bluuebunny/crossref_metadata_2025 huggingface dataset:
Inverse modeling of pan-Arctic methane emissions at high spatial resolution:
what can we learn from assimilating satellite retrievals and using different
process-based wetland and lake biogeochemical models?
Authors: Tan Zeli , Zhuang Qianlai , Henze Daven K. , Frankenberg Christian , Dlugokencky Ed , Sweeney Colm , Turner Alexander J. , Sasakawa Motoki , Machida Toshinobu
Published: October 2016

Abstract. Understanding methane emissions from the Arctic, a fast-warming carbon reservoir, is important for projecting future changes in the global methane cycle. Here we optimized methane emissions from north of 60° N (pan-Arctic) regions using a nested-grid high-resolution inverse model that assimilates both high-precision surface measurements and column-average SCanning Imaging Absorption spectroMeter for Atmospheric CHartogrphY (SCIAMACHY) satellite retrievals of methane mole fraction. For the first time, methane emissions from lakes were integrated into an atmospheric transport and inversion estimate, together with prior wetland emissions estimated with six biogeochemical models. In our estimates, in 2005, global methane emissions were in the range of 496.4–511.5 Tg yr−1, and pan-Arctic methane emissions were in the range of 11.9–28.5 Tg yr−1. Methane emissions from pan-Arctic wetlands and lakes were 5.5–14.2 and 2.4–14.2 Tg yr−1, respectively. Methane emissions from Siberian wetlands and lakes are the largest and also have the largest uncertainty. Our results indicate that the uncertainty introduced by different wetland models could be much larger than the uncertainty of each inversion. We also show that assimilating satellite retrievals can reduce the uncertainty of the nested-grid inversions. The significance of lake emissions cannot be identified across the pan-Arctic by high-resolution inversions, but it is possible to identify high lake emissions from some specific regions. In contrast to global inversions, high-resolution nested-grid inversions perform better in estimating near-surface methane concentrations.
Assessment of the aerosol optical depths measured by satellite-based
passive remote sensors in the Alberta oil sands region
Authors: Sioris Christopher E. , McLinden Chris A. , Shephard Mark W. , Fioletov Vitali E. , Abboud Ihab
Published: October 2016

Abstract. Several satellite aerosol optical depth (AOD) products are assessed in terms of their data quality in the Alberta oil sands region. The instruments consist of MODIS (Moderate resolution Imaging Spectroradiometer), POLDER (Polarization and Directionality of Earth Reflectances), MISR (Multi-angle Imaging SpectroRadiometer), and AATSR (Advanced Along-Track Scanning Radiometer). The AOD data products are examined in terms of multiplicative and additive biases determined using local AERONET (AEROCAN) stations. Correlation with ground-based data is used to assess whether the satellite-based AODs capture day-to-day, month-to-month, and spatial variability. The ability of the satellite AOD products to capture interannual variability is assessed at Albian Mine and Shell Muskeg River, two neighbouring sites in the northern mining region where a statistically significant positive trend (2002–2015) in PM2.5 mass density exists. An increasing trend of similar amplitude is observed in this northern mining region using some of the satellite AOD products.
Characterization of the Long-term Radiosonde Temperature Biases in the Lower Stratosphere using COSMIC and Metop-A/GRAS Data from 2006 to 2014
Authors: Ho Shu-Peng , Peng Liang , Vömel Holger
Published: October 2016

Abstract. Radiosonde observations (RAOBs) have provided the only long-term global in situ temperature measurements in the troposphere and lower stratosphere since 1958. In this study, we use consistently reprocessed Global Positioning System (GPS) radio occultation (RO) temperature data derived from COSMIC and Metop-A/GRAS missions from 2006 to 2014 to characterize the inter-seasonal and inter-annual variability of temperature biases in the lower stratosphere for different sensor types. The results show that the RAOB temperature biases for different RAOB sensor types are mainly owing to i) uncorrected solar zenith angle dependent errors, and ii) change of radiation correction. The mean daytime temperature difference (ΔT) for Vaisala RS92 is equal to 0.18 K in Australia, 0.20 K in Germany, 0.10 K in Canada, 0.13 K in England, and 0.33 K in Brazil. The mean daytime ΔT is equal to −0.06 K for Sippican, 0.71 K for VIZ-B2, 0.66 K for AVK-MRZ, and 0.18 K for Shanghai. The daytime trend of anomalies for Vaisala RS92 and RO temperature at 50 hPa is equal to 0.00 K/5 yrs over United States, −0.02 K/5 yrs over Germany, 0.17 K/5 yrs over Australia, 0.23 K/5 yrs over Canada, 0.26 K/5 yrs over England, and 0.12 K/5 yrs over Brazil, respectively. Although there still exist uncertainties for Vaisala RS92 temperature measurements over different geographical locations, the global trend of temperature anomaly between Vaisala RS92 and RO from June 2006 to April 2014 is within +/−0.09 K/5 yrs globally. Comparing with Vaisala RS80, Vaisala RS90 and sondes from other manufacturers, the Vaisala RS92 seems to provide the best RAOB temperature measurements, which can potentially be used to construct long term temperature CDRs. Results from this study also demonstrate the feasibility to use RO data to correct RAOB temperature biases for different sensor types.
Introduction: The Responsibility of Awkwardness
Authors: Bragg Nicolette
Published: October 2016

