found to remain relatively constant with nebular age across 10,000 years, in contrast to model predictions. They are also 10-100 greater than those observed in diffuse clouds, and suggest that molecular material from PNe seed the diffuse ISM.
Recent Progress in Laboratory Astrophysics Achieved with NASA Ames’ COSmIC Facility
Authors: Salama Farid , Sciamma-O’Brien Ella , Contreras Cesar S. , Bejaoui Salma
Published: September 2018

We describe the characteristics and the capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to generate, process and analyze interstellar, circumstellar and planetary analogs in the laboratory. COSmIC stands for ’Cosmic Simulation Chamber’ and is dedicated to the study of neutral and ionized molecules and nanoparticles under the low temperature and high vacuum conditions that are required to simulate various space environments such as diffuse interstellar clouds, circumstellar outflows and planetary atmospheres. Recent results obtained using COSmIC will be highlighted. In particular, the progress that has been achieved in the domain of the diffuse interstellar bands (DIBs) and in monitoring, in the laboratory, the formation of circumstellar dust grains and planetary atmosphere aerosols from their gas-phase molecular precursors. Plans for future laboratory experiments on interstellar and planetary molecules and grains will also be addressed, as well as the implications of the studies underway for astronomical observations and past and future space mission data analysis.
Forging Women's Substantive Representation: Intersectional Interests, Political Parity, and Pensions in Bolivia
Authors: Ewig Christina
Published: September 2018

Lacking tools to measure substantive representation, empirical research to date has determined women’s substantive representation by identifying “women’s interests” a priori, with little attention to differences across race, class, or other inequalities. To address this problem, I develop the concept of intersectional interests and a method for identifying these. Intersectional interests represent multiple perspectives and are forged through a process of political intersectionality that purposefully includes historically marginalized perspectives. These interests can be parsed into three types: expansionist, integrationist, and reconceived. Identification of intersectional interests requires, first, an inductive mapping of the differing women’s perspectives that exist in a specific context and then an examination of the political processes that lead to these new, redefined interests. I demonstrate the concept of intersectional interests and how to identify these in Bolivia, where I focus on the political process of forging reconceived intersectional interests in Bolivia’s political parity and pension reforms.
Facts and Fiction: The Myth of Suvaṇṇabhūmi Through the Thai and Burmese Looking Glass
Authors: Revire Nicolas
Published: September 2018

Most scholars think that the generic name ‘Golden Land’ (Sanskrit, Suvarṇabhūmi; Pali, Suvaṇṇabhūmi) was first used by Indian traders as a vague designation for an extensive region beyond the subcontinent, presumably in Southeast Asia. Some Pali sources specifically link Suvaṇṇabhūmi with the introduction of Buddhism to the region. The locus classicus is the Sri Lankan Mahāvaṃsa chronicle (fifth century AD) which states that two monks, Soṇa and Uttara, were sent there for missionary activities in the time of King Asoka (third century BC). However, no Southeast Asian textual or epigraphic sources refer to this legend or to the Pali term Suvaṇṇabhūmi before the second millennium AD. Conversely, one may ask, what hard archaeological evidence is there for the advent of Buddhism in mainland Southeast Asia? This article re-examines the appropriation of the name Suvaṇṇabhūmi in Thailand and Burma for political and nationalist purposes and deconstructs the connotation of the term and what it has meant to whom, where, and when. It also carefully confronts the Buddhist literary evidence and earliest epigraphic and archaeological data, distinguishing material discoveries from legendary accounts, with special reference to the ancient Mon countries of Rāmaññadesa (lower Burma) and Dvāravatī(central Thailand).
Anticyclonic Eddy Edge Effects on Phytoplankton Communities and Particle Export in the Northern South China Sea
Authors: Wang Lei , Huang Bangqin , Laws Edward A. , Zhou Kuanbo , Liu Xin , Xie Yuyuan , Dai Minhan
Published: September 2018

