bluuebunny/crossref_metadata_2025 huggingface dataset:
Quality of Life among Haemophilic Children in Central Madhya Pradesh, India: A Cross-sectional Study
Authors: Tejwani Madhuri , Pal Pankaj , Prajapati Gaurav Kumar , Thakur Vipin , Sharma Shweta
Published: August 2024

Introduction: Quality of Life (QoL) has recently become a focus of research in haemophilia, as children with haemophilia miss out on opportunities to reach their full potential during school and later in life. This leads to emotional and behavioural problems, family issues, and a decrease in Health-related Quality of Life (HRQoL). There is very limited data from the state of Madhya Pradesh, India, to assess the QoL in haemophilia patients. Aim: To study the clinical profile of haemophilic children and assess their QoL. Materials and Methods: The present hospital-based crosssectional study was conducted in the Department of Paediatrics, Gandhi Medical College, Bhopal, Madhya Pradesh, India, from January 2019 to December 2019. A total of 49 children (Institutional incidence), aged from 4-12 years, with factor VIII/ IX deficiency who presented in the Paediatric ward of the study Institution for factor transfusion, were included in the study. The study population was divided into two groups with children aged (group ) and children aged 8-12 years (group II). A detailed clinical history was obtained from the accompanying parent/guardian, and QoL was measured using the Haemophilia QoL (Haemo-QoL) questionnaire. Scores achieved in each dimension, as well as, the total score were combined on a scale ranging from 0 to 100. High values indicate high impairment in QoL. The meanings of different scales like Standardised and Transformed Scale Scores (TSS) of Haemo-QoL were analysed using the student’s t-test. Results: In the present study, haemophilia A was more common than haemophilia B. All patients who attended the paediatric ward for factor transfusion were males, with a mean age of 8.37±2.56 years. It was also observed that the proportion of patients who were diagnosed early was significantly higher in the 4-7 years age group compared to the 8-12 years age group of patients (p-value<0.05). The present study revealed that the mean overall scores on the Haemo-QoL for the age groups 4-7 years and 8-12 years were 41.92±17.95 and 51.84±16.36, respectively. The highest impairment was in the physical health, school and sports, and family dimensions of QoL. Conclusion: The QoL is poor among children in both age groups. The current study also showed that as age advances, the QoL of haemophilia patients becomes poorer.
Plant Growth and Yield Dynamics in Tomato Cultivation: Insights from Front Line Demonstrations
Authors: Rai A. K. , Panda S. , Panda T.C. , Mishra P.J. , Phonglosa A. , Rai A.
Published: August 2024

The present study was undertaken to assess the yield gap through Front Line Demonstrations (FLDs) on tomato crops. Krishi Vigyan Kendra, Malkangiri (Odisha), conducted 13 trials on tomatoes in 2015-16 and 2016-17 across different villages. The predominant grower practices were treated as controls, while recommended practices were implemented in demonstration fields. Over the two years, the average yield in the demonstration fields was 622.3 quintals per hectare (q/ha), compared to 305.2 q/ha in the control fields. The average technology gap, representing the difference between potential and actual yields in the demonstration fields, was found to be 377.7 q/ha. The technology index, indicating the percentage deviation from potential yield achieved averaged 37.77%.
Student Engagement in the Online Learning Environment during the COVID-19 Pandemic in Sri Lanka
Authors: Wijetunga Chatura Sewwandi
Published: August 2024

Aims: This study focuses on factors affecting students’ engagement, and their issues and perceptions of online education in Agricultural Economics and Agribusiness Management related curricula in Sri Lankan state universities during the COVID-19 pandemic.
Place and Duration of the Study: Data were collected from university undergraduates who studied Agricultural Economics and Agribusiness Management subjects in six state universities in Sri Lanka from January 2022 to February 2022.
Methodology: The primary data were collected from 215 university undergraduates in relevant discipline through a pre-tested questionnaire developed by the researcher via Google form. All the respondents were volunteered to complete the questionnaire and submitted their responses online and those responses were collected anonymously. The Factor analysis was employed in the study to generate a single value for the dependent variable and the multiple linear regression was used to understand the factors affecting Student engagement in online learning.
Results: The study indicates that the majority of students showed a positive attitude toward online education. The study findings show the student-teacher interaction is a positive and significant factor in online education in Agricultural Economics and Agribusiness Management disciplines but student-to-student interaction is not a significant factor for student engagement in online education. Moreover, when the students are female and students are in their final year, they are most likely to engage in online education. The study also shows that the majority of students prefer online education even though some highlighted the negative issues. However, providing continuous and stable access to the internet connection and providing other infrastructure facilities to students and teachers are some of the main challenges in promoting online education in Sri Lanka. In addition, proper attention should be paid to assure the quality of online education to develop students holistically.
Conclusion: Study concludes that building and maintaining student-teacher interaction is one of the key determinants in student engagement in online education. Also student engagement can be enhanced through a student-centered learning activities which focus on their active contribution.
Implementation of Catch-Up Fridays: A Case Study on Teachers' Experiences at the Davao Del Norte Division
Authors: Requillo Diocyl Ann C. , Flores Loyd C. , Calizo Ellaine V. , Legarda Maricris B. , Almagro Ronald E. , Gonio Yvette G. , Manguiob Ivy D. , Pamor Ivy L. , Lagura Glenne B.
Published: August 2024