The thought of the limit has in its genetics the questioning of time and place. The essays in this collection, African Thinking and/at Its Limits, demonstrate this essential interrogation (how time and space both belong to a certain critical modality); their address of (and at) the limits of African thinking is inevitably also one that presents us with the limitedness of temporal and spatial understandings. For the limit signals the very reach(es) of time and place, and enables the possibility of territory, control, management, and measure – possibilities that can seem at once infinite and inordinately restricted. Possibility, the very provocation of the limit, can itself be formulated in terms of time and place—What can (yet) be done? Where is it possible to go? Where do we from here? The limit signifies both expiration, the farthest point a thinking can take one, and consolidation, the demarcation and establishment of a territory. These questions of time and place are, as such and for these very reasons, bound up in any thinking of Africa. This, too, is clear from the issues addressed by the contributions to this collection, not the least of which are the very historicity of the concepts commonly used to assess or explain state crisis, the hangovers of colonial paradigms, and how to think, address, and analyze the crisis of the postcolony.
Between Earth and Sky
Authors: Martinon Jean-Paul
Published: October 2016

Africa. Who are you?I deliberately don’t say here, “What are you?” As we know, the interrogative pronoun “what” is an attempt to grab the essence of something. As Heidegger says: “whatness [Wassein], comprises what one commonly calls… the idea or mental representation by means of which we propose to… grasp what a thing is.” As such, questions starting with the interrogative pronoun “what” are eminently violent because they reduce the object of inquiry to a thing that can be held in one’s hand; that can make sense as a totality; that can be conceptualized with one idea. The history of philosophy— from Plato to Augustine, from Descartes to Lenin, all the way to Kwame Nkrumah, for example—is littered with the question “What…?”; with these violent attempts at grabbing the essence of something. Africa’s history is also littered with these attempts at reducing a continent to an essence or concept. These attempts are absurdly grandiose (pinning down “the idea” of Africa, for example) and ridiculously small (analyzing the minutiae of life in a village, for example). In all cases, they try to envision Africa as an object to be possessed by any means and I know that we can’t carry on doing that..
Frantz Fanon: Philosophy, Praxis, and the Occult Zone
Authors: Pithouse Richard
Published: October 2016

In 2011, Achille Mbembe asserted that “the human has consistently taken on the form of waste within the peculiar trajectory race and capitalism espoused in South Africa.” He added that the end of apartheid had shifted rather than undone the lines of exclusion and dispute. Since the massacre on the platinum mines in 2012 it has become widely accepted that the state is resorting to repressive measures to enforce these lines and contain the dispute that they occasion. With notable exceptions academic philosophy, and theory more broadly, has offered remarkably little illumination of the widening distance between the promise of national liberation and democracy and the often bitter realities of contemporary South Africa. [i] Achille Mbembe ‘Democracy as Community Life’ Johannesburg Workshop in Theory & Criticism, 2011 http://jwtc.org.za/volume_4/achille_mbembe.htm
Cardiac manifestation of the huge pulmonary mass simulating ST-elevation myocardial infarction
Authors: Wassef Nancy , Dorrington Sarah , Pulikal George
Published: October 2016

A 77-year-old Caucasian female presented with central chest pain and an electrocardiogram showing anterior and inferior ST segment elevation. The patient had discrepancy of the blood pressure measurement and unequal radial pulses of the upper limbs. Urgent CT thorax and aorta showed no evidence of aortic dissection, but it showed a large mass in the left lung lower lobe, which involved the adjacent structures including the left ventricular. The patient refused to have a bronchoscopy or any further investigations and was discharged to the community with palliative care support.
An Empirical Study for Work Stresses in Jordanian Tourism Companies
Authors: Khasawneh Mohammad Shabib
Published: October 2016

This study focused on measuring the level of job stresses felt by employees in Jordanian tourism companies in Amman; based on the knowledge of these stresses and showing the impact of these sources to the total job stress level and studying the differences in the level of feelings of companies personnel depending on their different demographic characteristics. 242 questionnaires were analyzed and distributed randomly on a sample of companies. The findings revealed that the most employees in the study sample feel stressed at work and that the job stresses which are caused by the organization was one of the most influential sources of raising the level of job stress.
Nutritional Value of Crisphead ‘Iceberg’ and Romaine Lettuces (Lactuca sativa L.)
Authors: Kim Moo Jung , Moon Youyoun , Kopsell Dean A. , Park Suejin , Tou Janet C. , Waterland Nicole L.
Published: October 2016

