bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of bicarbonate use influence the photosynthetic carbon dioxide sensitivity of tropical seagrasses
Authors: Campbell Justin E. , Fourqurean James W.
Published: August 2016

The photosynthetic bicarbonate () use properties of three widely distributed tropical seagrasses were compared using a series of laboratory experiments. Photosynthetic rates of Thalassia testudinum, Halodule wrightii, and Syringodium filiforme were monitored in an enclosed chamber while being subjected to shifts in pH and dissolved inorganic carbon. Specific mechanisms of seagrass use were compared by examining the photosynthetic effects of the carbonic anhydrase inhibitor acetazolamide (AZ). All seagrasses increased photosynthetic rates with reduced pH, suggesting a large effect of dissolved aqueous carbon dioxide (CO2(aq)). However, there was considerable interspecific variation in pH response. T. testudinum was highly sensitive, increasing photosynthetic rates by 100% as the pH was reduced from 8.2 to 7.4, whereas rates in H. wrightii and S. filiforme increased by only 20% over a similar range, and displayed prominent photosynthetic plateaus, indicating an increased capacity for use. Additional incubations that manipulated [] under constant [CO2(aq)] support these findings, as only H. wrightii and S. filiforme increased photosynthetic rates with increasing []. T. testudinum responded to AZ addition, indicating that carbonic anhydrase enzymes facilitate limited use. H. wrightii and S. filiforme showed no response to AZ, suggesting alternate, more efficient mechanisms of use. Estimated kinetic parameters, Ks(CO2) and Vmax, revealed interspecific variation and further support these conclusions. Variation in photosynthetic pH responses and AZ sensitivity indicate distinctions in the carbon use properties of seagrasses exposed to similar environmental conditions. These results suggest that not all seagrasses will similarly respond to future increases in CO2(aq) availability. Attention towards potential shifts in competitive interactions within multispecific seagrass beds is warranted.
Diel and lunar cycles of vertical migration extending to below 1000 m in the ocean and the vertical connectivity of depth‐tiered populations
Authors: Ochoa José , Maske H. , Sheinbaumc J. , Candela J.
Published: August 2016

We measured diel migration with 11 acoustic Doppler current meter profilers and consistently found diel and lunar cycles of vertical migration from 250 m down to the bathypelagic (> 1000 m). These measurements come from year‐long deployments in eight locations within the Gulf of Mexico. Diel vertical migration could be characterized, in depth and time, by a pulse of maximum vertical migration activity (PMV), which has a nearly fix phase relation to sunrise and sunset modulated by the lunar cycle. The vertical velocity of migrating biota is in the same direction as the PMV propagation, but it is significantly slower. This difference in velocity implies that the PMV cannot represent the migration pattern of one single population. The lunar cycle is evident down to 1000 m, where the upward migration delays in phase with the full moon. The extension of the diel and lunar cycles over 1000 m depth together with the difference in vertical migration velocity indicate that the surface irradiance signal is transmitted to bathypelagic depth by synchronized depth‐tiered populations. A model in which particulate organics are recycled at different depths, similar to a bucket brigade, is consistent with these observations. This daily vertical connectivity is expected to affect the vertical transport of carbon down to the bathypelagic.
Pelagic metabolism in the waters of the Great Barrier Reef
Authors: McKinnon A. D. , Logan M. , Castine S. A. , Duggan S.
Published: August 2016

Pelagic metabolism (community respiration [CR] and net community production [NCP]) were measured in oxygen flux experiments at 14 locations in waters of the Great Barrier Reef (GBR) lagoon between 16°S and 23°S during the dry seasons of 2008 and 2009 and the wet seasons of 2009 and 2010. These were compared to similar experiments conducted in the wet season of 2005 in the far northern GBR (14°S). Seasonality (wet and dry season) was the greatest determinant of respiration rate, with median CR values of 1.85 mmol O2 m−3 d−1 in the dry season and 2.87 mmol O2 m−3 d−1 in the wet season. NCP normally ranged up to 9.16 mmol O2 m−3 d−1, depending on depth and phytoplankton biomass, though an extreme value of 14.96 mmol O2 m−3 d−1 occurred during flood conditions. Cross‐shelf effects had a strong influence on physicochemical variables but weaker effects on both CR and NCP, though both were higher inshore. All but two stations were net autotrophic, with a median ratio of gross primary production : CR of 1.5. Area‐specific CR was 72 ± 23 standard deviation (SD) mmol O2 m−2 d−1 in the dry season and 94 ± 27 SD mmol O2 m−2 d−1 in the wet season. Area‐specific NCP was lower in the dry season (41 ± 33 SD mmol O2 m−2 d−1) than in the wet season (55 ± 54 SD mmol O2 m−2 d−1). Peaks in area‐specific NCP were associated with floods, intrusions of nutrient‐rich sub‐thermocline Coral Sea water, and localized phytoplankton blooms but otherwise showed few seasonal or spatial trends. Overall, CR in GBR lagoon waters was comparable to rates in oligotrophic oceanic waters, but NCP was more typical of shelf systems.
Quantifying the production of dissolved organic nitrogen in headwater streams using 15N tracer additions
Authors: Johnson Laura T. , Tank Jennifer L. , Hall, Jr. Robert O. , Mulholland Patrick J. , Hamilton Stephen K. , Valett H. Maurice , Webster Jackson R. , Bernot Melody J. , McDowell William H. , Peterson Bruce J. , Thomas Suzanne M.
Published: August 2016

