bluuebunny/crossref_metadata_2025_split huggingface dataset:
Principle of the Helical and Nonhelical Dynamo and the α Effect in a Field Structure Model
Authors: Park Kiwan 
Published: February 2019

Abstract
We demonstrate the conversion process of helical (nonhelical) kinetic energy into magnetic energy using a field-structure model based on the magnetic induction equation. This approach aims to explain the generation, transport, and conservation of magnetic helicity dependent on a forcing method such as kinetic or magnetic forcing. When a system is driven by helical kinetic or magnetic energy, two kinds of magnetic helicities with opposite signs are induced. Then, asymmetric competing processes between them determine the dominant magnetic helicity. Also, the model shows that the conservation of magnetic helicity is related to a common current density and antiparallel magnetic fields in the large- and small-scale regimes. In addition to the intuitive method, we suggest an analytical method to find the α and β coefficients using temporally evolving large-scale magnetic energy and magnetic helicity. The method implies that the α effect and its quenching are generally consistent with the conventional theory. However, the β coefficient implies that the role of kinetic energy in a dynamo may be somewhat different from our conventional understanding. We also show how the kinetic energy near the viscous scale can suppress the dynamo process when the magnetic Prandtl number (Pr
M
) is small. We verify this using simulation results. Finally, using the α
2 effect and differential rotation effect, we suggest a solar dynamo model that explains the periodic magnetic evolution in the Sun.
No Stripped Companion Material in the Nebular Spectrum of the “Two-Component” Type Ia Supernova ASASSN-18bt
Authors: Tucker M. A. , Shappee B. J. , Wisniewski J. P. 
Published: February 2019

Abstract
We analyze a Keck I/Low Resolution Imager and Spectrograph nebular spectrum taken 268 days after B-band maximum of ASASSN-18bt (SN 2018oh), a Type Ia supernova observed by K2 at the time of explosion. ASASSN-18bt exhibited a two-component rise to peak brightness, possibly the signature of an interaction between the supernova ejecta and a large (≳20 R
⊙) nearby, non-degenerate companion. We search for emission signatures of stripped material from a non-degenerate companion in the nebular spectrum and find no evidence for any unbound material. We place an upper limit of <0.006 M
⊙ on the amount of stripped/ablated H-rich material that could go undetected in our spectrum, effectively ruling out all hydrogen-rich donor stars. Additionally, we place a more tentative upper limit on He i emission in the observed spectrum of ≲0.02 M
⊙ which also rules out helium star companions. Our deep limits rule out a non-degenerate companion as the explanation for the early-time feature in ASASSN-18bt.
Electron-scale Vertical Current Sheets in a Bursty Bulk Flow in the Terrestrial Magnetotail
Authors: Zhou M. , Huang J. , Man H. Y. , Deng X. H. , Zhong Z. H. , Russell C. T. , Paterson W. R. , Giles B. L. , Lindqvist P.-A. , Khotyaintsev Y. V. , Burch J. L. 
Published: February 2019

Abstract
We report Magnetospheric Multiscale observations of multiple vertical current sheets (CSs) in a bursty bulk flow in the near-Earth magnetotail. Two of the CSs were fine structures of a dipolarization front (DF) at the leading edge of the flow. The other CSs were a few Earth radii tailward of the DF; that is, in the wake of the DF. Some of these vertical CSs were a few electron inertial lengths thick and were converting energy from magnetic field to plasma. The currents of the CSs in the DF wake were carried by electrons that formed flow shear layers. These electron-scale CSs were probably formed during the turbulent evolution of the bursty bulk flow and are important for energy conversion associated with fast flows.
Seasonal Changes in Titan’s Upper Haze Resulting from Saturn’s Eccentric Orbit
Authors: Larson E. J. L. 
Published: February 2019

Abstract
Organic aerosols are produced high in the atmosphere of Titan by complex photochemical pathways starting from the dissociation of CH4 by solar ultraviolet (UV) and N2 by energetic particles. An end product of this photochemistry is the organic haze enshrouding Titan. The solar flux at Titan varies by about 20% between periapsis and apoapsis, thus we expect the dissociation of CH4 and the total production of aerosols to have a similar seasonal dependence. The seasonal cycle in the haze production due to Saturn’s orbital eccentricity is complicated by seasonal changes in dynamics and aerosol particle size due to Saturn’s 27° obliquity. A 3D Titan general circulation model with fully coupled aerosol microphysics, the Titan Community Atmospheres Model, simulates the aerosol haze with and without aerosol production as a function of solar UV. Both simulations display an equatorial seasonal cycle in the haze above about 340 km; however, this cycle is amplified by a factor of 2 in the simulation with production as a function of solar UV. We compare the simulations with published estimates of haze extinction in the upper atmosphere. Current observations of the haze extinction at 400 km cannot distinguish between the two simulations, highlighting the difficulties that complicated dynamics in the upper atmosphere pose for trend detection.
Avalanches en moyenne montagne : des représentations à l’occultation du risque
Authors: Florie Giacona , Brice Martin , Nicolas Eckert 
Published: February 2019

