bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the Damping Properties of Nanocomposites by Monodispersed Hybrid POSS Nanoparticles: Preparation and Mechanisms
Authors: Wei Wei , Zhang Yingjun , Liu Meihua , Zhang Yifan , Yin Yuan , Gutowski Wojciech Stanislaw , Deng Pengyang , Zheng Chunbai
Published: April 2019

In this work, a series of heptaphenyl siloxane trisilanol/polyhedral oligomeric silsesquioxane (T7-POSS) modified by polyols with different molecular weights were synthesized into liquid-like nanoparticle–organic hybrid materials using the grafted-from method. All grafted POSS nanoparticles changed from solid powders to liquid at room temperature. Polyurethane (PU) nanocomposites with POSS contents ranging from 1.75 to 9.72 wt % were prepared from these liquefied polyols-terminated POSS with polyepichlorohydrin (POSS–PECH). Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the morphology of the POSS–PECH/PU nanocomposites. The results showed that the polyol-terminated POSS particles overcame the nanoagglomeration effect and evenly disperse in the polymeric matrix. The damping factor (tan δ) of resultant nanocomposites increased from 0.90 to 1.16, while the glass transition temperature decreased from 15.8 to 9.4 °C when POSS contents increased from 0 to 9.75 wt %. The gel content, tensile strength and Fourier transform infrared (FTIR) analyses demonstrated that the molecular thermal movement ability of the polyurethane (PU) matrix increased with increasing POSS hybrid content. Therefore, the improvement of the damping properties of the composites was mainly due to the friction-related losses occurring in the interface region between the nanoparticles and the matrix.
Aqueous Liquid-Liquid Phase Separation of Natural and Synthetic Polyguanidiniums
Authors: Prather Leland J. , Weerasekare G. Mahika , Sima Monika , Quinn Colette , Stewart Russell J.
Published: April 2019

Protamines are natural polyguanidiniums, arginine(R)-rich proteins involved in the compaction of chromatin during vertebrate spermatogenesis. Salmine, a protamine isolated from salmon sperm, contains 65 mol% R residues, with positively charged guanidino (Gdm+) sidechains, and no other amino acids with ionizable or aromatic sidechains. Salmine sulfate solutions undergo liquid-liquid phase separation (LLPS) with a concentration-dependent upper critical solution temperature (UCST). The condensed liquid phase comprises 50 wt % water and >600 mg·mL−1 salmine with a constant 1:2 ratio of sulfate (SO42−) to Gdm+. Isothermal titration calorimetry, titrating Na2SO4 into salmine chloride above and below the UCST, allowed isolation of exothermic sulfate binding to salmine chloride from subsequent endothermic condensation and exothermic phase separation events. Synthetic random polyacrylate analogs of salmine, with 3-guanidinopropyl sidechains, displayed similar counterion dependent phase behavior, demonstrating that the LLPS of polyguanidiniums does not depend upon subunit sequence or polymer backbone chirality, and was due entirely to Gdm+ sidechain interactions. The results provide experimental evidence for like-charge pairing of Gdm+ sidechains, and an experimental approach for further characterizing these interactions.
Water/Alcohol Soluble Thickness-Insensitive Hyperbranched Perylene Diimide Electron Transport Layer Improving the Efficiency of Organic Solar Cells
Authors: Zhou Dan , Yang Fei , Qin Yuancheng , Zhong Rong , Xu Haitao , Tong Yongfen , Zhang Yubao , Zhang Qin , Li Mingjun , Xie Yu
Published: April 2019

The electron transport layer (ETL) is very crucial for enhancing the device performance of polymer solar cells (PSCs). Meanwhile, thickness-insensitive and environment-friendly water/alcohol soluble processing are two essential requirements for large-scale roll-to-roll commercial application. Based on this, we designed and synthesized two new n-type ETLs with tetraethylene pentamine or butyl sulfonate sodium substituted tetraethylene pentamine as the branched side chains and high electron affinities perylene diimide (PDI) as the central core, named as PDIPN and PDIPNSO3Na. Encouragingly, both PDIPN and PDIPNSO3Na can effectively reduce the interfacial barrier and improve the interfacial contact. In addition, both of them can exhibit strong n-type self-doping effects, especially the PDIPN with higher density of negative charge. Consequently, compared to bare ITO, the PCE of the devices with ITO/PDIPN and ITO/PDIPNSO3Na ETLs has increased to 3–4 times. Our research results indicate that n-type self-doping PDI-based ETL PDIPN and PDIPNSO3Na could be promising candidates for ETL in environment-friendly water/alcohol soluble processing large-scale PSCs.
Flexural Properties and Fracture Behavior of CF/PEEK in Orthogonal Building Orientation by FDM: Microstructure and Mechanism
Authors: Li Qiushi , Zhao Wei , Li Yongxiang , Yang Weiwei , Wang Gong
Published: April 2019