Lettuce (Lactuca sativa L.) is one of the most popular vegetables worldwide, but is often viewed as low in nutritional value. However, lettuce contains health-promoting nutrients and biosynthesis of such phytochemicals varies depending on cultivar, leaf color and growing conditions. Studies of such parameters on the nutritional value have not been conclusive because the lettuce samples were collected from heterogeneous growing conditions and/or various developmental stages. In our study nutritional composition was evaluated in the two most popular lettuce types in Western diets, romaine and crisphead ‘Iceberg’, with red or green leaves grown under uniform cultivating conditions and harvested at the same developmental stage. In the investigated lettuce cultivars, insoluble fiber content was higher (P ≤ 0.05) in romaine than crisphead lettuces. Alpha-linolenic acid (omega-3 polyunsaturated fatty acid) was the predominant fatty acid and was higher in romaine than crisphead. Iron and bone health-promoting minerals (Ca, Mg and Mn) were significantly higher (P ≤ 0.001) in romaine. The content of Beta-carotene and lutein in romaine (668.3 ug g-1 dry weight) was ~45% higher than in crisphead (457.3 ug g-1dry weight). For leaf color comparison, red cultivars provided higher amount of minerals (Ca, P, Mn and K), total carotenoids, total anthocyanins and phenolics than green cultivars. Based on our study results, romaine was generally higher in nutrients analyzed, especially red romaine contained significantly higher amount of total carotenoids, total anthocyanins and phenolics. Therefore, romaine type lettuces with red rather than green leaves may offer a better nutritional choice.
Response of Maize (Zea mays L.) Secondary Growth Parameters to Conservation Agriculture and Conventional Tillage Systems in Zimbabwe
Authors: Hlatywayo Regina , Mhlanga Blessing , Mazarura Upenyu , Mupangwa Walter , Thierfelder Christian
Published: October 2016

Previous, research focused mainly on the effects of conservation agriculture (CA) and conventional practices (CP) on crop yield mostly. A study was conducted at five sites in Zimbabwe from 2012 to 2014 to investigate effects of CA and CP practices on emergence, chlorophyll content, early vigour and grain yield of different maize varieties using 12 hybrids and 4 open pollinated varieties (OPVs). The experiment was laid as a 4 × 4 alpha lattice design with three replications. Emergence was higher under CA (75%) at University of Zimbabwe (UZ) in 2012/13 and Domboshawa Training Centre (DTC) (67%) compared to CP (71% and 39% respectively). Lower early plant vigour was observed under CA compared to CP at most sites. CA had lower leaf chlorophyll content during the early crop growth stages compared to CP. However, at some instances, CA had higher leaf chlorophyll content (45 units) than CP (35 units) at 78 days after sowing in Zimuto 2012/13. For maize yield, CA outperformed CP on a sandy loamy soil (3050 kg ha-1 vs 2656 kg ha-1) and clay soil (4937 kg ha-1 vs 4274 kg ha-1). However, on a sandy soil, CP outperformed CA (1764 vs 1313 kg ha-1). Our results suggest that tillage effects on early maize plant vigor, leaf chlorophyll content and the final yield can be site and season specific. Furthermore, a delay of nutrient release for plant uptake under CA systems was found and potentially implies investigations of new fertilization strategies for such cropping systems.
Combining Ability Analysis of Blast Disease Resistance and Agronomic Traits in Finger Millet [Eleusine coracana (L.) Gaertn]
Authors: Owere Lawrence , Tongoona Pangirayi , Derera John , Wanyera Nelson
Published: October 2016

Blast disease is the most important biotic constraint to finger millet production. Therefore disease resistant varieties are required. However, there is limited information on combining ability for resistance and indeed other agronomic traits of the germplasm in Uganda. This study was carried out to estimate the combining ability and gene effects controlling blast disease resistance and selected agronomic traits in finger millet. Thirty six crosses were generated from a 9 × 9 half diallel mating design. The seed from the 36 F1 crosses were advanced by selfing and the F2 families and their parents were evaluated in three replications. General combining ability (GCA) for head blast resistance and the other agronomic traits were all highly significant (p ≤ 0.01), whereas specific combining ability (SCA) was highly significant for all traits except grain yield and grain mass head-1. On partitioning the mean sum of squares, the GCA values ranged from 31.65% to 53.05% for head blast incidence and severity respectively, and 36.18% to 77.22% for the other agronomic traits measured. Additive gene effects were found to be predominant for head blast severity, days to 50% flowering, grain yield, number of productive tillers plant-1, grain mass head-1, plant height and panicle length. Non-additive gene action was predominant for number of fingers head-1, finger width and panicle width. The parents which contributed towards high yield were Seremi 2, Achaki, Otunduru, Bulo and Amumwari. Generally, highly significant additive gene action implied that progress would be made through selection whereas non-additive gene action could slow selection progress and indicated selection in the later generations.
Knowledge and Adoption of Conservation Agriculture Technologies by the Farming Community in Different Agro-Climatic Zones of Tamilnadu State in India
Authors: Ramasubramaniyan M. R. , Vasanthakumar J. , Hansra B. S.
Published: October 2016

Tamilnadu State in India is one of the earlier beneficiaries of Green Revolution which contributed to multifold increase in agricultural productivity. Though the State has been progressive, it has also experienced the ill effects of over exploitation of natural resources through intensive agriculture. There is an urgent need to shift its focus from over exploitative intensive farming to more sustainable farming with optimal use of resources without causing imbalances. Conservation Agriculture (CA) offers potential solution which not only enhances the productivity but also maintains the environmental safety and ecological sustainability. With this at the backdrop, the present study was conducted during 2013-2014 in all the seven agro-climatic zones of Tamilnadu State in India covering 350 respondents to understand the knowledge and adoption levels of Conservation Agriculture among the farming community in the State. Three Conservation agricultural technologies namely, Minimum Tillage, Crop Rotation and Permanent Soil Cover were identified. Knowledge of the farmers about these technologies and their adoption by the farmers were studied. As regards the awareness and knowledge level of respondents majority of them do not have knowledge on minimum tillage (72.6%) and permanent soil cover (75.1%) but a vast majority is knowledgeable on crop rotation (71.1%). Farmer characteristics such as age, educational status and innovativeness of farmers played a significant impact on the knowledge levels of CA whereas number of years of experience in farming and land holding pattern did not have significant influence on the knowledge levels of farmers on CA. Among the knowledgeable farmers only 11.5% of farmers adopted minimum tillage, 27.6% of farmers adopted permanent soil cover and 78% adopted crop rotation. None of the farmers adopted CA as a whole comprising all the three components.
Evaluation of Serenade Max to Control Fruit Rot of Grapes
Authors: Thomidis T. , Pantazis S. , Konstantinoudis K.
Published: October 2016