The study focuses on the implementation of the "Catch-Up Fridays" program in the Davao del Norte Division, Philippines, aimed at addressing learning gaps among students exacerbated by the COVID-19 pandemic. Initiated by the Department of Education (DepEd), this program dedicates every Friday to reading and writing activities, values, peace, and health education to enhance students' academic and holistic development. Despite its noble intentions, the program faces challenges in execution, notably in the provision of adequate resources and teacher training. This research explores teachers' experiences with the program, highlighting the additional burdens placed on them, such as the personal cost of photocopying materials due to inadequate resources. It also discusses the program's lack of structure, training, and differentiation, as assessed by the Second Congressional Commission on Education (EDCOM 2). The study revealed themes in terms of teacher perspectives prior to the Catch-Up Friday program implementation, namely: educational impact, training and support, awareness and understanding. Moreover, three themes emerged for the challenges such as communication and coordination, teacher workload, and student engagement. Meanwhile, in terms of drawn insights, two themes appeared, namely: the importance of support and idealism and limitations. Furthermore, Theoretical frameworks such as Gardner's Theory of Multiple Intelligences, Organizational Theory, Cultural-Historical Activity Theory (CHAT), Resource Dependency Theory (RDT), and Complexity Theory provide insights into the complexities of implementing educational interventions. By examining these challenges, the study aims to propose solutions to improve the "Catch-Up Fridays" program's effectiveness and support its goal of leaving no student behind.
Assessing the Early Establishment and Adaptability of Italian Ryegrass (Lolium multiflorum) in Irrigated and Rainfed Conditions of Punjab, Pakistan
Authors: Sajjad Zain ul , Zia Faheem , Aslam Muhammad Umar , Shafqat Maleeha , Malook Muhammad Babar , Ali Hassan Rehman , Ahmad Matloob , Inqalabi Talou E Islam
Published: August 2024

In Punjab, Pakistan, more than 60% expenditure incurred on the feeding of livestock and offered low quality forage thus affecting the productivity of milk and meat. The less production of livestock oriented products often results malnutrition in the society. An effort was made to evaluate the Italian Ryegrass (Lolium multiflorum) early growth and its adaptation to rainfed and irrigated environments. The main objective of this study is to provide important new information for sustainable fodder production systems. The experiment used a Randomized Complete Block Design with seeds obtained from Korea and was carried out in the winter of 2023 in both rainfed Chakwal and irrigated Sargodha zone of Punjab. The plant's response to varying soil conditions and water availability was evaluated by measuring a range of growth parameters, such as plant height, population density, root and shoot biomass, root length, and the root-shoot ratio. The results show that there are significant differences between rainfed and irrigated locations as established by the statistical analysis. Italian Ryegrass in irrigated plots showed higher mean plant height (43.75 cm), higher plant population (317.50 plants/m²), higher shoot biomass (7.425 g/plant), greater length of roots (5.950 cm), and a lower root-shoot ratio (0.1135) than in rainfed areas. Additionally, the study provides data on soil profiles that show differences between the two locations in terms of pH, electrical conductivity, nitrogen, phosphorus, and potassium. The findings provide important information for enhancing Italian Ryegrass cultivation in Punjab's various agro-ecological zones, given the critical role fodder feed plays in supporting livestock and agriculture. The study provides the basis for well-informed farming practices by highlighting the importance of water management strategies to improve fodder production during scarcity period and, by consequently, animal nutrition in the area.
Comparative Analysis of Physical and Functional Properties of Colored Horse Gram Varieties (Macrotyloma uniflorum) and Its Flour
Authors: M B Pallavi , N K Uma , S Hemalatha , A G Vijaykumar
Published: August 2024