Fused deposition modeling possesses great advantages in fabricating high performance composites with controllable structural designs. As such, it has attracted attention from medical, automatic, and aerospace fields. In this paper, the influence of short carbon fibers (SCFs) and the orthogonal building orientation on the flexural properties of printed polyether ether ketone (PEEK) composites are systematically studied. The results show that the addition of SCFs raises the uniform nucleation process of PEEK during 3D printing, decreases the layer-to-layer bonding strength, and greatly changes the fracture mode. The flexural strength of vertically printed PEEK and its CF-reinforced composites show strengths that are as high as molded composites. X-ray micro-computed tomography reveals the microstructure of the printed composites and the transformation of pores during bending tests, which provides evidence for the good mechanical properties of the vertically printed composites. The effect of multi-scale factors on the mechanical properties of the composites, such as crystallization in different positions, layer-by-layer bonding, and porosity, provide a successful interpretation of their fracture modes. This work provides a promising and cost-effective method to fabricate 3D printed composites with tailored, orientation-dependent properties.
Data-Driven Interpolation of Sea Level Anomalies Using Analog Data Assimilation
Authors: Lguensat Redouane , Viet Phi Huynh , Sun Miao , Chen Ge , Fenglin Tian , Chapron Bertrand , Fablet Ronan
Published: April 2019

From the recent developments of data-driven methods as a means to better exploit large-scale observation, simulation and reanalysis datasets for solving inverse problems, this study addresses the improvement of the reconstruction of higher-resolution Sea Level Anomaly (SLA) fields using analog strategies. This reconstruction is stated as an analog data assimilation issue, where the analog models rely on patch-based and Empirical Orthogonal Functions (EOF)-based representations to circumvent the curse of dimensionality. We implement an Observation System Simulation Experiment (OSSE) in the South China Sea. The reported results show the relevance of the proposed framework with a significant gain in terms of Root Mean Square Error (RMSE) for scales below 100 km. We further discuss the usefulness of the proposed analog model as a means to exploit high-resolution model simulations for the processing and analysis of current and future satellite-derived altimetric data with regard to conventional interpolation schemes, especially optimal interpolation.
A Data-Driven Approach to Classifying Wave Breaking in Infrared Imagery
Authors: Buscombe Daniel , Carini Roxanne J.
Published: April 2019

We apply deep convolutional neural networks (CNNs) to estimate wave breaking type (e.g., non-breaking, spilling, plunging) from close-range monochrome infrared imagery of the surf zone. Image features are extracted using six popular CNN architectures developed for generic image feature extraction. Logistic regression on these features is then used to classify breaker type. The six CNN-based models are compared without and with augmentation, a process that creates larger training datasets using random image transformations. The simplest model performs optimally, achieving average classification accuracies of 89% and 93%, without and with image augmentation respectively. Without augmentation, average classification accuracies vary substantially with CNN model. With augmentation, sensitivity to model choice is minimized. A class activation analysis reveals the relative importance of image features to a given classification. During its passage, the front face and crest of a spilling breaker are more important than the back face. For a plunging breaker, the crest and back face of the wave are most important, which suggests that CNN-based models utilize the distinctive ‘streak’ temperature patterns observed on the back face of plunging breakers for classification.
Method to Reduce the Bias on Digital Terrain Model and Canopy Height Model from LiDAR Data
Authors: Fradette Marie-Soleil , Leboeuf Antoine , Riopel Martin , Bégin Jean
Published: April 2019

Underestimation of LiDAR heights is widely known but has never been evaluated for several sensors and for diverse types of ecological conditions. This underestimation is mainly linked to the probability of the pulse to reach the ground and the top of vegetation. Main causes of this underestimation are pulse density, pattern of scan (sensors), scan angles, specific contract parameters (flying altitude, pulse repetition frequency) and characteristics of the territory (slopes, stand density and species composition). This study, carried out at a resolution of 1 × 1 m, first assessed the possibility of making an adjustment model to correct the bias of the digital terrain model (DTM), and then proposed a global adjustment model to correct the bias on the canopy height model (CHM). For this study, the bias of both DTM and CHM were calculated by subtracting two LiDAR datasets: high-density pixels with 21 pulses/m² (first return) and more (DTM or CHM reference value pixels) and low-density pixels (DTM or CHM value to correct). After preliminary analyses, it was concluded that the DTM did not need specific adjustment. In contrast, the CHM needed adjustments. Among the variables studied, three were selected for the final CHM adjustment model: the maximum height of the pixel (H2Corr); the density of first returns by m2 (D_first); and the standard deviation of nine maximum heights of the neighborhood cells (H_STD9). The modeling occurred in three steps. The first two steps enabled the determination of significant variables and the shape of the equation to be defined (linear mixed model and non-linear model). The third step made it possible to propose an empirical equation using a non-linear mixed model that can be applied to a 1 × 1 m CHM. The CHM underestimation correction could be used for a preliminary step to several uses of the CHM such as volume calculation, forest growth models or multi-temporal analysis.
Onboard Radio Frequency Interference as the Origin of Inter-Satellite Biases for Microwave Humidity Sounders
Authors: Hans Imke , Burgdorf Martin , Buehler Stefan A.
Published: April 2019