The effectiveness of the biopesticide Serenade Max to control fruit rot in grape was investigated. The experiments were conducted in commercial vineyard (cv Xinomavro Naousa). The results showed that this product was relatively effective to control fruit rots on grapes. No significant difference was observed between Serenade Max and Switch25/37.5 WG in both years of experiment. It was found that the fungus Botrytis cinerea commonly caused fruit rots (at a percentage of 96%) on the control grape fruits.

Generally, Serenade Max could be an alternative method against fruit rots of grape in biological fruit production system.
Reviewer Acknowledgements for Journal of Agricultural Science, Vol. 8, No. 11
Authors: Brown Anne
Published: October 2016

Reviewer acknowledgements for Journal of Agricultural Science, Vol. 8, No. 11, 2016.
Effects of Fertilizer Levels on the Absorption, Translocation, and Distribution of Phosphorus and Potassium in Rice Cultivars with Different Nitrogen-Use Efficiencies
Authors: Sun Yongjian , Sun Yuanyuan , Xu Hui , Wang Chunyu , Yang Zhiyuan , Li Na , Yan Fengjun , Li Yinghong , Wang Haiyue , Ma Jun
Published: October 2016

The fertilizer management and the selection of rice cultivars play a vital role in rice production to maximize yield and minimize fertilizer cost. Many researches have elucidated the combined increase of nitrogen (N) accumulation and N use efficiency (NUE) in different rice genotypes, however, the accumulation, translocation, distribution of phosphorus (P) and potassium (K), and the correlation of N, P and K absorption characteristics and their relationships with grain yield in rice cultivars with different NUE is still obscure. For this purpose, two rice cultivars differing in NUE were chosen for this study, one with high-NUE (Dexiang 4103) and the other with low-NUE (Yixiang 3724). Fertilizers were applied at three levels, including low (75 kg N·hm-2, 37.5 kg P2O5·hm-2, 75 kg K2O·hm-2), medium (150 kg N·hm-2, 75 kg P2O5·hm-2, 150 kg K2O·hm-2), high rate (225 kg N·hm-2, 112.5 kg P2O5·hm-2, 225 kg K2O·hm-2). A no-N treatment was included for each level as the control. The results showed that there were obvious interacting effects of cultivars and fertilizer levels on grain yield, as well as the absorption and translocation of P and K. Rice cultivars exhibited markedly stronger effects on total spikelets and the translocation of P and K in leaves, compared to fertilizer levels. The opposite trend was observed for grain yield, P and K accumulation at the main growth stages, and P and K translocation in stem and leaf sheaths. Compared with other treatments, the combined application of NPK fertilizers at medium level promoted nutrient accumulation, increased the nutrient harvest index, facilitated nutrient translocation in vegetative organs, and ultimately improved grain yield in both cultivars. The equilibrium relationship between N, P and K accumulation and grain yield indicated that the grain yield associated with high-NUE cultivar could reach more than 10,000 kg hm-2, with N, P, and K requirements of 180.8-213.3, 47.3-54.7, and 223.5-259.1 kg hm-2, respectively. Additionally, the correlation analysis revealed that accumulation and translocation of P, K during different growth stages was significantly (P < 0.05) related to grain yield and nutrient accumulation in different NUE cultivars. This study suggested that varieties with high-NUE also has high P and K use efficiencies, indicating that the conventional screening of varieties with high P or K use efficiencies can be included in the selection of high-NUE varieties. The increase of P and K accumulation and translocation during the period from heading to maturity was helpful to maintain a high-yield and NUE in rice production.
Morphological Variation in Selected Accessions of Bambara Groundnut (Vigna subterranea L. Verdc) in South Africa
Authors: Unigwe Amara Evangeline , Gerrano Abe Shegro , Adebola Patrick , Pillay Michael
Published: October 2016