Most nitrogen (N) assimilation in lake and marine ecosystems is often subsequently released via autochthonous dissolved organic nitrogen (DON) production, but autochthonous DON production has yet to be quantified in flowing waters. We measured in‐stream DON production following 24 h 15N‐nitrate () tracer additions in 36 headwater streams, a subset of sites from the second Lotic Intersite Nitrogen eXperiment. Streams were located in five North American ecoregions and drained basins dominated by native vegetation, agriculture, or urban land use. Using a two‐compartment model, we could quantify DON production in 15 streams as a function of DO15N derived from 15N tracer in biomass compartments. The streams with detectable DON production had higher % modified land use (agriculture + urban) in their basins than did streams with undetectable DON production. Median DON production represented 8% of total uptake when we used N biomass estimates based on N assimilated over 1 d (measured directly from the 15N additions). Median DON production was 17% of total uptake when we used N assimilated over 42 d (extrapolated from previous 15N tracer studies). Variation in DON production was positively correlated with ecosystem respiration, indicating that stream heterotrophy may influence DON production. In‐stream DON production was similar in magnitude to stream denitrification and nitrification, indicating that the production of autochthonous DON can represent a substantial transformation of stream N. Our results confirm that headwater streams can quickly convert inorganic N into organic forms, although the ultimate fate of DON remains unclear.
Fine spatial structure of genetically distinct picocyanobacterial populations across environmental gradients in the Costa Rica Dome
Authors: Gutiérrez-Rodríguez Andrés , Slack Gillian , Daniels Emy F. , Selph Karen E. , Palenik Brian , Landry Michael R.
Published: August 2016

We investigated the spatial variability of picocyanobacterial community structure across the Costa Rica Dome (CRD), an offshore upwelling system characterized by high seasonal abundance of Synechococcus spp. We constructed clone libraries of the rpoC1 gene to survey picocyanobacterial diversity and developed specific real‐time quantitative polymerase chain reaction assays to assess the distribution of genetically distinct Synechococcus (SYN) and Prochlorococcus (PRO) populations across vertical and horizontal physicochemical gradients. Flow cytometry data showed that cell abundances for both SYN and PRO were highest near the dome center. Phylogenetic analysis of rpoC1 sequences revealed a remarkably high and distinctive picocyanobacterial diversity (FLU1‐3, CRD1, Clade II, XV, XVI) that included “novel” SYN and PRO genotypes. Furthermore, genetically different populations exhibited vertical and horizontal spatial partitioning. Abundances of distinct SYN genotypes peaked at subsequent depth horizons, leading to a fine vertical structure with at least three populations stacked within the upper 30–40 m at the dome. Clade II and FLU1A peaked in surface waters, while maximum concentrations of CRD1, FLU1B, and Clade XVI occurred in the upper and lower thermocline, respectively. Horizontally, Clade II abundance in surface waters remained high across the entire region, while SYN genotypes CRD1 and FLU1A increased with shoaling of the thermo‐ and nutricline toward the center of the dome to become the dominant genotypes of the SYN assemblage in the dome. Below the mixed layer, Clade XVI and PRO genotype FLU2, virtually absent outside the dome, became abundant components of the picocyanobacterial assemblage. Despite their phylogenetic relatedness, FLU1A and FLU1B subclades followed different distributional patterns, suggesting ecological significance of the microdiversity within the clade. The unprecedented fine vertical structure demonstrated for SYN genotypes is driven by sharp physicochemical gradients (e.g., density, nutrient, oxygen, and trace metals) created by the dome and the presence of a shallow oxycline that enhances habitat diversification.
Shortwave radiative forcing and feedback to the surface by sulphate geoengineering: Analysis of the Geoengineering Model Intercomparison Project G4 scenario
Authors: Kashimura Hiroki , Abe Manabu , Watanabe Shingo , Sekiya Takashi , Ji Duoying , Moore John C. , Cole Jason N. S. , Kravitz Ben
Published: August 2016

Abstract. This study evaluates the forcing and feedback of net shortwave radiation at the surface in the G4 experiment of the Geoengineering Model Intercomparison Project by analysing outputs from six participating models. G4 involves injection of 5 Tg yr−1 of SO2, a sulphate aerosol precursor, into the lower stratosphere from year 2020 to 2070 against a background scenario of RCP4.5. A single layer atmospheric model for shortwave radiative transfer is used to estimate the direct forcing of solar radiation management (SRM) and feedback effects from changes in the water vapour amount, cloud amount, and surface albedo (compared with RCP4.5). The analysis shows that the globally and temporally averaged SRM forcing ranges from −3.6 to −1.6 W m−2, depending on the model. The feedback effects due to changes in the water vapour and cloud amounts on net shortwave radiation have heating effects ranging from approximately 0.4 to 1.5 W m−2 and weaken the effect of SRM by around 50 %. The surface albedo changes have a cooling effect, which is locally strong (~ 4 W m−2) in snow and sea ice melting regions, but minor for the global average. The analyses show that the results of the G4 experiment, which simulates sulphate geoengineering, include large inter-model variability both in the direct SRM forcing and the feedback from changes in the cloud amount, and imply a high uncertainty in modelled processes of sulphate aerosols and clouds.
Cloud Detection in All-Sky Images via Multi-scale
Neighborhood Features and Multiple Supervised Learning
Techniques
Authors: Cheng Hsu-Yung , Lin Chih-Lung
Published: August 2016