Pulses has important role in contributing to food and nutritional security and replenishing soil nutrients having a huge potential in addressing needs like future global food security, nutrition and environmental sustainability. Horse gram (Macrotyloma uniflorum) is a minor, under-exploited legume of tropics and subtropics grown under dry-land agriculture. The present study was conducted with the objective to maximize the utilization of horse gram and its flour physical and functional properties. Hundred grain weight and density (3.33 g,1.29 g/ml) were higher in cream colored variety and it was lighter, redder (less green), yellower (less blue) than brown and black colored varieties. Thickness of varieties varied significantly, highest being in brown (2.18 mm) colored variety. Hydration capacity, hydration index, swelling capacity and percent germination (2.92 g/100 grains, 0.93, 3.83 ml/100 grains and 91.66 %) varied significantly with highest being in brown colored variety. Maximum amount of all the flours passed through 52 BSS standard sieve having 300 µ sieve opening. Loose bulk density was high in brown colored flour (0.41 g/ml) whereas tapped bulk density was high in cream colored flour (0.63 g/ml). Cream-colored horse gram flour was lighter (L* value being 78.72), redder (a* value being 5.78) and yellower (b* value being 16.84). There was significant difference in the functional properties of flour. The black colored flour had highest water absorption capacity (2.31 ml/g), oil absorption capacity (2.15 ml/g), swelling power (9.14 g/g), foaming capacity (36.23 %) and foaming stability (32.13 %) than other two flours. The wettability, flowability and cohesiveness of all three flours were good, fair and low respectively. Thus brown and black colored varieties had better physical and functional properties than cream-colored variety. The brown and black colored flour had highest loose bulk density whereas cream colored flour had highest tapped bulk density. Black colored flour had highest water and oil absorption capacity, swelling power, foaming capacity and foaming stability.
Assessment of Genetic Diversity and Identification of Superior Donors for Higher Yield, Nutritional and Processing Traits in Tomato through Hierarchical Clustering Analysis
Authors: Rajak Jitendra , Sharma R. K. , J Jyothsna , Bhardwaj Ajay , Kumar Anand , Sinha Ankit Kumar , Rani Kumari Sweta , Verma Sudhanshu , Kumar Vinay
Published: August 2024

The present investigation was carried out in the Department of Horticulture, BAC, BAU, Sabour, Bihar, with 22 diverse genotypes of tomato germplasms collected from diverse locations and sources. The 22 genotypes were assessed for their phonological, morphological, yield, nutritional and processing quality attributes. The hierarchical clustering analysis based on the Euclidean distance and Ward’s method were applied on these genotypes separately based on two segments namely the morphological and yield attributes; and the nutritional and processing quality attributes, aimed to find superior genotypes from both segments. Further, through the same analysis, the genetic diversity among the 22 genotypes for these traits were also established. Additionally, the association among the plant traits are also partly reported with a heatmap visualization. Our findings suggest that the genotypes 2019/TODVAR-4, 2019/TODVAR-5, 2019/TODVAR-2, 2019/TODVAR-7, and 2019/TOLOCVRES-4 exhibit superior processing quality attributes, compared to the check cultivar Kashi Chayan. In particular, genotypes with higher yields coupled with favorable nutritional and processing qualities significantly enhance the success of breeding programs. Notably, genotype 2019/TODVAR-4 has been identified as particularly suitable for developing cultivars with excellent processing qualities.
Natural Farming: Embracing Regenerative Agriculture for Sustainable Crop Production
Authors: S Nivedha. , Marichamy M. S. , Kanthaswamy V.
Published: August 2024