We examined response of phytoplankton total chlorophyll a (TChl a) and community composition to three coherent anticyclonic eddies (ACEs) observed during a cruise to the northern South China Sea on 28 July to 7 August 2007. Photosynthetic pigments were measured to estimate the contribution of nine phytoplankton groups to TChl a. Although the water column‐integrated TChl a inventory in the upper 100 m was very similar among the three ACEs (17.6–18.9 mg/m2) we observed during the cruise, there were remarkable enhancements in biomasses at the eddy edges. TChl a inventory was 20.8 ± 3.0 mg/m2 at the edge, which was 33% or 60% higher than at the center and reference. The greatest enhancement of the TChl a at edge was attributed to haptophyte‐8, which was 1.6 and 2.2 times the analogous concentrations at the center and reference sites. The Prochlorococcus Chl a was ~50% greater at the edge relative to the reference and was intermediate at the center. Diatom Chl a at the edge was ~2.5 times the concentrations at the center and reference sites. The positive correlation between particulate organic carbon flux and haptophyte‐8 Chl a at the edge implied an important role of haptophyte‐8 in particle export productivity. It is interesting to note that there occurred higher fluxes of biogenic Si at the center of the ACEs due likely to lateral transport of diatoms from the edge. The phenomenon of higher TChl a at the edge but higher export at the center may have been the combined result of vertical convection and lateral transport within the eddies.
Emergent Wave Conversion as a Precursor to Shear Crack Initiation
Authors: Modiriasari Anahita , Pyrak‐Nolte Laura J. , Bobet Antonio
Published: September 2018

Geophysical assessments of subsurface instability rely on a link between physical failure mechanisms and a geophysical measurement. Here a laboratory study demonstrates the emergence of a converted phase at the damage onset in limestone prior to failure from shear crack formation. Shear (S) to compressional (P) wave conversions arise from the presence of an array of disconnected microcracks and occur prior to the crack initiation detection from surface displacement measurements. The converted waves increase in amplitude with shear crack propagation until crack coalescence. The inception of the S to P wave converted phase supports the use of elastic wave conversions as an active diagnostic tool to detect the initiation and propagation of shear cracks.
Asymmetry in Stimulated Emission Polarization and Irregularity Evolution During Ionospheric Electron Gyroharmonic Heating
Authors: Fu H. Y. , Scales W. A. , Bernhardt P. A. , Jin Y. Q. , Briczinski S. J.
Published: September 2018

The first report is made of a holistic investigation of stimulated electromagnetic emission (SEE) during ionospheric electron gyroharmonic heating using a diagnostic approach at the High Frequency Active Auroral Research Program facility. The evolution of SEE polarization and plasma irregularity development near the third electron gyroharmonic 3fce is investigated, which provides new insights into SEE generation mechanisms by the associated parametric decay instabilities. New more complex SEE spectral line behavior is clearly observed for varying transmitter beam angles. New SEE spectral emissions are observed at ∼75 kHz when pumping below 3fce. The high‐frequency radar echoes and SEE polarimetry appear asymmetric for pumping above 3fce, which implies that the broad upshifted maximum spectral line formation involves plasma irregularities scattered by high‐frequency radar echoes. This has important implications for understanding artificial ionization layer generation during ionospheric modification.
Juno Constraints on the Formation of Jupiter's Magnetospheric Cushion Region
Authors: Gershman Daniel J. , DiBraccio Gina A. , Connerney John E. P. , Bagenal Fran , Kurth William S. , Hospodarsky George B. , Spalsbury Lori , Clark George , Ebert Robert W. , Wilson Robert J. , Levin Steve , Bolton Scott J.
Published: September 2018

Observations by the Pioneer, Voyager, Ulysses, and Galileo spacecraft in Jupiter's dayside magnetosphere revealed a cushion region, where the magnetic field became increasingly dipolar and the 10‐hr periodicity associated with rotation of the magnetodisc was no longer visible. Focused observations at the dawn terminator by the Juno spacecraft provide critical constraints on the formation physics of the dayside cushion. We observe a persistent 10‐hr periodicity at dawn with only minor distortions of the field near the magnetopause boundary, indicating the absence of a systematic dawn cushion region. These data suggest that the dayside cushion is not formed via mass loss associated with magnetic reconnection along a localized X line but rather may be due to the gradual compression of the dawnside magnetic field as it rotates toward local noon.
Diversity of ENSO Events Unified by Convective Threshold Sea Surface Temperature: A Nonlinear ENSO Index
Authors: Williams Ian N. , Patricola Christina M.
Published: September 2018