Abstract. Cloud detection is important for providing necessary information such as cloud cover in many applications. The classic method for cloud detection is based on thresholding of the red blue ratio of an image pixel. However, it is difficult to select a suitable threshold for all cloud conditions. Also, the desired thresholds for different all-sky cameras are different. In this paper, we propose to perform cloud detection using supervised learning techniques. The features are extracted from local image patches with different sizes to include local structure and multi-resolution information. The cloud models are learned through the training process. We consider classifiers including random forest, support vector machine and Bayesian classifier. To take advantage of the clues provided by multiple classifiers and various levels of patch sizes, we employ a voting scheme to combine the results to further increase the detection accuracy. In the experiments, we have shown that the proposed method can distinguish cloud and non-cloud pixels more accurately compared with existing works.
A multi-wavelength classification method for polar stratospheric cloud types
using infrared limb spectra
Authors: Spang Reinhold , Hoffmann Lars , Höpfner Michael , Griessbach Sabine , Müller Rolf , Pitts Michael C. , Orr Andrew M. W. , Riese Martin
Published: August 2016

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on board the ESA Envisat satellite operated from July 2002 until April 2012. The infrared limb emission measurements represent a unique dataset of daytime and night-time observations of polar stratospheric clouds (PSCs) up to both poles. Cloud detection sensitivity is comparable to space-borne lidars, and it is possible to classify different cloud types from the spectral measurements in different atmospheric windows regions. Here we present a new infrared PSC classification scheme based on the combination of a well-established two-colour ratio method and multiple 2-D brightness temperature difference probability density functions. The method is a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption. The method has been tested in conjunction with a database of radiative transfer model calculations of realistic PSC particle size distributions, geometries, and composition. The Bayesian classifier distinguishes between solid particles of ice and nitric acid trihydrate (NAT), as well as liquid droplets of super-cooled ternary solution (STS). The classification results are compared to coincident measurements from the space-borne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument over the temporal overlap of both satellite missions (June 2006–March 2012). Both datasets show a good agreement for the specific PSC classes, although the viewing geometries and the vertical and horizontal resolution are quite different. Discrepancies are observed between the CALIOP and the MIPAS ice class. The Bayesian classifier for MIPAS identifies substantially more ice clouds in the Southern Hemisphere polar vortex than CALIOP. This disagreement is attributed in part to the difference in the sensitivity on mixed-type clouds. Ice seems to dominate the spectral behaviour in the limb infrared spectra and may cause an overestimation in ice occurrence compared to the real fraction of ice within the PSC area in the polar vortex. The entire MIPAS measurement period was processed with the new classification approach. Examples like the detection of the Antarctic NAT belt during early winter, and its possible link to mountain wave events over the Antarctic Peninsula, which are observed by the Atmospheric Infrared Sounder (AIRS) instrument, highlight the importance of a climatology of 9 Southern Hemisphere and 10 Northern Hemisphere winters in total. The new dataset is valuable both for detailed process studies, and for comparisons with and improvements of the PSC parameterizations used in chemistry transport and climate models.
Consistent EO Land Surface Products including Uncertainty Estimates
Authors: Kaminski Thomas , Pinty Bernard , Voßbeck Michael , Lopatka Maciej , Gobron Nadine , Robustelli Monica
Published: August 2016

Abstract. Earth Observation (EO) land products have been demonstrated to provide a constraint on the terrestrial carbon cycle that is complementary to the record of atmospheric carbon dioxide. We present the Joint Research Centre Two-stream Inversion Package (JRC-TIP) for retrieval of variables characterising the state of the vegetation-soil system. The system provides a set of land surface variables that satisfy all requirements for assimilation into the land component of climate and numerical weather prediction models. Being based on a one dimensional representation of the radiative transfer within the canopy-soil system such as those used in the land surface components of advanced global models, the JRC-TIP products are not only physically consistent internally, but also achieve a high degree of consistency with these global models. Furthermore, the products are provided with full uncertainty information. We describe how these uncertainties are derived in a fully traceable manner without any hidden assumptions from the input observations, which are typically broadband white sky albedo products. Our discussion of the product uncertainty ranges, including the uncertainty reduction, highlights the central role of the leaf area index which describes the density of the canopy. We explain the generation of products aggregated to coarser spatial resolution than that of the native albedo input and describe various approaches to validation of JRC-TIP products, including the comparison against in-situ observations. We present a JRC-TIP processing system that satisfies all operational requirements and explain how it delivers stable climate data records. As many aspects of JRC-TIP are generic the package can serve as an example of a state-of-the-art system for retrieval of EO products, and this contribution can help the user to understand advantages and limitations of such products.
Reinitialised versus continuous regional climate simulations using ALARO-0 coupled to the land surface model SURFEX
Authors: Berckmans Julie , Giot Olivier , De Troch Rozemien , Hamdi Rafiq , Ceulemans Reinhart , Termonia Piet
Published: August 2016