Understanding the causes of inter-satellite biases in climate data records from observations of the Earth is crucial for constructing a consistent time series of the essential climate variables. In this article, we analyse the strong scan- and time-dependent biases observed for the microwave humidity sounders on board the NOAA-16 and NOAA-19 satellites. We find compelling evidence that radio frequency interference (RFI) is the cause of the biases. We also devise a correction scheme for the raw count signals for the instruments to mitigate the effect of RFI. Our results show that the RFI-corrected, recalibrated data exhibit distinctly reduced biases and provide consistent time series.
Combining MODIS and National Land Resource Products to Model Land Cover-Dependent Surface Albedo for Norway
Authors: Bright Ryan M. , Astrup Rasmus
Published: April 2019

Surface albedo is an important physical attribute of the climate system and satellite retrievals are useful for understanding how it varies in time and space. Surface albedo is sensitive to land cover and structure, which can vary considerably within the area comprising the effective spatial resolution of the satellite-based retrieval. This is particularly true for MODIS products and for topographically complex regions, such as Norway, which makes it difficult to separate the environmental drivers (e.g., temperature and snow) from those related to land cover and vegetation structure. In the present study, we employ high resolution datasets of Norwegian land cover and structure to spectrally unmix MODIS surface albedo retrievals (MCD43A3 v6) to study how surface albedo varies with land cover and structure. Such insights are useful for constraining land cover-dependent albedo parameterizations in models employed for regional climate or hydrological research and for developing new empirical models. At the scale of individual land cover types, we found that the monthly surface albedo can be predicted at a high accuracy when given additional information about forest structure, snow cover, and near surface air temperature. Such predictions can provide useful empirical benchmarks for climate model predictions made at the land cover level, which is critical for instilling greater confidence in the albedo-related climate impacts of anthropogenic land use/land cover change (LULCC).
Estimation of Gridded Population and GDP Scenarios with Spatially Explicit Statistical Downscaling
Authors: Murakami Daisuke , Yamagata Yoshiki
Published: April 2019

This study downscales the population and gross domestic product (GDP) scenarios given under Shared Socioeconomic Pathways (SSPs) into 0.5-degree grids. Our downscale approach has the following features. (i) It explicitly considers spatial and socioeconomic interactions among cities, (ii) it utilizes auxiliary variables, including road network and land cover, (iii) it endogenously estimates the influence from each factor by a model ensemble approach, and (iv) it allows us to control urban shrinkage/dispersion depending on SSPs. It is confirmed that our downscaling results are consistent with scenario assumptions (e.g., concentration in SSP1 and dispersion in SSP3). Besides, while existing grid-level scenarios tend to have overly-smoothed population distributions in nonurban areas, ours does not suffer from the problem, and captures the difference in urban and nonurban areas in a more reasonable manner. Our gridded dataset, including population counts and gross productivities by 0.5 degree grids by 10 years, are available from http://www.cger.nies.go.jp/gcp/population-and-gdp.html.
On the Use of Satellite Imagery and GIS Tools to Detect and Characterize the Urbanization around Heritage Sites: The Case Studies of the Catacombs of Mustafa Kamel in Alexandria, Egypt and the Aragonese Castle in Baia, Italy
Authors: Elfadaly Abdelaziz , Lasaponara Rosa
Published: April 2019

The sustainable development of urban growth is a mandatory challenge to be addressed, as also highlighted in the Agenda 2030, and this requires suitable and sustainable planning strategies, as well as systematic and timely monitoring of urban expansion and its effects. In this context, satellite data (today also available free of charge) can provide both (i) historical time-series datasets, and (ii) timely updated information related to the current urban spatial structure and city edges, as well as parameters to assess urban features and their statistical characterization to better understand and manage the phenomenon. Nevertheless, it is important to highlight that the identification and mapping of urban areas is still today a complex challenge, due to the heterogeneities of materials, complexity of the features, etc. Our approach, herein adopted, addresses the challenges in using heterogeneous data from multiple data sources for change detection analysis to improve knowledge and monitoring of landscape over time with a specific focus on urban sprawl and land-use change around cultural properties and archaeological areas. Two significant test cases were selected: (i) one in Egypt, the Catacombs of Mustafa Kamel in Alexandria, and (ii) one in Italy, the Aragonese Castle in Baia–Naples. For both study areas, the changes in urban layers were identified over time from satellite data and investigated using spatial analytic tools to statistically characterize them. The results of this study showed that (i) the increase in urban areas is the main phenomenon around both heritage areas, (ii) this increase is sharper in developing countries (e.g., Egypt) than developed countries (e.g., Italy), (iii) the methodology herein adopted is suitable for both big and small urban changes as observed around the Catacombs of Mustafa Kamel and the Aragonese Castle.
Who Benefits from CAP? The Way the Direct Payments System Impacts Socioeconomic Sustainability of Small Farms
Authors: Volkov Artiom , Balezentis Tomas , Morkunas Mangirdas , Streimikiene Dalia
Published: April 2019