Bambara groundnut (Vigna subterranea L. Verdc) is an underutilized crop in the African continent. It is a drought tolerant crop and fixes atmospheric nitrogen. Bambara groundnut is primarily grown for the protein content of its seeds and is mainly produced by small scale farmers at subsistence level. The objective of the study was to assess the morphological variation of landraces of bambara groundnut in South Africa. Thirty accessions of bambara groundnut were evaluated for their variability in agronomic and morphological traits. The field experiment was conducted at ARC-VOPI in Roodeplaat research farm during the 2014/2015 summer cropping season. The field trial was arranged as a complete randomized block design with three replications. Eighteen quantitative traits were recorded to estimate the level of genetic variability among accessions. The analysis of variance revealed significant differences among the phenotypic traits evaluated. The UPGMA cluster analysis based on the quantitative traits produced four distinct groups of genotypes and a singleton. Genotypes SB11-1A, SB19-1A, SB12-3B and Bambara-12 were found to possess good vegetative characters and are recommended for use as suitable parents when breeding cultivars for fodder production. Desirable yield and yield-related traits were identified in B7-1, SB4-4C, SB19-1A, Bambara-12 and SB16-5A and are recommended as suitable parental lines for bambara groundnut grain production improvement. The phenotypic characters therefore provide a useful measure of genetic variability among bambara genotypes and will enable the identification of potential parental materials for future breeding programs in South Africa.
Systemic Delivery of Bone Marrow Mesenchymal Stem Cells for In Situ Intervertebral Disc Regeneration
Authors: Cunha Carla , Almeida Catarina R. , Almeida Maria Inês , Silva Andreia M. , Molinos Maria , Lamas Sofia , Pereira Catarina L. , Teixeira Graciosa Q. , Monteiro António T. , Santos Susana G. , Gonçalves Raquel M. , Barbosa Mário A.
Published: October 2016

Cell therapies for intervertebral disc (IVD) regeneration presently rely on transplantation of IVD cells or stem cells directly to the lesion site. Still, the harsh IVD environment, with low irrigation and high mechanical stress, challenges cell administration and survival. In this study, we addressed systemic transplantation of allogeneic bone marrow mesenchymal stem cells (MSCs) intravenously into a rat IVD lesion model, exploring tissue regeneration via cell signaling to the lesion site. MSC transplantation was performed 24 hours after injury, in parallel with dermal fibroblasts as a control; 2 weeks after transplantation, animals were killed. Disc height index and histological grading score indicated less degeneration for the MSC-transplanted group, with no significant changes in extracellular matrix composition. Remarkably, MSC transplantation resulted in local downregulation of the hypoxia responsive GLUT-1 and in significantly less herniation, with higher amounts of Pax5+ B lymphocytes and no alterations in CD68+ macrophages within the hernia. The systemic immune response was analyzed in the blood, draining lymph nodes, and spleen by flow cytometry and in the plasma by cytokine array. Results suggest an immunoregulatory effect in the MSC-transplanted animals compared with control groups, with an increase in MHC class II+ and CD4+ cells, and also upregulation of the cytokines IL-2, IL-4, IL-6, and IL-10, and downregulation of the cytokines IL-13 and TNF-α. Overall, our results indicate a beneficial effect of systemically transplanted MSCs on in situ IVD regeneration and highlight the complex interplay between stromal cells and cells of the immune system in achieving successful tissue regeneration.
Generalized division polynomials
Authors: Satoh Takakazu
Published: October 2016

Let $E$ be an elliptic curve with complex multiplication by the ring $O_{F}$ of integers of an imaginary quadratic field $F$. We give an explicit condition on $\alpha\in O_{F}$ so that there exists a rational function $\psi_{\alpha}$ satisfying $\div\psi_{\alpha}=\sum_{P\in\mathrm{Ker}[\alpha]}[P] - N_{F /Q}(\alpha)[{\mathcal{O}}]$ where $[\alpha ]$ is the multiplication by $\alpha$ map. We give an algorithm to compute $\psi_{\alpha}$ based on recurrence formulas among these functions. We prove that the time complexity of this algorithm is $O(N_{F/Q}(\alpha )^{2+\varepsilon})$ bit operations under an FFT based multiplication algorithm as $N_{F /Q}(\alpha )$ tends to infinity for the fixed $E$.
Fuchsian groups generated by half-turns and geometrical characterization of hyperelliptic and symmetric Riemann surfaces
Authors: Etayo J. J. , Martínez E.
Published: October 2016

We construct a special type of fundamental regions for any Fuchsian group $F$ generated by an even number of half-turns, and for certain non-Euclidean crystallographic groups (NEC groups in short). By comparing these regions we give geometrical conditions in order to $F$ be the canonical Fuchsian subgroup of one of those NEC groups. Precisely speaking, we deal with NEC groups of algebraic genus $0$ having all periods in the signature equal to $2$. By means of these conditions we give a characterization of hyperelliptic and symmetric Riemann surfaces.
The Drosophila formin Fhos is a primary mediator of sarcomeric thin-filament array assembly
Authors: Shwartz Arkadi , Dhanyasi Nagaraju , Schejter Eyal D , Shilo Ben-Zion
Published: October 2016

Actin-based thin filament arrays constitute a fundamental core component of muscle sarcomeres. We have used formation of the Drosophila indirect flight musculature for studying the assembly and maturation of thin-filament arrays in a skeletal muscle model system. Employing GFP-tagged actin monomer incorporation, we identify several distinct phases in the dynamic construction of thin-filament arrays. This sequence includes assembly of nascent arrays after an initial period of intensive microfilament synthesis, followed by array elongation, primarily from filament pointed-ends, radial growth of the arrays via recruitment of peripheral filaments and continuous barbed-end turnover. Using genetic approaches we have identified Fhos, the single Drosophila homolog of the FHOD sub-family of formins, as a primary and versatile mediator of IFM thin-filament organization. Localization of Fhos to the barbed-ends of the arrays, achieved via a novel N-terminal domain, appears to be a critical aspect of its sarcomeric roles.
Primate amygdala neurons evaluate the progress of self-defined economic choice sequences
Authors: Grabenhorst Fabian , Hernadi Istvan , Schultz Wolfram
Published: October 2016