Abstract. The potential of the implementation of the land surface model SURFEX in the atmospheric ALARO-0 model configuration of the ALADIN system is tested in a continuous regional climate simulation. This contribution is evaluated with respect to the regional climate simulated by the original setup of ALARO-0 with ISBA. Next, an assessment has been performed to evaluate the continuous setup with an upper air daily reinitialised setup, where the surface is kept in a freely continuous mode. The results show that the introduction of SURFEX improves or has a neutral impact on the 2 m temperature and the daily total precipitation. More importantly, the use of an upper air daily reinitialised atmosphere outperforms the setup with a continuous atmosphere, for the 2 m temperature in winter and summer, and for the summer daily total precipitation. The differences between the two downscaling setups in the 2 m temperature and precipitation interact with the soil moisture. This coupling is strong for the continental areas, which motivates the use of a coupled land-atmosphere model to optimise the representation of the climate.
A review of marine geomorphometry, the quantitative study of the seafloor
Authors: Lecours Vincent , Dolan Margaret F. J. , Micallef Aaron , Lucieer Vanessa L.
Published: August 2016

Abstract. Geomorphometry, the science of quantitative terrain characterization, has traditionally focused on the investigation of terrestrial landscapes. However, the dramatic increase in the availability of digital bathymetric data and the increasing ease by which geomorphometry can be investigated using geographic information systems (GISs) and spatial analysis software has prompted interest in employing geomorphometric techniques to investigate the marine environment. Over the last decade or so, a multitude of geomorphometric techniques (e.g. terrain attributes, feature extraction, automated classification) have been applied to characterize seabed terrain from the coastal zone to the deep sea. Geomorphometric techniques are, however, not as varied, nor as extensively applied, in marine as they are in terrestrial environments. This is at least partly due to difficulties associated with capturing, classifying, and validating terrain characteristics underwater. There is, nevertheless, much common ground between terrestrial and marine geomorphometry applications and it is important that, in developing marine geomorphometry, we learn from experiences in terrestrial studies. However, not all terrestrial solutions can be adopted by marine geomorphometric studies since the dynamic, four-dimensional (4-D) nature of the marine environment causes its own issues throughout the geomorphometry workflow. For instance, issues with underwater positioning, variations in sound velocity in the water column affecting acoustic-based mapping, and our inability to directly observe and measure depth and morphological features on the seafloor are all issues specific to the application of geomorphometry in the marine environment. Such issues fuel the need for a dedicated scientific effort in marine geomorphometry.This review aims to highlight the relatively recent growth of marine geomorphometry as a distinct discipline, and offers the first comprehensive overview of marine geomorphometry to date. We address all the five main steps of geomorphometry, from data collection to the application of terrain attributes and features. We focus on how these steps are relevant to marine geomorphometry and also highlight differences and similarities from terrestrial geomorphometry. We conclude with recommendations and reflections on the future of marine geomorphometry. To ensure that geomorphometry is used and developed to its full potential, there is a need to increase awareness of (1) marine geomorphometry amongst scientists already engaged in terrestrial geomorphometry, and of (2) geomorphometry as a science amongst marine scientists with a wide range of backgrounds and experiences.
La utilidad del excedente para el análisis de la información financiera en las sociedades cooperativas
Authors: Cabaleiro Casal María José , Iglesias Malvido Carlos
Published: August 2016

Este trabajo analiza una muestra de sociedades cooperativas gallegas para verificar si es posible inferir diferencias en las conductas financieras de los socios a partir de la cuantía del excedente contable. Con esta finalidad se añade al valor del excedente, el resultado de las variaciones registradas en determinadas partidas contables que incluyen otras rentas residuales. El reparto de dichas rentas revela que los socios no optan generalizadamente por la anticipación completa de las rentas residuales. Se deduce, por tanto, la existencia de empresas que escogen una estrategia de excedente positivo, diferente de la estrategia de excedente nulo planteada por la teoría financiera clásica. En la muestra seleccionada, las diferencias entre ambas estrategias son estadísticamente significativas, lo que abre la puerta, en futuros trabajos, a investigar qué factores pueden explicar la renuncia voluntaria de los socios a la percepción anticipada de todas estas rentas residuales. Tal conducta sólo se evidencia cuando se declara un resultado positivo, de ahí la utilidad del excedente contable en el análisis de la información financiera de la sociedad cooperativa.
Entrepreneurship Development in Micro and Small Enterprises (MSEs) Sector: An assessment of Financial Support Ecosystem
Authors: Bhat Shabir A , Khan Riyaz Ahmad
Published: August 2016