The effects of globalization have often been adverse for the agricultural sector, especially its most vulnerable element—the small farm. The importance of the agricultural sector as a whole and small farms in the sense of ensuring food security, employment and viability of rural areas, implies a necessity to support the sector and small farms in particular. For this purpose, the Common Agricultural Policy (CAP) of the European Union (EU) seeks to boost the sustainability of agriculture in multiple dimensions. The 2013 reform of the CAP has provided a particularly strong impetus towards this direction. This paper establishes an indicator system to quantify the effects of the CAP direct payments on the socioeconomic sustainability of small farms. Expert survey and multi-criteria assessment are used to this end. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method is applied for the multi-criteria analysis. Lithuania is taken as a case study. The results show that, in the case of Lithuania, the direct payment system did not contribute to the improvement in socioeconomic sustainability of small farms up until 2013 CAP reform when its impact became undeniable.
Spatio-Temporal Variation in Mountainous Landscape Changes: A Case Study of Shizhu County
Authors: Chen Qin , Li Yuechen , Liu Chunxia , Yang Yunong , Wu Jiao , Li Mingyang
Published: April 2019

The study of dynamic changes and spatial variation of landscape patterns is important to deeply understand the relationship between human activities and the natural environment. We selected a typical mountain area, Shizhu County, as the study area and analyzed the landscape’s dynamic changes and spatial variation in that area from 2000–2015. The results showed that cropland and forestland were the dominant landscape types in the study area. Cropland and grassland areas decreased, being mainly converted to forestland. Forestland and built-up land areas were increasing; the increase in built-up land was mainly due to the invasion into cropland areas, and the increase in forestland was mainly due to the conversion of cropland and grassland. Water bodies were affected by factors such as water storage in the Three Gorges Reservoir, and their area continued to increase. The change in landscape was most dramatic from 2005–2010, mainly due to the rapid increase in the areas of built-up land and water bodies and the rapid decrease in grassland area. There were apparent spatial variations in landscape distribution, patterns, and dynamic changes. Although water bodies were mainly distributed in the relatively gentle slope areas with an elevation of less than 200 m and a slope of 0°–6°, other landscapes were concentrated at an elevation higher than 500 m, a slope of 15°–35°, with a westerly or northwesterly aspect. These areas also had the most drastic landscape changes. At the type-level and the landscape-level, landscape indices showed greater variation with elevation and slope than with aspect. Finally, the variations with elevation, slope, and aspect differed among different landscape types.
A Regional Comparison of Factors Affecting Global Sorghum Production: The Case of North America, Asia and Africa’s Sahel
Authors: Mundia Clara W. , Secchi Silvia , Akamani Kofi , Wang Guangxing
Published: April 2019

Understanding the dynamics of food production is critical to improving food security. This is particularly important in regions that rely on subsistence agriculture with little adaptive capacity to climate change. Sorghum plays an important role in food security in some of the poorest parts of the world. This article reviews the literature to identify and examine the major factors affecting sorghum production in three major production regions. Factors were not categorized ex ante but rather determined from the review. Ten major factors were identified as having notable impacts on sorghum production: climate change, population growth/economic development, non-food demand, agricultural inputs, demand for other crops, agricultural resources scarcity, biodiversity, cultural influence, price and armed conflict. This synthesis revealed that (1) multiple factors simultaneously affect sorghum production; (2) the effect of each factor is greatly influenced by the magnitude and certainty of one or more other factors; and, (3) factors differ in relevance and degree with regard to geography. Generally, improved agricultural inputs, population growth/economic development and climate change have substantial influence on sorghum production. However, local dynamics likely go beyond these broad trends and more exhaustive, locally-focused studies are needed for actionable planning purposes.
Facing Climate Change: What Drives Internal Migration Decisions in the Karst Rocky Regions of Southwest China
Authors: Shi Guoqing , LYU Qiulong , Shangguan Ziheng , Jiang Tianhe
Published: April 2019

Global climate change and its influence on human migration have caused heated debates. There is no consensus about the role of environmental change in shaping migration decisions. To amass more evidence and develop a deeper understanding of the relations between the environment and migration, this paper seeks to evaluate the importance of various drivers (economic, social, political, demographic, and environmental drivers) and determine the internal mechanism in the decision process. The Likert scale was used as the tool for measuring each respondent’s perception of the drivers, and the within-group interrater agreement index was used to express the survey data and to select the actual driving forces. As a result, economic, social, and political factors were strong forces that promoted migration directly, while demographic and environmental factors were moderate or weak forces that promoted migration indirectly. The migrants’ core consideration was to effectively reduce family risks and sustain their livelihoods by moving to a destination to improve their household income, keep their original social networks, and obtain housing allowances from the local government. Land degradation and meteorological disasters were rooted in the vulnerability and risks of a family, and these factors indirectly influenced the people’s decisions by affecting the socioeconomic drivers. We concluded that isolating the environmental drivers from other drivers underlying migration decisions is difficult. Additionally, the internal mechanism indicated that both environmental and non-environmental factors all have an impact on choice in different ways. Future policies should be aimed at increasing sustainable livelihoods and the social resilience of migrant families at a personal level, balancing the development levels of the original locations and destinations, and strengthening international cooperation to reduce the negative effects of climate change at the regional level.
Governance Challenges in Addressing Climatic Concerns in Coastal Asia and Africa
Authors: Hossen M. Anwar , Chowdhury Md. Arif , Hans Asha , Tagoe Cynthia Addoquaye , Allan Andrew , Nelson Winfred , Patel Amrita , Mondal M. Shahjahan , Salehin Mashfiqus , Quaye Ruth M. , Das Shouvik
Published: April 2019