Natural farming, a regenerative agriculture is advocated and promoted worldwide to produce safe and quality produce and to live in harmony with nature. It is “Chemical free farming” or “do-nothing farming” is a sustainable farming approach that aims to work with nature instead of trying to change it. It focuses on improving soil biological fertility without relying on synthetic chemicals or external inputs. It lies in a simple principle of utilizing low-cost and local inputs with zero utilization of chemicals. Major strategy is continuous application of cow dung and cow urine-based concoctions beside following effective recycling of crop residues, leguminous intercrops as soil cover, pre- monsoon dry sowing, minimizing the irrigation and balancing the soil, air and moisture by irrigating at noon. The farmer is considered only to be a facilitator - the real work is done by Nature herself. No- tillage and farming without the application of herbicides, inorganic fertilizers and pesticides is practiced. Here, actual physical work and labor has been seen to reduce by up to 80% compared to other farming systems. The essence of natural farming is minimizing the external inputs to the farm land, which degenerate the soil nature and improving the crop yield. The Natural farming a cost-effective farming practices with scope for raising employment and rural development. Natural farming also offers a solution to various problems such as food insecurity, farmers distress, health problems arising due to pesticide, fungicide and fertilizers residue in food and water, climate change and natural calamities.
Isolation and Characterization of Azotobacter and Phosphate Solubilizing Bacterial Isolates
Authors: T. S. Koli , R. A. Karande , D. P. Deshmukh , S. J. Waghmare , S. B. Mahajan
Published: August 2024

Isolation from 20 soil samples collected from rhizosphere of watermelon was done on Ashby's medium and Pikovskaya's agar media.8 Azotobacter and 6 Phosphate solubilizing bacteria PSB isolates were obtained from all samples. All the obtained isolates of Azotobacter sp and PSB were gram negative. On morphological study it was observed that, all Azotobacter isolates were motile and positive for KOH test. In case of PSB, the colony shapes of 4 obtained isolates were circular and irregular in 2. All the isolates showed smooth appearance on the media with white colony colour. The biochemical results for both Azotobacter spp and PSB revealed that, most of them were positive for methyl red test, catalase test, starch hydrolysis, gelatine hydrolase test, oxidase test and indol test. Out of eight Azotobacter isolates, Isolate 4 (Azob-1) showed highest (14.25 mg/ml) N fixing ability whereas, from of six PSB isolates, Isolate1 (PSB-1) showed highest solubilising index (4.13) therefore these two isolates were found most efficient in their roles and therefore recommended for use for field experiments.
Mechanical properties and processes of deformation in shallow sedimentary rocks from subduction zones: An experimental study
Authors: Gadenne Leslie , Raimbourg Hugues , Champallier Rémi , Yamamoto Yuzuru
Published: December 2014

To better constrain the mechanical behavior of sediments accreted to accretionary prism, we conducted triaxial mechanical tests on natural samples from the Miura‐Boso paleo‐accretionary prism (Japan) in drained conditions with confining pressures up to 200 MPa as well as postexperiments P‐wave velocity (Vp) measurements. During experiments, deformation is principally noncoaxial and accommodated by two successive modes of deformation, both associated with strain‐hardening and velocity‐strengthening behavior: (1) compaction‐assisted shearing, distributed in a several mm‐wide shear zone and (2) faulting, localized within a few tens of μm‐wide, dilatant fault zone. Deformation is also associated with (1) a decrease in Young's modulus all over the tests, (2) anomalously low Vp in the deformed samples compared to their porosity and (3) an increase in sensitivity of Vp to effective pressure. We interpret this evolution of the poroelastic properties of the material as reflecting the progressive breakage of intergrain cement and the formation of microcracks along with macroscopic deformation. When applied to natural conditions, these results suggest that the deformation style (localized versus distributed) of shallow (z < a few km) sediments is mainly controlled by the variations in stress/strain rate during the seismic cycle and is therefore independent of the porosity of sediments. Finally, we show that the effect of strain, through cement breakage and microcracks formation, may lower Vp for effective pressure up to 40 MPa. As a consequence, the low Vp anomalies observed in Nankai accretionary prisms by seismic imaging between 2 and 4 km depth could reflect sediment deformation rather than porosity anomalies.
Statistical study of magnetic cloud erosion by magnetic reconnection
Authors: Ruffenach A. , Lavraud B. , Farrugia C. J. , Démoulin P. , Dasso S. , Owens M. J. , Sauvaud J.‐A. , Rouillard A. P. , Lynnyk A. , Foullon C. , Savani N. P. , Luhmann J. G. , Galvin A. B.
Published: December 2014