En France, en moyenne montagne, le risque d’avalanche apparaît occulté alors que l’aléa avalanche est pourtant bien présent, et les enjeux réels. Cet article montre que ce paradoxe résulte de représentations qui dépassent le seul phénomène physique. La prégnance du modèle alpin (les Alpes constituant le modèle-type de la montagne) ainsi que la construction de la notion moyenne montagne par opposition à la haute montagne conduisent à faire de la moyenne montagne un espace distinct au caractère « tendrement montagneux »1. Dans ce contexte, l’ancrage territorial en haute montagne de la figure de l’avalanche, et plus largement du risque, se retrouve jusqu’aux acteurs scientifiques et institutionnels. Il se traduit, dans le système de gestion du risque d’avalanche français, par l’organisation de deux sous-systèmes distincts, celui dédié à la moyenne montagne se distinguant par l’absence de nombre d’outils et d’acteurs spécifiques. Finalement, les caractéristiques et les images associées aux objets phénomène avalanche et montagne concourent, implicitement ou explicitement, à occulter le risque en moyenne montagne, et donc à l’absence de fabrication du problème avalanche dans cet espace. Le cas archétypal du Massif vosgien permet d’illustrer le propos.
Processus morphodynamiques et sédimentaires dans les mangroves en érosion de Mayotte, océan Indien
Authors: Jeanson Matthieu , Dolique Franck , Anthony Edward J. 
Published: February 2019

L’île de Mayotte est caractérisée par un littoral très diversifié comprenant de nombreuses mangroves à l’intérieur d’un vaste complexe récifo-lagonaire. Plusieurs de ces mangroves sont en forte régression avec des implications géomorphologiques significatives. Des expérimentations de terrain ont été conduites pour quantifier les changements morphologiques et pour comprendre les processus hydro-sédimentaires en action. Les mesures hydrodynamiques ont montré le rôle majeur de la répartition des mangroves sur l’atténuation de l’énergie des vagues. Dans les secteurs végétalisés, l’atténuation de l’énergie des vagues atteint plus de 90 % contre 35 % dans les secteurs dénués de palétuviers. Les observations morphologiques ont montré que l’érosion et le remaniement des sédiments sablo-vaseux des mangroves assurent le développement de placages et de barres sableuses sur l’estran. Ces sédiments sableux migrent progressivement vers le haut de l’estran, ce qui conduit à l’aggradation des cordons sableux localisés en arrière des mangroves. L’élévation continue des cordons sableux mène à l’enfouissement des systèmes racinaires et à l’asphyxie puis à la mort des palétuviers. Cette étude met en lumière le rôle de la mangrove qui va exercer un contrôle significatif sur l’activation des processus géomorphologiques et la sédimentation intertidale. Ces processus reflètent parfaitement la notion d’ajustements biogéomorphologiques inhérente à ces systèmes.
Improving urban metabolism through agriculture : an approach to ecosystem services qualitative assessment in Rome
Authors: Cartiaux Nicolas , Mazzocchi Giampiero , Marino Davide , Jijakli Haissam 
Published: February 2019

Cet article présente le cas de l'agriculture péri-et urbaine dans le contexte de la municipalité de Rome soulignant, en particulier, sa contribution aux services écosystémiques fournis à la population urbaine. Ces différents cas d'agriculture participent à la résilience de la ville marquant et influençant le fonctionnement du paysage agricole de la ville. Parmi les différents outils mis en place par la municipalité, nous avons pris en considération les prêts accordés aux jeunes agriculteurs du projet « terre publiques » lancé en 2013 afin de participer au développement de fermes multifonctionnelles visant à la fois à la protection et à la restauration du système agricole. Malgré la demande et volonté d'accès aux terres publiques, aucun réelle politique paysagère ou cadre de planification ont été développées faisant courir le risque de voir ces différentes initiatives sporadiques. Les résultats ont montré que ces fermes multifonctionnelles fournissent un large panel de bénéfices influençant et régénérant le voisinage et que les activités agricoles maintiennent la fonction de sol et fournissent des services écosystémiques essentiels pour la société.
Surface erythemal UV irradiance in the continental United States derived from ground-based and OMI observations: quality assessment, trend analysis and sampling issues
Authors: Zhang Huanxin , Wang Jun , Castro García Lorena , Zeng Jing , Dennhardt Connor , Liu Yang , Krotkov Nickolay A. 
Published: February 2019