Coastal people, especially those living within deltaic areas, encounter major climatic concerns which affect their livelihoods. To cope with this problem, different types of planned adaptation strategies have been implemented guided by laws, policies and programs. However, these guiding documents sometimes fall short of addressing the needs of climate-affected people, especially in natural resource-dependent societies in Asia and Africa. Based on this premise, this paper sought to evaluate the effectiveness of existing policy documents which affect the lives of people living in one large delta (Ganges-Brahmaputra-Meghna in Bangladesh), two medium-sized deltas (Indian Bengal delta—part of the Ganges-Brahmaputra-Meghna and Mahanadi in India), and a small-sized delta (Volta in Ghana). The study followed a mixed methods research design, which included desktop analyses of policies, laws and programs, a questionnaire survey conducted among individuals who played various roles in the policy and legal development processes at national and local levels and focus group discussions at the community level in the three countries. National laws, policies and programs were assessed in the context of climate change adaptation through three lenses: human rights, natural resource management and disaster response. Findings of this paper reveal that the existing documents have some strengths to promote adaptation, although they have some major limitations that cause concerns among the delta communities.
Mathematical Modeling of a Class of Symmetrical Islamic Design
Authors: Zahri Mostafa
Published: April 2019

In this paper, we present a new model for simulating an interesting class of Islamic design. Based on periodic sequences on the one-dimensional manifolds, and from emerging numbers, we construct closed graphs with edges on the unit circle. These graphs build very nice shapes and lead to a symmetrical class of geometric patterns of so-called Islamic design. Moreover, we mathematically characterize and analyze some convergence properties of the used up-down sequences. Finally, four planar type of patterns are simulated.
An Efficient Class of Traub-Steffensen-Like Seventh Order Multiple-Root Solvers with Applications
Authors: Sharma Janak Raj , Kumar Deepak , Argyros Ioannis K.
Published: April 2019

Many higher order multiple-root solvers that require derivative evaluations are available in literature. Contrary to this, higher order multiple-root solvers without derivatives are difficult to obtain, and therefore, such techniques are yet to be achieved. Motivated by this fact, we focus on developing a new family of higher order derivative-free solvers for computing multiple zeros by using a simple approach. The stability of the techniques is checked through complex geometry shown by drawing basins of attraction. Applicability is demonstrated on practical problems, which illustrates the efficient convergence behavior. Moreover, the comparison of numerical results shows that the proposed derivative-free techniques are good competitors of the existing techniques that require derivative evaluations in the iteration.
A Combined Field and Numerical Modeling Study to Assess the Longitudinal Channel Slope Evolution in a Mixed Alluvial and Soft Bedrock Stream
Authors: Wu Kuowei , Yeh Keh-Chia , Lai Yong G.
Published: April 2019

A study approach is developed to assess the longitudinal channel slope under the equilibrium condition as well as the transient evolution of a mixed alluvial-soft-bedrock stream. Both the historical field data and 2D mobile-bed numerical modeling are adopted. The proposed approach is applied to a 14 km reach downstream of the Ji-Ji Weir, Chuo-Shui River, Taiwan, where continuous maintenance works have been carried out to stabilize this reach. In this study, the temporal evolution of the longitudinal channel profile is assessed numerically with three spatial scales: The large (the entire study reach), the medium (four sub-reaches), and the local (cross-sections) scale. The large scale analysis is the approach for purely alluvial streams and is shown to be difficult to use to characterize mixed alluvial-bedrock streams. The local scale analysis shows that the soft-bedrock incision has a widely fluctuating slope, reflecting the compound environmental forcing and complex riverbed setting. With the medium scale analysis, the longitudinal channel profile is found to follow a predictive trend if the reach is partitioned into four distinctive sub-reaches. Characteristics of the dynamic channel slope evolution in different spatial scales are computed and presented. The study results can be used to select the proper locations and types of the engineering stabilizing structures in a mixed alluvial and soft bedrock stream.
Analysis of the Mixing Processes in a Shallow Subtropical Reservoir and Their Effects on Dissolved Organic Matter
Authors: Wang Xinchen , Zhang Hong , Bertone Edoardo , Stewart Rodney A. , O’Halloran Kelvin
Published: April 2019

A good understanding of the physical processes of lakes or reservoirs, especially of those providing drinking water to residents, plays a vital role in water management. In this study, the water circulation and mixing processes occurring in the shallow, subtropical Tingalpa Reservoir in Australia have been investigated. Bathymetrical, meteorological, chemical and physical data collected from field measurements, laboratory analysis of water sampling and an in-situ Vertical Profile System (VPS) were analysed. Based on the high-frequency VPS dataset, a 1D model was developed to provide information for vertical transport and mixing processes. The results show that persistent high air temperature and stable reservoir water depth lead to a prolonged thermal stratification. Analysis indicates that heavy rainfalls have a significant impact on water quality when the dam level is low. The peak value of Dissolved Organic Carbon (DOC) concentration occurred in the wet season, while the specific UV absorbance (SUVA) value decreased when solar radiation increased from spring to summer. The study aims to provide a comprehensive approach for understanding and modelling the water mixing processes in similar lakes with high-frequency data from VPS’s or other monitoring systems.
Improved Approach for the Investigation of Submarine Groundwater Discharge by Means of Radon Mapping and Radon Mass Balancing
Authors: Schubert Michael , Petermann Eric , Stollberg Reiner , Gebel Micha , Scholten Jan , Knöller Kay , Lorz Carsten , Glück Franziska , Riemann Kornelius , Weiß Holger
Published: April 2019