We show that the well‐known failure of any single index to capture the diversity and extremes of El Niño‐Southern Oscillation (ENSO) results from the inability of existing indices to uniquely characterize the average longitude of deep convection in the Walker Circulation. We present a simple sea surface temperature (SST)‐based index of this longitude that compactly characterizes the different spatial patterns, or flavors of observed and projected ENSO events. It recovers the familiar global responses of temperature, precipitation, and tropical cyclones to ENSO and identifies historical extreme El Niño events. Despite its simplicity, the new longitude index describes the nonlinear relationship between the first two principal components of SST, and unlike previous indices, accounts for background SST changes associated with the seasonal cycle and climate change. The index reveals that extreme El Niño, El Niño Modoki, and La Niña events are projected to become more frequent in the future at the expense of neutral ENSO conditions.
Differential Impacts of 1.5 and 2 °C Warming on Extreme Events Over China Using Statistically Downscaled and Bias‐Corrected CESM Low‐Warming Experiment
Authors: Yang Yi , Tang Jianping , Wang Shuyu , Liu Gang
Published: September 2018

Using statistically downscaled and bias‐corrected CESM (Community Earth System Model) 11‐member ensemble, we investigate the changes in precipitation and temperature extremes over China in 1.5 and 2 °C warmer climates. Most regions will experience a significant increase in wet extreme indices accompanied by fewer consecutive dry days under both warming targets. An additional 0.5 °C warming may result in stronger increases in wet extreme indices over most subregions and weak decreases over North China, although the grid point‐level changes between the two scenarios are mostly nonsignificant. A robust increase in extreme high‐temperature events and TNn (the coldest night) is found across China at a 2 °C relative to 1.5 °C scenario. Compared to a 2 °C world, a 0.5 °C less warming avoids 32–34% of the increases in the frequency and intensity of temperature extremes in China, particularly over Northeast China.
Experimental Determination of Eutectic Liquid Compositions in the MgO‐SiO2System to the Lowermost Mantle Pressures
Authors: Ozawa Keisuke , Anzai Miyuki , Hirose Kei , Sinmyo Ryosuke , Tateno Shigehiko
Published: September 2018

We have performed melting experiments on the MgO‐SiO2binary system to 139 GPa in a diamond anvil cell. Both MgO‐MgSiO3and MgSiO3‐SiO2eutectic compositions were examined by textural/chemical characterizations of recovered samples. Results demonstrate that the MgO‐MgSiO3eutectic becomes more enriched in MgO with increasing pressure and is close in composition to Mg2SiO4at the core‐mantle boundary (CMB) pressure. On the other hand, the MgSiO3‐SiO2eutectic is more SiO2‐rich at higher pressure and exhibits SiO2/(MgO + SiO2) = 0.66 at the CMB. These have profound implications for a large‐scale compositional stratification possibly formed upon solidification of a magma ocean. The MgO‐MgSiO3eutectic liquid being more MgO‐rich than previously predicted suggests that only bridgmanite crystallizes up to 60 wt% solidification from a fully molten state of a pyrolitic lowermost mantle. In contrast, an SiO2layer may develop when melting/crystallization occurs in rocky objects with silica‐rich enstatite‐chondritic compositions.
Reconsidering Effective Elastic Thickness Estimates by Incorporating the Effect of Sediments: A Case Study for Europe
Authors: Kaban M. K. , Chen B. , Tesauro M. , Petrunin A. G. , El Khrepy S. , Al‐Arifi N.
Published: September 2018