Abstract. Surface full-sky erythemal dose rate (EDR) from the Ozone Monitoring
Instrument (OMI) at both satellite overpass time and local noon time is
evaluated against ground measurements at 31 sites from the US Department of
Agriculture's (USDA) UV-B Monitoring and Research Program (UVMRP) over the period of 2005–2017. We find that both OMI
overpass and solar noon time EDR are highly correlated with the measured
counterparts (with a linear correlation coefficient of 0.90 and 0.88,
respectively). Although the comparison statistics are improved with a longer
time window (0.5–1.0 h) for pairing surface and OMI measurements, both OMI
overpass and local noon time EDRs have 7 % overestimation that is larger
than 6 % uncertainty in the ground measurements and show different levels
of dependence on solar zenith angle (SZA) and to lesser extent on cloud optical
depth. The ratio of EDR between local noon and OMI overpass time is often
(95 % in frequency) larger than 1 with a mean of 1.18 in the OMI product;
in contrast, the same ratio from surface observation is normally distributed with 22 %
of the times less than 1 and a mean of 1.38. This contrast in
part reflects the deficiency in the OMI surface UV algorithm that assumes
constant atmospheric conditions between overpass and noon time. The
probability density functions (PDFs) for both OMI and ground measurements of
noontime EDR are in statistically significant agreement, showing dual peaks
at ∼20 and ∼200 mW m−2, respectively; the latter is lower
than 220 mW m−2, the value at which the PDF of daily EDR from ground measurements
peaks, and this difference indicates that the largest EDR value for a given
day may not often occur at local noon. Lastly, statistically significant
positive trends of EDR are found in the northeastern US in OMI data, but
opposite trends are found within ground-based data (regardless of sampling
for either noontime or daily averages). While positive trends are
consistently found between OMI and surface data for EDR over the southern
Great Plains (Texas and Oklahoma), their values are within the uncertainty of
ground measurements. Overall, no scientifically sound trends can be found
among OMI data for aerosol total and absorbing optical depth, cloud optical
depth and total ozone to explain coherently the surface UV trends revealed
either by OMI or ground-based estimates; these data also cannot reconcile trend
differences between the two estimates (of EDR from OMI and surface observations). Future geostationary satellites with
better spatiotemporal resolution data should help overcome spatiotemporal
sampling issues inherent in OMI data products and therefore improve the
estimates of surface UV flux and EDR from space.
Stochastic ensemble climate forecast with an analogue model
Authors: Yiou Pascal , Déandréis Céline 
Published: February 2019

Abstract. This paper presents a system to
perform large-ensemble climate stochastic forecasts. The system is based on
random analogue sampling of sea-level pressure data from the NCEP reanalysis.
It is tested to forecast a North Atlantic Oscillation (NAO) index and the
daily average temperature in five European stations. We simulated 100-member
ensembles of averages over lead times from 5 days to 80 days in a hindcast
mode, i.e., from a meteorological to a seasonal forecast. We tested the
hindcast simulations with the usual forecast skill scores (CRPS or
correlation) against persistence and climatology. We find significantly
positive skill scores for all timescales. Although this model cannot
outperform numerical weather prediction, it presents an interesting benchmark
that could complement climatology or persistence forecast.
ARBORIZAÇÃO EM PRAÇAS NO MUNICÍPIO DE JATAÍ, GO, BRASIL
Authors: Amaral Érica Virgínia , Guilherme Frederico Augusto Guimarães 
Published: February 2019