Several recent studies suggest that magnetic reconnection is able to erode substantial amounts of the outer magnetic flux of interplanetary magnetic clouds (MCs) as they propagate in the heliosphere. We quantify and provide a broader context to this process, starting from 263 tabulated interplanetary coronal mass ejections, including MCs, observed over a time period covering 17 years and at a distance of 1 AU from the Sun with Wind (1995–2008) and the two STEREO (2009–2012) spacecraft. Based on several quality factors, including careful determination of the MC boundaries and main magnetic flux rope axes, an analysis of the azimuthal flux imbalance expected from erosion by magnetic reconnection was performed on a subset of 50 MCs. The results suggest that MCs may be eroded at the front or at rear and in similar proportions, with a significant average erosion of about 40% of the total azimuthal magnetic flux. We also searched for in situ signatures of magnetic reconnection causing erosion at the front and rear boundaries of these MCs. Nearly ~30% of the selected MC boundaries show reconnection signatures. Given that observations were acquired only at 1 AU and that MCs are large‐scale structures, this finding is also consistent with the idea that erosion is a common process. Finally, we studied potential correlations between the amount of eroded azimuthal magnetic flux and various parameters such as local magnetic shear, Alfvén speed, and leading and trailing ambient solar wind speeds. However, no significant correlations were found, suggesting that the locally observed parameters at 1 AU are not likely to be representative of the conditions that prevailed during the erosion which occurred during propagation from the Sun to 1 AU. Future heliospheric missions, and in particular Solar Orbiter or Solar Probe Plus, will be fully geared to answer such questions.
Validation of recent shear wave velocity models in the United States with full‐wave simulation
Authors: Gao Haiying , Shen Yang
Published: December 2014

Interpretations of dynamic processes and the thermal and chemical structure of the Earth depend on the accuracy of Earth models. With the growing number of velocity models constructed with different tomographic methods and seismic data sets, there is an increasing need for a systematic way to validate model accuracy and resolution. This study selects five shear wave velocity models in the U.S. and simulates full‐wave propagation within the 3‐D structures. Surface‐wave signals extracted from ambient seismic noise and regional earthquakes are compared with synthetic waveforms at multiple‐frequency bands. Phase delays and cross‐correlation coefficients between observed and synthetic waveforms allow us to compare and validate these models quantitatively. In general, measurements from regional earthquakes are consistent with ambient noise results, but appear more scattered, which may result from uncertainty of the earthquake source location, origin time, and moment tensor. Our results show the improvement of model prediction with the increase of seismic data sets and implement of advanced methods. There exists a positive linear trend between phase delay and interstation distance for three models, indicating that on average, these models are faster than the real Earth structure. The phase delays from the jointly inverted model of ambient noise and receiver function have negative means at all periods while without obvious dependence on the interstation distance. The full‐wave ambient noise tomographic model predicts more accurate phase arrivals compared to other models. This study suggests a need for an integrated model constructed with multiple seismic waveforms and consideration of anisotropy and attenuation.
Penultimate predecessors of the 2004 Indian Ocean tsunami in Aceh, Sumatra: Stratigraphic, archeological, and historical evidence
Authors: Sieh Kerry , Daly Patrick , Edwards McKinnon E. , Pilarczyk Jessica E. , Chiang Hong‐Wei , Horton Benjamin , Rubin Charles M. , Shen Chuan‐Chou , Ismail Nazli , Vane Christopher H. , Feener R. Michael
Published: December 2014

We present stratigraphic, archeological and historical evidence for two closely timed predecessors of the giant 2004 tsunami on the northern coast of Aceh, northern Sumatra. This is the first direct evidence that a tsunami played a role in a fifteenth century cultural hiatus along the northern Sumatran portion of the maritime silk route. One seacliff exposure on the eastern side of the Lambaro headlands reveals two beds of tsunamigenic coral rubble within a small alluvial fan. Radiocarbon and Uranium‐Thorium disequilibrium dates indicate emplacement of the coral rubble after 1344 ± 3 C.E. Another seacliff exposure, on the western side of the peninsula, contains evidence of nearly continuous settlement from ~1240 C.E. to soon after 1366 ± 3 C.E., terminated by tsunami destruction. At both sites, the tsunamis are likely coincident with sudden uplift of coral reefs above the Sunda megathrust 1394 ± 2 C.E., evidence for which has been published previously. The tsunami (or tsunami pair) appears to have destroyed a vibrant port community and led to the temporary recentering of marine trade dominance to more protected locations farther east. The reestablishment of vibrant communities along the devastated coast by about 1500 CE set the stage for the 2004 disaster.
Strain rate‐dependent lithosphere rifting and necking architectures in analog experiments
Authors: Nestola Yago , Storti Fabrizio , Cavozzi Cristian
Published: December 2014