The paper presents an improved approach for investigating submarine groundwater discharge (SGD) based on radon mapping and radon mass balancing in the coastal sea. While the use of radon as an environmental tracer in SGD studies is well-established, we identified based on our longstanding experience six methodical shortcomings of the conventional approach and suggest corresponding developments. The shortcomings include: (1 and 2) inadequate consideration of both detection equipment response delay and influence of tidal stage; (3 and 4) incorrect quantification of radon losses, due to offshore mixing and degassing resulting in a potentially incorrect radon mass balance; (5) inaccurate determination of the terrestrial groundwater endmember, due to inhomogeneous radon distribution in the coastal aquifer; and (6) difficulties in distinguishing between discharged fresh groundwater and recirculated seawater. The improved approach is practically demonstrated in a step by step manner in a large-scale field study, which was carried out in False Bay (South Africa) and which consisted of two parts, namely (i) qualitative SGD localization along the entire False Bay coastline based on coastal radon distribution patterns and (ii) quantitative SGD investigation within a defined coastal area of interest (AOI) based on a radon mass balance (RMB). The plausibility of the AOI related results was evaluated by a hydrogeological model, used for qualitative SGD localization, and a hydrological model, applied for estimating groundwater recharge within the AOI catchment.
Zonificación de unidades de paisaje en la cuenca del río Khora Tiquipaya (Quillacollo, Bolivia) sustentada en el enfoque de ecología del paisaje
Authors: Reyna-Bowen Lizardo , Reyna-Bowen Mauricio , Reina-Castro José , Hurtado Ernesto
Published: April 2019

La mayor parte de las cuencas de la región del Valle Central de Cochabamba (Bolivia) presenta erosión de suelo; escasa cobertura vegetal y períodos de lluvia intensa y de corta duración que ocasionalmente generan crecidas de ríos violentas de escorrentías que, como consecuencia directa, producen desastres que afectan a la infraestructura urbana y rural. El objetivo del presente trabajo fue zonificar los aspectos biofísicos de la cuenca Khora Tiquipaya, empleando imágenes satelitales, modelo digital de elevación (MDE), mapa de pendientes, y de relieve. Se describieron los perfiles de suelos siguiendo el modelo USDA y FAO.  Las muestras se analizaron químicamente in situ. Luego del procesamiento de la información se lograron los siguientes resultados: 1) identificación de formaciones geológicas, tipos de depósitos, deslizamientos, relieves, taxonomía del suelo, cobertura y uso; 2) determinación del área de las unidades de paisaje en ha; y 3) formulación de una propuesta de manejo sostenible para la cuenca. La utilización de estas herramientas contribuye significativamente a la interpretación en grandes superficies de estudio, optimizando recursos y tiempo, para la gestión adecuada de la toma de decisiones en un contexto de desarrollo sostenible deseado.
Tendencias de la elaboración de proyectos personales de vida para la orientación vocacional en el Ecuador
Authors: Mendoza Cedeño Isaac Geovanni , Machado Ramírez Evelio Felipe
Published: April 2019

El presente artículo tiene como propósito desarrollar un estudio de las tendencias acerca de la elaboración de proyectos personales de vida como vía para la orientación vocacional en la República del Ecuador. Por tal motivo se ofrece una descripción, un análisis crítico de las prácticas actuales, sus principios fundacionales asumidos desde diferentes perspectivas y contextos educativos y sociales latinoamericanos, lo cual posee relevancia en la construcción de una propuesta educativa vocacional que contribuya eficientemente en los procesos de elaboración de los proyectos personales de vida; así como las tendencias subyacentes en el país.

Palabras claves: contexto, desarrollo integral, perspectivas, realización personal, toma de decisiones.
Anidación de tortugas marinas en la provincia de Manabí, Ecuador
Authors: Mizobe Alcívar Cyntia , Contreras López Manuel
Published: April 2019

A partir de una interpretación de imágenes satelitales se identifican 69 playas de arena que reúnen las condiciones para la anidación de tortugas marinas a lo largo del litoral continental de la provincia de Manabí. Posteriormente se realizó una búsqueda bibliográfica extendida a información gris sobre antecedentes de anidación en el área de estudio, desde 1968 a enero de 2014. Los antecedentes bibliográficos se complementan con avistamientos inéditos de arribos y el registro de más de 500 nidos. Fue necesario confeccionar un listado con los nombres de las playas de arena del litoral de Manabí. Se pudo comprobar que 22 sitios identificados con un total de 32 km de longitud, son efectivamente de anidación al menos de Eretmochelys imbricata (carey), Chelonia mydas (verde) y Lepidochelys olivacea(golfina), las únicas tres especies cuya anidación es confirmada en la provincia. Además se discute la posible anidación de Dermochelys coriacea (laúd). No se registra el comportamiento de arribadas de Lepidochelys olivacea, sin embargo, la frecuencia con que ocurre la anidación es relevante. 