Arborização urbana refere-se ao conjunto de árvores que compõem o paisagismo de uma cidade, plantadas em áreas verdes, como em parques e praças, destinadas ao incentivo da vida comunitária. A cidade de Jataí, localizada no Sudoeste do Estado de Goiás, destaca-se por seus lagos e parques, porém é notória a falta de planejamento em áreas públicas. Assim, o estudo teve o objetivo de analisar a arborização de praças da cidade, por meio de um estudo quali-quantitativo das espécies arbóreas. As 14 praças escolhidas foram as maiores e mais frequentadas pela população. Todas as árvores adultas foramcontabilizadas, além das mudas de árvores recém-plantadas. Foram registrados 1030 indivíduos, pertencentes a 33 famílias botânicas e 81 espécies. As espécies mais frequentes foram Syagrus oleracea (Gueiroba) com 430 indivíduos encontrados em 12 praças e Poincianella pluviosa (Sibipiruna) com 146 indivíduos em 11 praças. Algumas praças apresentaram boa variedade de espécies, porém seis delas não apresentaram mais do que dez espécies. Aproximadamente 27% das árvores corresponderam a indivíduos imaturos ejovens, demonstrando uma recente preocupação do poder público com a arborização.
USO DE ÁREAS VERDES EM MOGI MIRIM: PREFERÊNCIA DA POPULAÇÃO
Authors: Marques Valeska Ribeiro , Silva Luiz Felipe , Santos Gleise Bertolazi , Gamarra Nancy Rios 
Published: February 2019

As áreas verdes melhoram a qualidade de vida da população, podem diminuir extremos de temperatura, atenuar ruído, reter poeira, aumentar a área permeável urbana, oferecer um espaço agradável para prática de atividade física e o convívio social, entre outros inúmeros benefícios. Trata-se de um espaço que se comporta como um promotor de saúde da população. O objetivo deste trabalho foi levantar quais áreas verdes são utilizadas na cidade de Mogi Mirim, estado de São Paulo. A metodologia utilizada foi uma investigação epidemiológica observacional com característica de um estudo transversal de base populacional. Foram entrevistados, por amostragem aleatória, 262 pessoas. Dos entrevistados, 47% frequentam as áreas verdes, no mínimo uma vez por semana, para o convívio social (30,2%), atividade física (29,4%), lazer com crianças (21,8%) e passear com cão (9,2%). As praças são as áreas mais procuradas. Destaca-se o Complexo Lavapés, frequentado por 23% dos entrevistados, dos quais 90% residem a até três quilômetros da área verde. Este estudo é um recurso relevante, pouco encontrado na literatura científica nacional, na medida em que procura estudar as relações entre área verde e saúde e assim contribuir para a adoção destes locais, como prática essencial de promoção à saúde.
Annotated review of Cryptocephalinae (Clytrini), Synetinae and part of Galerucinae (Coleoptera, Chrysomelidae) described by Carl Peter Thunberg
Authors: Bezděk Jan 
Published: February 2019

The taxa of Cryptocephalinae (Clytrini), Synetinae and part of Galerucinae introduced by Carl Peter Thunberg are reviewed based on the examination of primary type specimens deposited in the Museum of Evolution, Uppsala University. The following taxonomic changes are proposed: Coptocephala unifasciata unifasciata (Scopoli, 1763) = Cryptocephalus melanocephalus Thunberg, 1787 syn. nov.; Melitonoma decemnotata (Thunberg, 1787) comb. nov. (from Cryptocephalus Geoffroy, 1762); Miopristis flexuosa (Thunberg, 1821) = Miopristis namaquensis Medvedev, 1993 syn. nov.; Protoclytra (Lacordairella) taeniata (Thunberg, 1821) comb. nov. (from Camptolenes Chevrolat, 1836) = Camptolenes fastuosa (Lacordaire, 1848) syn. nov.; Smeia undata (Thunberg, 1821) comb. nov. (from Miopristis Lacordaire, 1848) = Smeia virginea (Lacordaire, 1848) syn. nov. = Melitonoma pictipennis Jacoby, 1898 syn. nov.; Teinocera catenata (Thunberg, 1821) comb. nov. (from Miopristis) = Teinocera subclathrata (Lacordaire, 1848) syn. nov.; Exosoma lusitanica (Linnaeus, 1767) = Crioceris haemorrhoa Thunberg, 1827 syn. nov.; Megalognatha festiva (Fabricius, 1781) = Crioceris virens Thunberg, 1827 syn. nov.; Monolepta bioculata (Fabricius, 1781) = Cryptocephalus bioculatus Thunberg, 1827 syn. nov.; Monolepta melanogaster (Wiedemann, 1823) = Cryptocephalus capensis Thunberg, 1827 syn. nov.; Palaeophylia tricolor (Fabricius, 1781) = Crioceris tetrapuncta Thunberg, 1787 syn. nov. = Crioceris dimidiata Thunberg, 1827 syn. nov. Lectotypes are designated for Cryptocephalus bioculatus Thunberg, 1827 and Crioceris dimidiata Thunberg, 1827. Melitonoma decemnotata comb. nov. is redescribed. Labidostomis insidiosa Péringuey, 1888 is resurrected from synonymy with Teinocera catenata comb. nov. and provisionally placed as a valid species in the genus Miopristis Lacordaire, 1848. Crioceris betulina Thunberg, 1787 is proposed as nomen oblitum for Syneta betulae (Fabricius, 1792) (nomen protectum). Colour photographs of the type specimens of all taxa are provided.
Planting orientation of Portulacaria afra cuttings for thicket restoration: vertical versus horizontal
Authors: Ragimana Mutakusi B , Potts Alastair J 
Published: February 2019