In the present study we analyzed the influence of density heterogeneity in the sedimentary cover on estimates of the effective elastic thickness (EET) of the lithosphere based on a cross‐spectral analysis of gravity and topography data. The fan wavelet coherence technique was employed to calculate EET for most of Europe and adjoining southern mountain belts. We employed Bouguer gravity anomalies and topography corrected for the effect of density variations within sediments. Correcting for sediments considerably suppresses the effect of unexpressed subsurface loads and substantially reduces EET estimates in areas with negligible topography variations as it was demonstrated for North Europe and East European Platform. The results show a good correspondence between the EET patterns and tectonic fragmentation of Europe and better agree with independent estimates based on the strength model of the lithosphere. Therefore, considering of the effect of sediments is essential for correct determinations of EET in flat areas.
A Tenuous Lunar Ionosphere in the Geomagnetic Tail
Authors: Halekas J. S. , Poppe A. R. , Harada Y. , Bonnell J. W. , Ergun R. E. , McFadden J. P.
Published: September 2018

We utilize measurements of electron plasma frequency oscillations made by the two‐probe Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun mission to investigate the charged particle density in the lunar environment as the Moon passes through the Earth's geomagnetic tail. We find that the Moon possesses a tenuous ionosphere with an average density of ~0.1–0.3 cm−3, present at least 50% of the time in the geomagnetic tail, primarily confined to within a few thousand kilometers of the dayside of the Moon. The day‐night asymmetry and dawn‐dusk symmetry of the observed plasma suggests that photoionization of a neutral exosphere with dawn‐dusk symmetry produces the majority of the lunar‐derived plasma. The lunar plasma density commonly exceeds the ambient plasma density in the tail, allowing the presence of the lunar ionosphere to appreciably perturb the local plasma environment.
Permeability Evolution of a Cemented Volcanic Ash During Carbonation and CO2 Depressurization
Authors: Clark A. C. , MacFarlane J. , Vanorio T.
Published: September 2018

The presence of calcium‐cemented ash beds serving as caprocks in hydrothermal systems calls for the examination of any chemo‐mechanical processes that may undermine or enhance their sealing capacity. Understanding these processes provides new information regarding how to model time‐dependent observations associated with seismicity and/or deformation in volcanic areas. In addition, since these ash beds are inherently similar to ash‐based concrete, a bridge of knowledge can be built across disciplines in the earth sciences and engineering. This paper investigates how the permeability of a volcanic ash cemented with hydrated lime changes upon exposure to carbon dioxide (CO2) in humid and hydrous conditions relevant to natural or human‐driven processes such as those found in hydrothermal settings or near wellbores used for secondary oil recovery, CO2 plume geothermal energy, or carbon storage. We characterized samples by their permeability during carbonation and subsequent changes in pore pressure and confining pressure. Products from the reaction of CO2 with the cemented ash matrix reduced permeability and entrapped fluids. The regions within samples permeated with unreacted CO2 were susceptible to fracturing upon rapid depressurization, but only when the effective stress state was sufficiently low. Altogether, the results indicate that lime‐cemented volcanic ash beds are particularly suited to act as flow barriers to CO2‐rich fluids.
Observations of the Intermediate Water Exchange Between the South China Sea and the Pacific Ocean Deduced From Transient Tracer Measurements
Authors: Deng Hengxiang , Huang Peng , Tanhua Toste , Stöven Tim , Ke Hongwei , Guo Weidong , Wang Weimin , Cai Minggang
Published: September 2018

The South China Sea (SCS) is the largest semienclosed marginal sea in the western Pacific (WP) and connects to the west Pacific through the Luzon Strait (LU). In this study, we use the observation of transient tracer chlorofluorocarbon‐12 (CFC‐12) to calculate the ventilation time scales of the SCS, LU, and WP. The CFC‐12 and oxygen data are used together to identify the sandwiched structure vertically of the flows across the LU. The CFC‐12 and oxygen distributions reveal a pronounced decrease westward across the LU and a slight decrease southward in the transport of the SCS. The mean age gradient of the salinity minimum (Smin) water between the WP and the northern SCS could be a consequence of intensive mixing and entrainment of the inflow water from the WP. An expected difference in age between the LU and SSCS is verified to reflect the transit time for the given water layers in the SCS. Thus, a mean transit time of 77 ± 20 years is estimated for the intermediate water in the SCS interior.
Cirrus Horizontal Heterogeneity and 3‐D Radiative Effects on Cloud Optical Property Retrievals From MODIS Near to Thermal Infrared Channels as a Function of Spatial Resolution
Authors: Fauchez T. , Platnick S. , Sourdeval O. , Wang C. , Meyer K. , Cornet C. , Szczap F.
Published: September 2018