Financial support ecosystem means the availability and access of financial resources to Micro and Small Enterprises Sector and generally includes financial support in terms of consultation support services, government funding support, sufficient government subsidies available for new and growing enterprises, venture capital fund support, adequate financial support schemes available, social investment and other financing resources. Financial Support forms an important contextual environment factor for the establishment, growth and sustenance of the enterprises in Micro and Small Enterprises Sector. Absence of a positive financial support ecosystem has been reported as one of the major constraints for the overall entrepreneurship development in the MSEs Sector throughout the world economies. The present study aims to assess the existing financial support ecosystem for the Micro and Small Enterprises Sector in the state of Jammu and Kashmir against the parameters of sufficient supply of capital / funding, adequate number of financial support schemes, collateral security a big problem for MSEs in availing the finance and access to finance cumbersome due to complex procedures and formalities. And on the basis of the findings suggest measures to improve the financial support ecosystem for the robust entrepreneurship development in Micro and Small Enterprises Sector in the State. Findings indicate that to the extent that the collateral security and procedural hiccups were streamlined and more supply of funds made available, there will be remarkable entrepreneurship development in the MSEs Sector of the State.
Attachment Representations and Maternal Sensitivity in Low Socioeconomic Status Mothers
Authors: Bárrig-Jó Patricia , Nóblega Magaly , Del Prado Juan Nuñez , Conde Gabriela , Carbonell Olga A. , De Litvan Marina Altmann
Published: August 2016

According to attachment theory, mental representations are defined as dynamic cognitive guides that organize both perceptual and behavioral aspects of the self, attachment figure, and relationships with others. Based on this assumption, several studies had reported a relationship between attachment representations and the quality of care provided by mothers to their infants. This study explored on the relationship between maternal attachment representations, assessed by a narrative script task, and the quality of maternal care observed at home. Participants were 32 mothers between 19 and 44 years of age (M = 29.6, SD = 6.28) and their children between 8 and 10 months (M = 8.91, SD = 0.96). The results did not show a significant relationship between global scores of participants’ observed care (i.e., maternal sensitivity) and their attachment representations. However, a specific association was found between two dimensions of sensitivity (acceptance and active/animated interactions) and the narrative script that refers to a child’s physical injury event. Additionally, mothers who reported early separation experiences with their children showed a significant association between sensitivity and attachment representations on mother-child scripts. Moreover, these mothers showed lower scores on global sensitivity and on specific behavioral care dimensions, such as sensitive response and acceptance to child’s signals, than those of mothers that did not report separations early in their children’ lives.
A estratégia como foco em um plano de desenvolvimento de um arranjo produtivo local da região das Missões
Authors: Cardoso Deoclécio , Santos Leandro Dorneles dos , Polacinski Edio
Published: August 2016

Public policies have always been important to the development of remote geographical areas of major production centers. Among several examples of development policies, it stand out the Local Productive Arrangements (APL). In this context, the aim of this paper was to establish a theoretical reflection on strategy, development and APL and present at the same time, a case that is the definition of strategies for the construction of the cluster development plan of family agribusiness Region Missões, Rio Grande do Sul. Through an exploratory study, we sought to thus understand the concepts regarding strategy, development and APL, relating them to the construction of an APL development plan cited, with emphasis on strategies set for their execution. The results indicate the perceived importance of the definition of the strategies as a way of marking for implementation and execution of the cluster development plan, as well as for the development of the Region of Missões.
Proatividade de práticas sustentáveis: uma análise das práticas da empresa Mercur S.A.
Authors: Alves Ana Paula Ferreira , Nascimento Luis Felipe Machado do
Published: August 2016

The adoption of sustainable practices in companies can be analyzed in a continuous, consisting of two extremes: the reactive and proactive response. In this context, sustainable proactivity can be defined as the adoption of actions carried out voluntarily by companies, in order to improve the environmental and social performance and social, beyond legal requirements. A proactive company states their concern and their commitment to society and the environment in which it operates. Given these considerations, this research aims to analyze the voluntary adoption of sustainable practices – sustainable proactivity – of a company. Therefore, a case study was performed with the company Mercur S.A. The results indicate that Mercur can be considered a proactive company, according to the full implementation of actions for sustainability at the core business of the organization and the partial implementation of other practices. Furthermore, the sustainable proactive behavior of Mercur can stimulate their partners, contributing to the introduction of sustainability practices in other companies.
Icons of Beauty: A Suite of Three Women with Ancient Vases from the Workshop of Marcantonio Raimondi
Authors: Rebecchini Guido
Published: August 2016

Working in collaboration with others, Agostino Veneziano produced three
remarkable prints representing nude women seated or standing beside spectacular
allantica vases and set before ruinous landscapes. This article investigates the
authorship and origin of these unusual images. It suggests that the vases are
presented as a metaphor for female beauty, and relates the visual rhetoric of
these three prints to the writings of contemporary writers, including Agnolo
Firenzuola (1493–1543), who described the beauty of women in relation to the
elegant proportions of such vases.
Adaptive learning and decision-making under uncertainty by metaplastic synapses guided by a surprise detection system
Authors: Iigaya Kiyohito
Published: August 2016