Palabras clave: Playas de Arena, Dermochelys coriacea, Eretmochelys imbricata, Chelonia mydas, Lepidochelys olivacea
Inducción al desove de la Concha Prieta Anadara tuberculosa (Sowerby, 1833) en condiciones de laboratorio
Authors: Retamales González Roberto , Panta Vélez Patricio , Vélez Cárdenas José
Published: April 2019

El objetivo de esta investigación fue inducir el desove de la Anadara tuberculosa mediante la disminución y aumento de salinidad en condiciones de laboratorio. Los reproductores de estos moluscos se recolectaron en el sitio San Felipe, del cantón San Vicente, en octubre de 2012. Se describe el desarrollo embrionario y larvario de este molusco, obteniendo larva tipo D entre las 16 y 18 horas después del desove. Durante los 17 días del cultivo larvario, las larvas fueron alimentadas con una mezcla de microalgas de Chaetoceros gracilis e Isochrysis galbana, logrando una tasa de crecimiento de 4,755 µm/día. El desarrollo embrionario y larvario de la A. tuberculosa es semejante a las otras especies de moluscos bivalvos. La contaminación por protozoarios y bacteriana fue uno de los principales factores de mortalidad de las larvas, limitando la fase final del cultivo larvario.

Palabras clave: Anadara tuberculosa, desarrollo embrionario, cultivo larval, crecimiento, salinidad.
Tendencias en la variabilidad de la temperatura superficial del mar en la costa de Ecuador
Authors: Ruperti Hans , Carroll Dustin , Breaker Larry
Published: April 2019

Datos  de  temperatura superficial  del  mar  de  siete  regiones adyacentes (Boxes) que abarcan la costa de Ecuador han sido examinados en busca de tenencias a largo plazo y características relacionadas. El área de estudio se extiende desde los 84°W y entre las latitudes 4° S a 2° N. La información fue promediada mensualmente cubriendo un período comprendido entre los años 1900 hasta 2014. La temperatura superficial del mar  generalmente en  Ecuador aumenta hacia la costa y disminuye hacia  el sur. Se identifican los principales eventos de calentamiento de “El Niño Oscilación del Sur”, en  particular  los  ocurridos  entre  1982-1983  y  1997-1998. En la mayoría de los casos las tendencias muestran que la temperatura superficial   del  mar aumentó más   rápidamente durante los primeros años de los registros que durante los años posteriores.

Palabras clave: Variabilidad de la TSM, ENOS, Descomposición de modo empírico, Regresión Lowess, Ecosistemas marinos.
Variabilidad genética de la colección de piñón (Jatropha Curcas L.) del Instituto Nacional de Investigaciones Agropecuarias del Ecuador, usando marcadores tipo microsatélites
Authors: Mendoza Heriberto , Mendoza Javier , López Julio , Mejía Nelly , Zambrano Freddy , Mendoza María , Ponce Wilmer
Published: April 2019

Para conocer la diversidad genética del piñón (Jatropha curcas L.) existente en Ecuador, se realizó un estudio mediante el uso de marcadores moleculares tipo microsatélites. Fue analizada la variabilidad genética de la colección del Instituto Nacional de Investigaciones Agropecuarias (INIAP) conformada por 158 accesiones, de las cuales 151 fueron colectadas en seis provincias del Ecuador, 4 provinieron de Perú y 3 de Brasil. Como muestras para el estudio se tomaron 15 gramos de brotes tiernos de una planta de cada accesión y se mantuvieron en 50 gramos de sílica gel para su secamiento. Una vez secas, las muestras se maceraron con una solución de metabisulfito de sodio como antioxidante y se almacenaron a temperatura ambiente hasta la extracción del ADN genómico. De los 10 primers SSRs analizados, solo dos mostraron patrones polimórficos o informativos (J-26 y J-28), evidenciando la formación de dos grupos genéticos principales y dos subgrupos. Se determinó que la variabilidad entre genotipos multilocus fue del 13,92%, representada en 22 grupos de accesiones. Los genotipos 20 y 21 presentaron 44,30% y 15,82% de accesiones duplicadas.

Palabras clave: Caracterización, Germoplasma, Genética, Genotipo, Jatropha.
Respuesta en plántulas de Leucaena a la imbibición de las semillas con lixiviado de pseudotallo de plátano
Authors: Borges Duran Jorge Alejandro , Quiróz Rodríguez Yannelly Milagro , Becerra Falcón Beatriz Elena , Sánchez López Darwin José
Published: April 2019

Response in Leucaena seedlings to the seeds imbibition of pseudostems plantain leached