To retrieve cloud optical properties, current satellite operational imager algorithms simplify the forward radiative transfer problem by assuming that cloudy pixels are horizontally homogeneous and radiatively independent. This study investigates the effects of cirrus horizontal heterogeneity and 3‐D radiative effects on cloud optical thickness (COT) and ice crystal effective radius (CER) retrievals obtained using simulated nadir near‐infrared/shortwave‐infrared (NIR/SWIR) reflectances at 0.86 and 2.13 μm and thermal infrared (TIR) radiances at 8.5, 11.0, and 12.0 μm, first separately and next using the five wavelengths together. Synthetic cirrus radiation fields are generated using a cirrus 3‐D cloud generator and a 3‐D radiative transfer code. When both cloud 3‐D and heterogeneity effects are considered, the solar reflectance‐based retrievals have the largest errors (up to 10% for COT and 80% for CER, depending on solar angles) for spatial resolutions less than 500–1,000 m, while the TIR‐based retrievals have the largest errors (up to 30% for COT and 50% for CER) above this resolution due to parallel homogeneous approximation bias. Therefore, TIR radiance‐based retrievals are preferable for spatial resolutions equal or higher than ~500 m to 1 km, while NIR/SWIR reflectance‐based retrievals are preferable for coarser spatial resolutions. The combination of NIR/SWIR and TIR measurements performed better together than individually for CER retrieval only for resolutions coarser than 2.5 km because 3‐D effects are negligible at this scale. Thus, the spectral dependence of subpixel cloud horizontal heterogeneity and 3‐D radiative effects has strong consequences when simultaneously using different channels for retrieving cirrus properties.
Radiatively Induced Precipitation Formation in Diamond Dust
Authors: Zeng Xiping
Published: September 2018

Radiative cooling leads to the formation of dew and frost. This process is extended into a numerical model to simulate the ice crystal characteristics of diamond dust. The model replicates the low ice crystal concentration of diamond dust and the precipitation in stationary air. Its results are consistent with the arctic observations that large ice crystals grow while small ones sublimate and partly explain the geographic and seasonal distributions of diamond dust such as the high frequency of diamond dust in the arctic regions and winter. Furthermore, its results show that plate/column‐like ice crystals with radiative cooling grow in expense of quasi‐spherical ice particles, partly explaining the ice crystal shapes observed in diamond dust.
Comment on “Detrital Zircons From the Nanaimo Basin, Vancouver Island, British Columbia: An Independent Test of Late Cretaceous to Cenozoic Northward Translation” by Matthews et al.
Authors: Haggart James W. , Mahoney J. Brian , Ward Peter D.
Published: September 2018

Key Point

Errors in stratigraphic age assignment of Cretaceous detrital zircon samples result in incorrect understanding of ages of geologic units
Real‐Time Control of Urban Headwater Catchments Through Linear Feedback: Performance, Analysis, and Site Selection
Authors: Wong B. P. , Kerkez B.
Published: September 2018

The real‐time control of urban watersheds is now being enabled by a new generation of “smart” and connected technologies. By retrofitting stormwater systems with sensors and valves, it becomes possible to adapt entire watersheds dynamically to individual storms. A catchment‐scale control algorithm is introduced, which abstracts an urban watershed as a linear integrator delay dynamical system, parameterizes it using physical watershed characteristics, and then controls network flows using aLinear Quadratic Regulator. The approach is simulated on a 4‐km2urban headwater catchment in Ann Arbor, Michigan, demonstrating the gains of a stormwater system that can adaptively balance between flood mitigation and flow reduction. We introduce an equivalence analysis and illustrate the performance of the controlled watershed across large events (30‐year storms) to show the uncontrolledpassivewatershed can only match it during smaller events (10‐year storm). For these smaller events, the storage volume of the controlled storage nodes (ponds, basins, and wetlands) could be reduced as much as 50% and still achieve the same performance of the controlled watershed. A controller placement analysis is also carried out, whereby all possible combinations of controlled sites are simulated across a wide spectrum of design storms. We show that the control of every storage node may not be needed in a watershed, but rather that in our case study a small subset (30%) of the overall watershed can be controlled in coordination to achieve outcomes that match a fully controlled system, even when tested across a long‐term rainfall record and under noisy sensor measurements.
Precise Temporal Disaggregation Preserving Marginals and Correlations (DiPMaC) for Stationary and Nonstationary Processes
Authors: Papalexiou Simon Michael , Markonis Yannis , Lombardo Federico , AghaKouchak Amir , Foufoula‐Georgiou Efi
Published: September 2018