Recent experiments have shown that animals and humans have a remarkable ability to adapt their learning rate according to the volatility of the environment. Yet the neural mechanism responsible for such adaptive learning has remained unclear. To fill this gap, we investigated a biophysically inspired, metaplastic synaptic model within the context of a well-studied decision-making network, in which synapses can change their rate of plasticity in addition to their efficacy according to a reward-based learning rule. We found that our model, which assumes that synaptic plasticity is guided by a novel surprise detection system, captures a wide range of key experimental findings and performs as well as a Bayes optimal model, with remarkably little parameter tuning. Our results further demonstrate the computational power of synaptic plasticity, and provide insights into the circuit-level computation which underlies adaptive decision-making.
The hominoid-specific gene TBC1D3 promotes generation of basal neural progenitors and induces cortical folding in mice
Authors: Ju Xiang-Chun , Hou Qiong-Qiong , Sheng Ai-Li , Wu Kong-Yan , Zhou Yang , Jin Ying , Wen Tieqiao , Yang Zhengang , Wang Xiaoqun , Luo Zhen-Ge
Published: August 2016

Cortical expansion and folding are often linked to the evolution of higher intelligence, but molecular and cellular mechanisms underlying cortical folding remain poorly understood. The hominoid-specific gene TBC1D3 undergoes segmental duplications during hominoid evolution, but its role in brain development has not been explored. Here, we found that expression of TBC1D3 in ventricular cortical progenitors of mice via in utero electroporation caused delamination of ventricular radial glia cells (vRGs) and promoted generation of self-renewing basal progenitors with typical morphology of outer radial glia (oRG), which are most abundant in primates. Furthermore, down-regulation of TBC1D3 in cultured human brain slices decreased generation of oRGs. Interestingly, localized oRG proliferation resulting from either in utero electroporation or transgenic expression of TBC1D3, was often found to underlie cortical regions exhibiting folding. Thus, we have identified a hominoid gene that is required for oRG generation in regulating the cortical expansion and folding.
Enhancement of field-effect mobility in molybdenum-disulfide transistor through the treatment of low-power oxygen plasma
Authors: Chen Kuan-Chao , Wu Chong-Rong , Chang Xiang-Rui , Chang Shu-Wei , Lee Si-Chen , Lin Shih-Yen
Published: August 2016

We experimentally demonstrate that the treatment with low-power oxygen plasma can raise the field-effect mobility in molybdenum-sulfide (MoS2) transistors from 0.01 to 9.6 cm2 V−1 s−1, which is an increment of about three orders of magnitude. The decrease in threshold voltage and the increase in the drain current of the devices indicate that the electron density increases significantly after the mild plasma treatment. The emergence of Mo–O characteristics but the suppression of Mo–S features on the X-ray photoelectron spectrum of the plasma-treated sample suggests that a portion of the MoS2 film becomes conductive molybdenum oxide. This transformation may considerably upgrade the performance of MoS2 transistors.
Visible–infrared achromatic imaging by wavefront coding with wide-angle automobile camera
Authors: Ohta Mitsuhiko , Sakita Koichi , Shimano Takeshi , Sugiyama Takashi , Shibasaki Susumu
Published: August 2016

We perform an experiment of achromatic imaging with wavefront coding (WFC) using a wide-angle automobile lens. Our original annular phase mask for WFC was inserted to the lens, for which the difference between the focal positions at 400 nm and at 950 nm is 0.10 mm. We acquired images of objects using a WFC camera with this lens under the conditions of visible and infrared light. As a result, the effect of the removal of the chromatic aberration of the WFC system was successfully determined. Moreover, we fabricated a demonstration set assuming the use of a night vision camera in an automobile and showed the effect of the WFC system.
A horizon scan of future threats and opportunities for pollinators and pollination
Authors: Brown Mark J.F. , Dicks Lynn V. , Paxton Robert J. , Baldock Katherine C.R. , Barron Andrew B. , Chauzat Marie-Pierre , Freitas Breno M. , Goulson Dave , Jepsen Sarina , Kremen Claire , Li Jilian , Neumann Peter , Pattemore David E. , Potts Simon G. , Schweiger Oliver , Seymour Colleen L. , Stout Jane C.
Published: August 2016

Background.Pollinators, which provide the agriculturally and ecologically essential service of pollination, are under threat at a global scale. Habitat loss and homogenisation, pesticides, parasites and pathogens, invasive species, and climate change have been identified as past and current threats to pollinators. Actions to mitigate these threats, e.g., agri-environment schemes and pesticide-use moratoriums, exist, but have largely been applied post-hoc. However, future sustainability of pollinators and the service they provide requires anticipation of potential threats and opportunities before they occur, enabling timely implementation of policy and practice to prevent, rather than mitigate, further pollinator declines.

Methods.Using a horizon scanning approach we identified issues that are likely to impact pollinators, either positively or negatively, over the coming three decades.

Results.Our analysis highlights six high priority, and nine secondary issues. High priorities are: (1) corporate control of global agriculture, (2) novel systemic pesticides, (3) novel RNA viruses, (4) the development of new managed pollinators, (5) more frequent heatwaves and drought under climate change, and (6) the potential positive impact of reduced chemical use on pollinators in non-agricultural settings.