Resumen

La L. leucocephala es una leguminosa forrajera arbórea utilizada para la alimentación de rumiantes; sin embargo, su lento crecimiento inicial tiende a limitar su supervivencia durante su establecimiento. Por tal razón, se planteó evaluar la respuesta en plántulas a la previa imbibición de las semillas con lixiviado de pseudotallo de plátano a concentraciones de 0, 10, 25, 50, 75 y 100%, durante 12 horas y posterior siembra en bandejas con sustrato inerte, bajo condiciones de sombra parcial, en un diseño experimental completamente aleatorio. A los 30 días post-germinación se evaluaron variables morfológicas, analizando los datos obtenidos mediante ANAVAR y comparación de medias por Tukey. Las plántulas emergidas de semillas tratadas con LSP-10% presentaron una mayor altura (14,5 cm), longitud de raíz (13,2 cm) y número de hojas (14), siendo diferentes al resto de los tratamientos. El diámetro del tallo y la MS acumulada no resultaron afectados por la imbibición, siendo en promedio de 1,16 cm y 33%, respectivamente. En general, las respuestas se manifestaron mayormente en los puntos de crecimiento foliar y radical, reforzando la hipótesis sobre la presencia de compuestos auxínicos en el lixiviado que pudieron estimular una rápida diferenciación y proliferación celular en el tejido meristemático apical.

Palabras clave: Leucaena leucocephala (Lam.) de Wit; establecimiento; promotor de crecimiento; compuestos auxínicos.

Abstract

Leucocephala is an arboreal forage legume used to feed ruminants; however, its initial slow growth tends to limit its survival during its establishment. For this reason, it was proposed to evaluate the response in seedlings to the previous imbibition of seeds with pseudostem plantain leached at concentrations of 0, 10, 25, 50, 75 and 100%, for 12 hours and then sowing in trays with inert substrate, under conditions of partial shade, in a completely randomized experimental design. After 30 days post-germination morphological variables were evaluated, analyzing the data obtained by means of ANAVAR and comparison of means by Tukey. The seedlings emerged from seeds treated with LSP-10% had a higher height (14,5 cm), root length (13,2 cm) and number of leaves (14), being different from the rest of the treatments. The diameter of the stem and the accumulated MS were not affected by the imbibition, being on average of 1.16 cm and 33%, respectively. In general, the responses were manifested mainly in the points of foliar and radical growth, reinforcing the hypothesis about the presence of auxin compounds in the leachate that could stimulate rapid cell differentiation and proliferation in the apical meristematic tissue.

Keywords: Leucaena leucocephala (Lam.) de Wit; establishment; growth promoter; auxin compound.
Aplicación foliar de micronutrientes y fitorreguladores como complemento de la fertilización edáfica en maíz amarillo duro
Authors: Cedeño Sacón Frowen , Cargua Chávez Jessica , Cedeño Dueñas Jairo , Mendoza Vargas Javier , López Álava Geoconda , Cedeño García Galo Alexander
Published: April 2019

Foliar application of micronutrients and phytoregulators as complement of the edaphic fertilization in hard yellow corn

Resumen

El objetivo de la investigación fue determinar efecto de la nutrición foliar complementada con micronutrientes y fitorreguladores sobre el rendimiento del maíz amarrillo duro. Los tratamientos fueron: T1) fertilización edáfica + nutrición foliar complementada con micronutrientes y fitorreguladores, y T2) fertilización edáfica sin nutrición foliar complementaria. La aplicación foliar fue realizada en las etapas fenológicas V6 (hoja 6), V12 (hoja 12) y V18 (hoja 18). La comparación entre tratamientos se hizo a través de la prueba de “t de Student” para muestras pareadas con ocho parcelas por tratamiento y un nivel de confianza del 95%. La principal variable evaluada fue el rendimiento en t ha-1. La nutrición foliar complementada con micronutrientes y fitorreguladores mostró efectos significativos (p≤0,05) sobre el rendimiento, que en promedio produjo 11,27 t ha-1 en relación al tratamiento testigo (fertilización edáfica) con un rendimiento de 8,77 t ha-1, lo cual representó un 28% de incremento productivo. Los resultados alcanzados fueron muy prometedores y destacan la importancia de la nutrición foliar complementaria dentro de un plan integral de manejo del cultivo, sin embargo, no son definitivos, por lo que es necesario realizar ajustes vía experimentos formales en varias localidades para precisar datos y recomendaciones.

Palabras clave: Fertilizantes; Nutrición de las plantas; Producción agrícola.

Abstract

The objective of this research was to determine the effect of foliar nutrition supplemented with micronutrients and phytoregulators on the yield of hard yellow corn. The treatments were: T1) edaphic fertilization + foliar nutrition supplemented with micronutrients and phytoregulators, and T2) edaphic fertilization without supplementary foliar nutrition. Foliar application was carried out in the phenological stages V6 (leaf 6), V12 (leaf 12) and V18 (leaf 18). The comparison between treatments was done through the “t Student” test for paired samples with eight plots per treatment and a 95% confidence level. The main variable evaluated was the yield in t.ha-1. Foliar nutrition supplemented with micronutrients and phytoregulators showed significant effects (p≤0,05) on yield, which on average produced 11,67 t ha-1 in relation to control treatment (edaphic fertilization) with a yield of 8,77 t ha-1, wich represented a 28% increase in production. The results obtained were very promising and highlight the importance of supplementary foliar nutrition within an integrated plan of crop management; however, they are not definitive, so it is necessary to make adjustments through formal experiments in several locations to specify data and recommendations.

Keywords:  Agricultural production; Fertilizers; Plant nutrition.