The amygdala is a prime valuation structure yet its functions in advanced behaviors are poorly understood. We tested whether individual amygdala neurons encode a critical requirement for goal-directed behavior: the evaluation of progress during sequential choices. As monkeys progressed through choice sequences toward rewards, amygdala neurons showed phasic, gradually increasing responses over successive choice steps. These responses occurred in the absence of external progress cues or motor preplanning. They were often specific to self-defined sequences, typically disappearing during instructed control sequences with similar reward expectation. Their build-up rate reflected prospectively the forthcoming choice sequence, suggesting adaptation to an internal plan. Population decoding demonstrated a high-accuracy progress code. These findings indicate that amygdala neurons evaluate the progress of planned, self-defined behavioral sequences. Such progress signals seem essential for aligning stepwise choices with internal plans. Their presence in amygdala neurons may inform understanding of human conditions with amygdala dysfunction and deregulated reward pursuit.
A model providing long‐term data sets of energetic electron precipitation during geomagnetic storms
Authors: van de Kamp M. , Seppälä A. , Clilverd M. A. , Rodger C. J. , Verronen P. T. , Whittaker I. C.
Published: October 2016

The influence of solar variability on the polar atmosphere and climate due to energetic electron precipitation (EEP) has remained an open question largely due to lack of a long‐term EEP forcing data set that could be used in chemistry‐climate models. Motivated by this, we have developed a model for 30–1000 keV radiation belt driven EEP. The model is based on precipitation data from low Earth orbiting POES satellites in the period 2002–2012 and empirically described plasmasphere structure, which are both scaled to a geomagnetic index. This geomagnetic index is the only input of the model and can be either Dst or Ap. Because of this, the model can be used to calculate the energy‐flux spectrum of precipitating electrons from 1957 (Dst) or 1932 (Ap) onward, with a time resolution of 1 day. Results from the model compare well with EEP observations over the period of 2002–2012. Using the model avoids the challenges found in measured data sets concerning proton contamination. As demonstrated, the model results can be used to produce the first ever >80 year long atmospheric ionization rate data set for radiation belt EEP. The impact of precipitation in this energy range is mainly seen at altitudes 70–110 km. The ionization rate data set, which is available for the scientific community, will enable simulations of EEP impacts on the atmosphere and climate with realistic EEP variability. Due to limitations in this first version of the model, the results most likely represent an underestimation of the total EEP effect.
Structure of magma reservoirs beneath Merapi and surrounding volcanic centers of Central Java modeled from ambient noise tomography
Authors: Koulakov Ivan , Maksotova Gulzhamal , Jaxybulatov Kayrly , Kasatkina Ekaterina , Shapiro Nikolai M. , Luehr Birger‐G. , El Khrepy Sami , Al‐Arifi Nassir
Published: October 2016

We present a three‐dimensional model of the distribution of S‐wave velocity in the upper crust to a depth of 20 km beneath Central Java based on the analysis of seismic ambient noise data recorded by more than 100 seismic stations in 2004 associated with the MERAMEX project. To invert the Rayleigh wave dispersion curves to construct 2‐D group‐velocity maps and 3‐D distributions of S‐wave velocity, we have used a new tomographic algorithm based on iterative linearized inversion. We have performed a series of synthetic tests that demonstrate significantly higher resolution in the upper crust with this model compared to the local earthquake travel‐time tomography (LET) model previously applied for the same station network. Beneath the southern flank of Merapi, we identify a large low‐velocity anomaly that can be split into two layers. The upper layer reflects the ∼1 km thick sedimentary cover of volcanoclastic deposits. The deeper anomaly at depths of ∼4–8 km may represent a magma reservoir with partially molten rock that feeds several volcanoes in Central Java. Beneath the Merapi summit, we observe another low‐velocity anomaly as deep as 8 km that may be associated with the active magma reservoir that feeds the eruptive activity of Merapi. In the southern portion of the study area, in the lower crust, we identify a low‐velocity anomaly that may represent the top of the pathways of volatiles and melts ascending from the slab that was previously inferred from the LET model results. We observe that this anomaly is clearly separate from the felsic magma reservoirs in the upper crust.
Spawning superplumes from the midmantle: The impact of spin transitions in the mantle
Authors: Shahnas M. H. , Pysklywec R. N. , Yuen D. A.
Published: October 2016

The formation of large‐scale upwellings with lateral extents of several hundreds of kilometers, reaching up to ∼10,000 km or more, still remains a hotly debated topic. Some seismic imaging studies based on high‐resolution data suggest that the main superplumes underneath Africa and South‐central Pacific are clusters, composed of several individual plumes rather than being a single large mantle upwelling. The iron spin transition in the lower mantle minerals may present a new idea on the origin and the formation of such superplumes, notably sourcing such features in the midmantle. Stagnation of both cold sinking slabs and hot rising plumes can be caused by density and viscosity variation due to the spin transition in iron in ferropericlase (Fp) and a possible spin‐dependent bulk modulus hardening in bridgmanite silicate perovskite (Pv). This process produces intermittent downward spin transition‐induced midmantle avalanches (SIMMA) of the cold sinking flow as well as upward spin transition‐induced midmantle superplume avalanches (SIMMSA) of the rising hot plumes, triggered at the spin transition‐induced thermal boundary layer at around 1600 km depth. Our high‐resolution axi‐symmetric models reveal that the hot upwellings, trapped below ∼1600 km depth, can suddenly penetrate into the upper levels in the mantle and spread laterally for hundreds of kilometres. Owing to the upward penetration of the midmantle‐rooted superplumes, as broad as ∼1500 km across, a large amount of heat can be delivered to the upper mantle and base of the lithosphere with implications for large volcanic episodes.
The change in contact angle at unsaturated CO2‐water conditions: Implication on geological carbon dioxide sequestration
Authors: Jafari Mohammad , Jung Jongwon
Published: October 2016