Discussion.While current pollinator management approaches are largely driven by mitigating past impacts, we present opportunities for pre-emptive practice, legislation, and policy to sustainably manage pollinators for future generations.
The core clock genePer1phases molecular and electrical circadian rhythms in SCN neurons
Authors: Jones Jeff R. , McMahon Douglas G.
Published: August 2016

The brain’s biological clock, the suprachiasmatic nucleus (SCN), exhibits endogenous 24-hour rhythms in gene expression and spontaneous firing rate; however, the functional relationship between these neuronal rhythms is not fully understood. Here, we used aPer1::GFP transgenic mouse line that allows for the simultaneous quantification of molecular clock state and firing rate in SCN neurons to examine the relationship between these key components of the circadian clock. We find that there is a stable, phased relationship between E-box-driven clock gene expression and spontaneous firing rate in SCN neurons and that these relationships are independent of light input onto the system or of GABAAreceptor-mediated synaptic activity. Importantly, the concordant phasing of gene and neural rhythms is disrupted in the absence of the homologous clock genePer1, but persists in the absence of the core clock genePer2. These results suggest thatPer1plays a unique, non-redundant role in phasing gene expression and firing rate rhythms in SCN neurons to increase the robustness of cellular timekeeping.
A study of institutional spending on open access publication fees in Germany
Authors: Jahn Najko , Tullney Marco
Published: August 2016

Publication fees as a revenue source for open access publishing hold a prominent place on the agendas of researchers, policy makers, and academic publishers. This study contributes to the evolving empirical basis for funding these charges and examines how much German universities and research organisations spent on open access publication fees. Using self-reported cost data from the Open APC initiative, the analysis focused on the amount that was being spent on publication fees, and compared these expenditure with data from related Austrian (FWF) and UK (Wellcome Trust, Jisc) initiatives, in terms of both size and the proportion of articles being published in fully and hybrid open access journals. We also investigated how thoroughly self-reported articles were indexed in Crossref, a DOI minting agency for scholarly literature, and analysed how the institutional spending was distributed across publishers and journal titles. According to self-reported data from 30 German universities and research organisations between 2005 and 2015, expenditures on open access publication fees increased over the years in Germany and amounted to € 9,627,537 for 7,417 open access journal articles. The average payment was € 1,298, and the median was € 1,231. A total of 94% of the total article volume included in the study was supported in accordance with the price cap of € 2,000, a limit imposed by the Deutsche Forschungsgemeinschaft (DFG) as part of its funding activities for open access funding at German universities. Expenditures varied considerably at the institutional level. There were also differences in how much the institutions spent per journal and publisher. These differences reflect, at least in part, the varying pricing schemes in place including discounted publication fees. With an indexing coverage of 99%, Crossref thoroughly indexed the open access journals articles included in the study. A comparison with the related openly available cost data from Austria and the UK revealed that German universities and research organisations primarily funded articles in fully open access journals. By contrast, articles in hybrid journal accounted for the largest share of spending according to the Austrian and UK data. Fees paid for hybrid journals were on average more expensive than those paid for fully open access journals.
Hepatic Vein Arrival Time for Diagnosis of Liver Cirrhosis
Authors: Abbattista Teresa , Ridolfi Francesco , Consalvo Giovanni Traina , Brunelli Eugenio
Published: August 2016

Objectives

To evaluate the performance of contrast‐enhanced sonography with a second‐generation contrast agent in assessing the severity of chronic diffuse liver disease and differentiating cirrhotic from noncirrhotic liver disease.

Methods

Contrast‐enhanced sonography was performed after intravenous bolus injection of a second‐generation contrast agent in 14 healthy control participants and 160 consecutive patients with cirrhotic and noncirrhotic liver disease (n = 78 and 82, respectively) enrolled between March 2004 and April 2014. The intensity of enhancement in a main hepatic vein was used to determine hepatic vein arrival time, time to peak intensity, and peak contrast enhancement.

Results

The hepatic vein arrival time was lower in cirrhotic patients compared with both noncirrhotic patients and controls (mean ± SD, 15.0 ± 2.8, 21.5 ± 3.4, and 25.6 ± 4.7 seconds, respectively; P < .05). The hepatic vein arrival time in noncirrhotic patients was also significantly lower than that in controls (P < .05). The time to peak intensity was significantly lower in cirrhotic patients compared with noncirrhotic patients and controls (40.7 ± 13.7, 49.4 ± 12.8, and 51.2 ± 13.7 seconds; P < .05). A receiver operating characteristic curve analysis revealed that the hepatic vein arrival time more accurately excluded a diagnosis of liver cirrhosis than the time to peak intensity (area under the receiver operating characteristic curve, 0.953 versus 0.694). Specifically, a hepatic vein arrival time cutoff value of 17 seconds excluded liver cirrhosis with 91.1% sensitivity and 93.6% specificity.