Analog models provide a useful tool to investigate on the three‐dimensional evolution of geodynamic processes. In this contribution, we describe the results of an experimental program designed for studying the progression through time of lithosphere thinning and necking. In particular, by exploiting the three‐dimensional real‐time information on surface topography and base lithosphere geometry provided by paired top and bottom laser scanning, we studied the evolution of lithosphere necking at low and fast asymmetric plate divergence. Our results indicate that this parameter plays a fundamental control on the incremental and finite slope of the lithosphere necking. Influences are discussed on the application of experimental data to natural rift system.
Simulating diurnal variations over the southeastern United States
Authors: Selman Christopher , Misra Vasubandhu
Published: December 2014

The diurnal variations from a high‐resolution regional climate model (Regional Spectral Model; RSM) are analyzed from six independent decade long integrations using lateral boundary forcing data from the National Centers for Environmental Prediction Reanalysis 2 (NCEPR2), European Center for Medium‐Range Weather Forecasts 40‐year Reanalysis and the Twentieth Century Reanalysis (20CR). With each of these lateral boundary forcing data, the RSM is integrated separately using two convection schemes: Relaxed Arakawa‐Schubert and Kain‐Fritsch. The results show that RSM integrations forced with 20CR have the least fidelity in depicting the seasonal cycle and diurnal variability of precipitation and surface temperature over the Southeastern United States. The remaining four model simulations show comparable skill. The differences in the diurnal amplitude of rainfall during the summer months of the 20CR forced integration from the corresponding NCEPR2 forced integration, for example, is found to be largely from the transient component of the moisture flux convergence. The root mean square error (RMSE) of the seasonal cycle of precipitation and surface temperature of the other four simulations (not forced by 20CR) were comparable to each other and highest in the summer months. But the RMSE of the diurnal amplitude of precipitation and the timing of its diurnal zenith were largest during winter months and least during summer and fall months in the four model simulations (not forced by 20CR). The diurnal amplitude of surface temperature in comparison showed far less fidelity in all models. The phase of the diurnal maximum of surface temperature however showed significantly better validation with corresponding observations in all of the six model simulations.
Modeled responses of summer climate to realistic land use/cover changes from the 1980s to the 2000s over eastern China
Authors: Hu Yang , Zhang Xue‐Zhen , Mao Rui , Gong Dao‐Yi , Liu Hong‐bo , Yang Jing
Published: December 2014

Eastern China has experienced substantial agricultural expansion and deforestation in recent decades. We modeled the influence of land use/cover changes (LUCCs) over eastern China on the regional climate using the Weather Research and Forecasting model with the Noah‐multiparameterization land surface scheme. Two 21 year (1980–2000) experiments were performed using the same settings, except for the land use/cover data for the 1980s and the 2000s. The results showed that in northern China, decreases in the surface air temperature of approximately 0.3–0.5°C and decreases (increases) in rainfall over the lower reaches of the Yangtze River valley (southern China, northeastern China, and the Korean Peninsula) of approximately 3% (6–7%) in the summer were associated with LUCCs in eastern China from the 1980s to the 2000s. The cooling effect in northern China, which was primarily attributable to an increase in the surface latent heat flux of approximately 7.3–9.6 W m−2, weakened the land‐ocean thermal contrast, suggesting the presence of a weaker summer monsoon over eastern China. As a result, rainfall over the lower reaches of the Yangtze River valley (southern China) tended to decrease (increase). In addition, the cooling effect may have produced an anomalous cyclonic circulation from the surface to the midtroposphere over northeastern China and the Korean Peninsula, resulting in increased rainfall over this area.
Multiscale geophysical imaging of the critical zone
Authors: Parsekian A. D. , Singha K. , Minsley B. J. , Holbrook W. S. , Slater L.
Published: December 2014