The performance of a geologic carbon storage site strongly depends on the capillary pressure of sealing rock and formations. While wettability of minerals is a key factor in capillary pressure, published contact angles are inconsistent. This study explores the discrepancy of published contact angles in order to reduce the uncertainty of measured laboratory contact angles, and understand the variation of contact angles at unsaturated CO2‐water conditions. A ratio of droplet dimension and triple line (or contact line) are used to explain the observed wide range of contact angles and the variation of contact angle at unsaturated conditions. Results show that the shape factor has a good agreement with contact angle change during CO2 dissolution in water. Silica substrate has clear two pinned and slip stages of triple line during CO2 droplet dissolution, which cause contact angle on silica substrate to increase from 34.5° to 42.1°. However, mica substrate has the repeated pinned and slip stages due to the heterogeneity of mica surface, which cause contact angle to increase dramatically from 25.4° to 68.1°. Thus, both the impact of the unsaturated CO2‐water conditions on the wide range of contact angle and the heterogeneity of mineral surface should be considered when one estimates capillary pressure based on contact angle in geological CO2 sequestration.
Tectonic structure of the Mid‐Atlantic Ridge near 16°30′N
Authors: Parnell‐Turner Ross , Schouten Hans , Smith Deborah K.
Published: October 2016

The 16°30'N area of the Mid‐Atlantic Ridge represents an area of present‐day detachment faulting. Here we present shipboard bathymetric, magnetic and gravity data acquired up to 65 km from the ridge axis that reveal a varied tectonic history of this region. Magnetic data are used to calculate spreading rates and examine spreading rate variability along and across the axis. Bathymetric and gravity data are used to infer the crustal structure. A central magnetic anomaly 40% narrower than expected is observed along much of the study area. Misalignment between modern‐day spreading center and magnetic anomalies indicates tectonic reorganization of the axis within the past 780 ka. Observed magnetic anomalies show a pattern of anomalous skewness consistent with rotation of magnetic vectors probably associated with detachment faulting. Relatively thin crust north of a small (∼7 km) nontransform offset coincides with a weakly magmatic spreading axis. In contrast, to the south a robust axial volcanic ridge is underlain by thicker crust. Variations in crustal structure perpendicular to the axis occur over tens of kilometers, indicating processes which occur over timescales of 1–2 Ma.
Reconciling mantle wedge thermal structure with arc lava thermobarometric determinations in oceanic subduction zones
Authors: Perrin Alexander , Goes Saskia , Prytulak Julie , Davies D. Rhodri , Wilson Cian , Kramer Stephan
Published: October 2016

Subduction zone mantle wedge temperatures impact plate interaction, melt generation, and chemical recycling. However, it has been challenging to reconcile geophysical and geochemical constraints on wedge thermal structure. Here we chemically determine the equilibration pressures and temperatures of primitive arc lavas from worldwide intraoceanic subduction zones and compare them to kinematically driven thermal wedge models. We find that equilibration pressures are typically located in the lithosphere, starting just below the Moho, and spanning a wide depth range of ∼25 km. Equilibration temperatures are high for these depths, averaging ∼1300°C. We test for correlations with subduction parameters and find that equilibration pressures correlate with upper plate age, indicating overriding lithosphere thickness plays a role in magma equilibration. We suggest that most, if not all, thermobarometric pressure and temperature conditions reflect magmatic reequilibration at a mechanical boundary, rather than reflecting the conditions of major melt generation. The magma reequilibration conditions are difficult to reconcile, to a first order, with any of the conditions predicted by our dynamic models, with the exception of subduction zones with very young, thin upper plates. For most zones, a mechanism for substantially thinning the overriding plate is required. Most likely thinning is localized below the arc, as kinematic thinning above the wedge corner would lead to a hot fore arc, incompatible with fore‐arc surface heat flow and seismic properties. Localized subarc thermal erosion is consistent with seismic imaging and exhumed arc structures. Furthermore, such thermal erosion can serve as a weakness zone and affect subsequent plate evolution.
Reverse flow events and small‐scale effects in the cusp ionosphere
Authors: Spicher A. , Ilyasov A. A. , Miloch W. J. , Chernyshov A. A. , Clausen L. B. N. , Moen J. I. , Abe T. , Saito Y.
Published: October 2016