Conclusions

Contrast‐enhanced sonography is a valid alternative method for noninvasive staging of liver diseases. The hepatic vein arrival time could be used to exclude liver cirrhosis in a clinical setting.
Prenatal Diagnosis of an Aortopulmonary Window With an Interrupted Aortic Arch
Authors: García Cecilia , Álvarez Teresa , Bravo Coral , Pérez-Caballero Ramón , Viadero María Teresa , Gámez Francisco , Pérez Ricardo , De León-Luis Juan
Published: August 2016

A prenatal aortopulmonary window with an interrupted aortic arch was detected in a 22‐week‐old fetus. The 3‐vessel and trachea view showed a communication between the ascending aorta and the pulmonary artery. Early postnatal surgery was successful. A PubMed‐based search identified all cases of prenatal aortopulmonary windows between 2002 and 2015. Nine articles were identified. The average gestational age at diagnosis was 28 weeks (range, 22–33 weeks). The most frequent aortopulmonary window was type I (40%). All cases were associated with congenital heart defects, mainly an interrupted aortic arch (50%). No chromosomal or extracardiac abnormalities were seen. Prenatal echocardiography is useful for early diagnosis of an aortopulmonary window. The prognosis depends on the time of surgery and the nature of the associated anomalies.
Prospective Study Comparing Two Second‐Look Ultrasound Techniques
Authors: Kim Yoonsoo , Kang Bong Joo , Kim Sung Hun , Lee Eun Jae
Published: August 2016

Objectives

The aim of this study was to compare the diagnostic performance of handheld ultrasound (US) and an automated breast volume scanner (ABVS) as second‐look US techniques subsequent to preoperative breast magnetic resonance imaging (MRI).

Methods

We prospectively enrolled patients with breast cancer who underwent handheld US and ABVS examinations as second‐look US modalities for additional suspicious lesions found via preoperative breast MRI. We reviewed each second‐look US modality independently and evaluated the detection rate of each modality. We then analyzed the correlation between the detection rate and the MRI factors (size, distance, and enhancement type).

Results

From March to September 2014, both types of second‐look US examinations were performed on 40 patients with breast cancer who had 76 additional suspicious lesions detected via preoperative breast MRI. The detection rate of the ABVS was higher than that of handheld US for the second‐look examination (94.7% versus 86.8%; P< .05). Among the 76 total lesions, 7 were only identified by the ABVS, 1 was only found by handheld US, and 3 were not detected by either the ABVS or handheld US. When we analyzed the correlation between the detection rate and MRI factors, the only meaningful factor was the enhancement type. The ability to detect a nonmass lesion was lower than the ability to detect a mass‐type lesion (P < 0.05) for both the ABVS and handheld US.

Conclusions

For a second‐look US examination subsequent to preoperative breast MRI in patients with breast cancer, the ABVS is a more efficient modality than handheld US for preoperative evaluations. However, both techniques have limitations in detecting nonmass lesions.
Reconstruction of hydrographic changes in the southern Norwegian Sea during the past 135 kyr and the impact of different foraminiferal Mg/Ca cleaning protocols
Authors: Ezat Mohamed M. , Rasmussen Tine L. , Groeneveld Jeroen
Published: August 2016

The shallow subsurface hydrography in the southern Norwegian Sea during the past 135,000 years was investigated using parallel measurements of Mg/Ca and δ18O in shells of the planktic foraminiferal species Neogloboquadrina pachyderma. Two cleaning methods were applied prior to Mg/Ca analysis, “Mg cleaning” and “full cleaning” methods. Different results were obtained, which are most likely due to a more efficient removal of Mn‐contaminant coatings of the shells, when the “full cleaning” procedure was applied. We further combined Mg/Ca and B/Ca from the “full cleaning” method with δ18O values to constrain the calcification temperature and seawater‐δ18O (δ18Osw) in the past. During Heinrich Stadial (HS)1 (∼18.5–15 ka) N. pachyderma constituted >80% of the planktic foraminiferal population, δ18Osw decreased by ∼1.5‰, and shallow subsurface temperature increased by ∼1.5–3°C, suggesting strong stratification in the upper water column and a possible subsurface inflow of Atlantic water below a well‐developed halocline during the calcification seasons of N. pachyderma. Similar decreases in δ18Osw are also recorded for other Heinrich stadials (HS2, 3, 4, 6, and 11). Our temperature estimates confirm previous observations of the delay of the last interglacial “Eemian” warm peak in the eastern Nordic Seas compared to the North Atlantic, and a late warming coinciding with the summer insolation minimum at 60°N. In addition, relatively high values of δ18Osw during the early Eemian suggest a shallow subsurface inflow of Atlantic water below a thin layer of Arctic surface water.
The anomalous change in the QBO in 2015–2016
Authors: Newman P. A. , Coy L. , Pawson S. , Lait L. R.
Published: August 2016

The quasi‐biennial oscillation (QBO) is a tropical lower stratospheric, downward propagating zonal wind variation, with an average period of ~28 months. The QBO has been constantly documented since 1953. Here we describe the evolution of the QBO during the Northern Hemisphere winter of 2015–2016 using radiosonde observations and meteorological reanalyses. Normally, the QBO would show a steady downward propagation of the westerly phase. In 2015–2016, there was an anomalous upward displacement of this westerly phase from ~30 hPa to 15 hPa. These westerlies impinge on or “cutoff” the normal downward propagation of the easterly phase. In addition, easterly winds develop at 40 hPa. Comparisons to tropical wind statistics for the 1953 to present record demonstrate that this 2015–2016 QBO disruption is unprecedented.