Hydroclimatic variables such as precipitation and temperature are often measured or simulated by climate models at coarser spatiotemporal scales than those needed for operational purposes. This has motivated more than half a century of research in developing disaggregation methods that break down coarse‐scale time series into finer scales, with two primary objectives: (a) reproducing the statistical properties of the fine‐scale process and (b) preserving the original coarse‐scale data. Existing methods either preserve a limited number of statistical moments at the fine scale, which is often insufficient and can lead to an unrepresentative approximation of the actual marginal distribution, or are based on a limited number of a priori distributional assumptions, for example, lognormal. Additionally, they are not able to account for potential nonstationarity in the underlying fine‐scale process. Here we introduce a novel disaggregation method, named Disaggregation Preserving Marginals and Correlations (DiPMaC), that is able to disaggregate a coarse‐scale time series to any finer scale, while reproducing the probability distribution and the linear correlation structure of the fine‐scale process. DiPMaC is also generalized for arbitrary nonstationary scenarios to reproduce time varying marginals. Additionally, we introduce a computationally efficient algorithm, based on Bernoulli trials, to optimize the disaggregation procedure and guarantee preservation of the coarse‐scale values. We focus on temporal disaggregation and demonstrate the method by disaggregating monthly precipitation to hourly, and time series with trends (e.g., climate model projections), while we show its potential to disaggregate based on general nonstationary scenarios. The example applications demonstrate the performance and robustness of DiPMaC.
Dietary Gluten Intake and Risk of Microscopic Colitis Among US Women without Celiac Disease: A Prospective Cohort Study
Authors: Liu Po-Hong , Lebwohl Benjamin , Burke Kristin E. , Ivey Kerry L. , Ananthakrishnan Ashwin N. , Lochhead Paul , Olen Ola , Ludvigsson Jonas F. , Richter James M. , Chan Andrew T. , Khalili Hamed
Published: September 2018

OBJECTIVE:

Microscopic colitis is a common cause of chronic watery diarrhea among the elderly. Although the prevalence of celiac disease appears to be higher in patients with microscopic colitis, the relationship between dietary gluten intake and risk of microscopic colitis among individuals without celiac disease has not been explored.

METHODS:

We conducted a prospective study of 160,744 US women without celiac disease enrolled in the Nurses’ Health Study (NHS) and the NHSII. Dietary gluten intake was estimated using validated food frequency questionnaires every 4 years. Microscopic colitis was confirmed through medical records review. We used Cox proportional hazard modeling to estimate the multivariable-adjusted hazard ratio (HR) and 95% confidence interval (CI).

RESULTS:

We documented 219 incident cases of microscopic colitis over more than 20 years of follow-up encompassing 3,716,718 person-years (crude incidence rate: 5.9/100,000 person-years) in NHS and NHSII. Dietary gluten intake was not associated with risk of microscopic colitis (P
trend = 0.88). Compared to individuals in the lowest quintile of energy-adjusted gluten intake, the adjusted HR of microscopic colitis was 1.18 (95% CI: 0.77–1.78) for the middle quintile and 1.03 (95% CI: 0.67–1.58) for the highest quintile. Additional adjustment for primary dietary sources of gluten including refined and whole grains did not materially alter the effect estimates (All P
trend ≥ 0.69). The null association did not differ according to lymphocytic or collagenous subtypes (P
heterogeneity = 0.72) and was not modified by age, smoking status, or body mass index (All P
interaction ≥ 0.17).

CONCLUSIONS:

Dietary gluten intake during adulthood was not associated with risk of microscopic colitis among women without celiac disease.