Aim. The re-establishment of Portulacaria afra in the landscape-scale Subtropical Thicket Restoration Programme has exclusively used vertically-orientated truncheons (i.e. large cuttings with the main stem planted 10-20 cm into the ground). Despite the planting of millions of truncheons, the rates of survival, growth and restoration are low. This may be driven by browsing pressure and/or drought conditions during the truncheon establishment phase. Here we conduct a common garden experiment to explore the establishment of horizontal versus vertically orientated truncheons. Horizontal truncheons have their main stem buried in the soil and only a few side branches exposed above ground — these truncheons may experience reduced water stress. Here we compared the levels of water stress during the establishment phase of truncheons with different orientation.
Location. Eastern Cape, South Africa.
Methods. Our experiment involved three planting treatments for truncheons: vertical orientation, horizontal orientation, and horizontal orientation with exposed side branches clipped. Truncheons were grown for two months and plants were well-watered. On two occasions during the experiment, photosynthetic efficiency was measured on all plants to ascertain levels of plant stress. After the experiment, the root, stem and leaf dry mass were recorded for each replicate, as well as leaf moisture.
Results. The root mass proportion (of the total plant) was not significantly different among treatments. Despite this, leaf-level photosynthetic efficiency was recorded as significantly lower in vertical truncheons versus horizontal truncheons.
Main conclusions. Smaller horizontally-orientated truncheons do not grow roots at a faster rate (relative to their total size) than the larger vertically-orientated truncheons that have more leaf material to support. Nonetheless, under well-watered conditions, the larger truncheons experienced stress evidenced by lowered leaf photosynthetic efficiency values. Thus, we suggest that horizontal buried truncheons may have a higher likelihood of survival under seasonal drought-stress conditions. It remains to be tested whether horizontally-orientated truncheons (with less above-ground biomass) experience lower rates of herbivory than the standard vertical cuttings.
Compliance with Use of Micronutrient Powder among Caregivers of Children Aged 6-23 Months in a District of a State in North East Nigeria
Authors: Adejugbagbe Adewale M. , Fatiregun Akinola A. , Isere Elvis E. , Adewale Olubunmi Oki 
Published: February 2019

Aims: To assess the knowledge and perception about micronutrient powder (MNP) use, compliance with use of the product, and determine factors influencing compliance to continual use of MNP for food fortification among caregivers of children aged 6-23 months in Konduga LGA, Borno State, Nigeria.
Study Design: A cross-sectional study was conducted.
Place and Duration of Study: The study was conducted in Konduga LGA, Borno State Nigeria in August 2018.
Methodology: A total of 218 caregivers of children aged 6-23 months were selected using a multistage sampling technique. A semi-structured interviewer-administered questionnaire was used to interview respondents on socio-demographic characteristics, knowledge about complementary feeding, perception about MNP use and compliance with use of MNP for food fortification. Data were analyzed using descriptive statistics, Chi-square test and logistic regression, with the level of significance set at 0.05.
Results: Respondents were female with 111 (50.9%) below 30 years of age (mean age: 29.3±8.0). Twenty-four (11%) of the respondents have good knowledge of complementary feeding and 77 (35.3%) have a good perception of the use of MNP. Almost two-thirds [135 (61.9%)] of the respondents used MNP. Factors that influenced respondents’ compliance with use of MNP include; being <30 years of age (P= .04), having a spouse with formal education (P= .003) and is not working (P= .013) and having good knowledge of complementary feeding (P= .01). Among these factors, having a spouse that is not working determined compliance with use of MNP (AOR=3.3, 95% CI= 1.6-7.5).
Conclusion: Although compliance with use of MNP was above average, however, there is need to improve on Infant and Young Child Feeding (IYCF) counselling focusing on the importance of MNP particularly among the older caregivers and their spouse.