We report in situ measurements of plasma irregularities associated with a reverse flow event (RFE) in the cuspFregion ionosphere. The Investigation of Cusp Irregularities 3 (ICI‐3) sounding rocket, while flying through a RFE, encountered several regions with density irregularities down to meter scales. We address in detail the region with the most intense small‐scale fluctuations in both the density and in the AC electric field, which were observed on the equatorward edge of a flow shear, and coincided with a double‐humped jet of fast flow. Due to its long‐wavelength and low‐frequency character, the Kelvin‐Helmholtz instability (KHI) alone cannot be the source of the observed irregularities. Using ICI‐3 data as inputs, we perform a numerical stability analysis of the inhomogeneous energy‐density‐driven instability (IEDDI) and demonstrate that it can excite electrostatic ion cyclotron waves in a wide range of wave numbers and frequencies for the electric field configuration observed in that region, which can give rise to the observed small‐scale turbulence. The IEDDI can seed as a secondary process on steepened vortices created by a primary KHI. Such an interplay between macroprocesses and microprocesses could be an important mechanism for ion heating in relation to RFEs.
Small‐scale thermal upwellings under the northern East African Rift from S travel time tomography
Authors: Civiero Chiara , Goes Saskia , Hammond James O. S. , Fishwick Stewart , Ahmed Abdulhakim , Ayele Atalay , Doubre Cecile , Goitom Berhe , Keir Derek , Kendall J. Michael , Leroy Sylvie , Ogubazghi Ghebrebrhan , Rümpker Georg , Stuart Graham W.
Published: October 2016

There is a long‐standing debate over how many and what types of plumes underlie the East African Rift and whether they do or do not drive its extension and consequent magmatism and seismicity. Here we present a new tomographic study of relative teleseismic S and SKS residuals that expands the resolution from previous regional studies below the northern East African Rift to image structure from the surface to the base of the transition zone. The images reveal two low‐velocity clusters, below Afar and west of the Main Ethiopian Rift, that extend throughout the upper mantle and comprise several smaller‐scale (about 100 km diameter), low‐velocity features. These structures support those of our recent P tomographic study below the region. The relative magnitude of S to P residuals is around 3.5, which is consistent with a predominantly thermal nature of the anomalies. The S and P velocity anomalies in the low‐velocity clusters can be explained by similar excess temperatures in the range of 100–200°C, consistent with temperatures inferred from other seismic, geochemical, and petrological studies. Somewhat stronger VS anomalies below Afar than west of the Main Ethiopian Rift may include an expression of volatiles and/or melt in this region. These results, together with a comparison with previous larger‐scale tomographic models, indicate that these structures are likely small‐scale upwellings with mild excess temperatures, rising from a regional thermal boundary layer at the base of the upper mantle.
The transport of Icelandic volcanic ash: Insights from northern European cryptotephra records
Authors: Watson E. J. , Swindles G. T. , Stevenson J. A. , Savov I. , Lawson I. T.
Published: October 2016

Fine ash produced during volcanic eruptions can be dispersed over a vast area, where it poses a threat to aviation, human health, and infrastructure. We analyze the particle size distributions, geochemistry, and glass shard morphology of 19 distal (>1000 km from source) volcanic ash deposits distributed across northern Europe, many geochemically linked to a specific volcanic eruption. The largest glass shards in the cryptotephra deposits were 250 µm (longest axis basis). For the first time, we examine the replicability and reliability of glass shard size measurements from peatland and lake archives. We identify no consistent trend in the vertical sorting of glass shards by size within lake and peat sediments. Measuring the sizes of 100 shards from the vertical sample of peak shard concentration is generally sufficient to ascertain the median shard size for a cryptotephra deposit. Lakes and peatlands in close proximity contain cryptotephras with significantly different median shard size in four out of five instances. The trend toward a greater amount of larger shards in lakes may have implications for the selection of distal sites to constrain the maximum glass shard size for modeling studies. Although the 95th percentile values for shard size generally indicate a loss of larger shards from deposits at sites farther from the volcano, due to the dynamic nature of the controls on tephra transport even during the course of one eruption there is no simple relationship between median shard size and transport distance.
Long‐term decrease in phosphate concentrations in the surface layer of the southern Japan Sea
Authors: Kodama Taketoshi , Igeta Yosuke , Kuga Mizuki , Abe Shoko
Published: October 2016

To identify possible causes for the long‐term trends in nutrient concentrations in the southern Japan Sea (JS), we studied nutrient concentrations that were obtained by the Japan Meteorological Agency. Our evaluation shows that phosphate concentrations declined in the surface layers in summer (0–20 and 21–50 m depth) and winter (0–20, 21–50, and 51–100 m depth) over the last 40 years, while no significant linear trend was observed for nitrate concentrations. The declining trend in the phosphate concentration was quantified as 1.8–3.3 nM yr−1. The increase in atmospheric nutrient deposition to the JS could not explain the decline in phosphate concentration. In addition, the mixed‐layer depth during winter did not demonstrate any significant trend, and an increase in phosphate concentrations was not observed in any layers; therefore, the decrease in nutrient supply from deep JS water was not considered a major possible cause for the decline in the phosphate concentration. In contrast, the phosphate concentration in the surface of the southern JS during winter showed a significant positive correlation with the concentration in the 21–50 m depth layer of the saline East China Sea (ECS) water in the preceding summer, and the surface water of the southern JS was almost entirely replaced by water originating from the ECS during May–October. Therefore, it is concluded that the declining trend in the phosphate concentrations in the southern JS is caused by horizontal advection of ECS water.