Details of Earth's shallow subsurface—a key component of the critical zone (CZ)—are largely obscured because making direct observations with sufficient density to capture natural characteristic spatial variability in physical properties is difficult. Yet this inaccessible region of the CZ is fundamental to processes that support ecosystems, society, and the environment. Geophysical methods provide a means for remotely examining CZ form and function over length scales that span centimeters to kilometers. Here we present a review highlighting the application of geophysical methods to CZ science research questions. In particular, we consider the application of geophysical methods to map the geometry of structural features such as regolith thickness, lithological boundaries, permafrost extent, snow thickness, or shallow root zones. Combined with knowledge of structure, we discuss how geophysical observations are used to understand CZ processes. Fluxes between snow, surface water, and groundwater affect weathering, groundwater resources, and chemical and nutrient exports to rivers. The exchange of gas between soil and the atmosphere have been studied using geophysical methods in wetland areas. Indirect geophysical methods are a natural and necessary complement to direct observations obtained by drilling or field mapping. Direct measurements should be used to calibrate geophysical estimates, which can then be used to extrapolate interpretations over larger areas or to monitor changing processes over time. Advances in geophysical instrumentation and computational approaches for integrating different types of data have great potential to fill gaps in our understanding of the shallow subsurface portion of the CZ and should be integrated where possible in future CZ research.
Understanding instrumental Stokes leakage in Murchison Widefield Array polarimetry
Authors: Sutinjo A. , O'Sullivan J. , Lenc E. , Wayth R. B. , Padhi S. , Hall P. , Tingay S. J.
Published: December 2014

This paper offers an electromagnetic, more specifically array theory, perspective on understanding strong instrumental polarization effects for planar low‐frequency “aperture arrays” with the Murchison Widefield Array (MWA) as an example. A long‐standing issue that has been seen here is significant instrumental Stokes leakage after calibration, particularly in Stokes Q at high frequencies. A simple model that accounts for interelement mutual coupling is presented which explains the prominence of Q leakage seen when the array is scanned away from zenith in the principal planes. On these planes, the model predicts current imbalance in the X (E‐W) and Y (N‐S) dipoles and hence the Q leakage. Although helpful in concept, we find that this model is inadequate to explain the full details of the observation data. This finding motivates further experimentation with more rigorous models that account for both mutual coupling and embedded element patterns. Two more rigorous models are discussed: the “full” and “average” embedded element patterns. The viability of the full model is demonstrated by simulating current MWA practice of using a Hertzian dipole model as a Jones matrix estimate. We find that these results replicate the observed Q leakage to approximately 2 to 5%. Finally, we offer more direct indication for the level of improvement expected from upgrading the Jones matrix estimate with more rigorous models. Using the average embedded pattern as an estimate for the full model, we find that Q leakage of a few percent is achievable.
Anomalous absorption, plasmonic resonances, and invisibility of radially anisotropic spheres
Authors: Wallén Henrik , Kettunen Henrik , Sihvola Ari
Published: December 2014

This article analyzes the response of a sphere with radially anisotropic permittivity dyadic (RA sphere), in both the electrostatic and full electrodynamic settings. Depending on the values and signs of the permittivity components, the quasistatic polarizability of the RA sphere exhibits several very different interesting properties, including invisibility, field concentration, resonant singularities, and emergent losses. Special attention is given to the anomalous losses that appear in the case of certain hyperbolic anisotropy values. We show that their validity can be justified in a limiting sense by puncturing the sphere at the origin and adding a small imaginary part into the permittivity components. A hyperbolic RA sphere with very small intrinsic losses can thus have significant effective losses making it an effective absorber. With different choices of permittivities, the RA sphere could also perform as a cloak or a sensor. The Mie scattering results by an RA sphere are used to justify the quasistatic calculations. It is shown that in the small parameter limit the absorption efficiency of an RA sphere is nonzero for certain lossless hyperbolic anisotropies. The absorption and scattering efficiencies agree with the quasistatic calculations fairly well for spheres with size parameters up to 1/3.
Extremely low frequency band station for natural electromagnetic noise measurement
Authors: Fornieles‐Callejón J. , Salinas A. , Toledo‐Redondo S. , Portí J. , Méndez A. , Navarro E. A. , Morente‐Molinera J. A. , Soto‐Aranaz C. , Ortega‐Cayuela J. S.
Published: December 2014

A new permanent ELF measurement station has been deployed in Sierra Nevada, Spain. It is composed of two magnetometers, oriented NS and EW, respectively. At 10 Hz, their sensitivity is 19 μV/pT and the signal‐to‐noise ratio (SNR) is 28 dB for a time‐varying signal of 1 pT, the expected field amplitude in Sierra Nevada. The station operates for frequencies below 24 Hz. The magnetometers, together with their corresponding electronics, have been specifically designed to achieve such an SNR for small signals. They are based on high‐resolution search coils with ferromagnetic core and 106 turns, operating in limited geometry configuration. Different system noise sources are considered, and a study of the SNR is also included. Finally, some initial Schumann resonance measurements are presented in order to validate the performance of the measurement station, including 1 h length spectra, daily variations of resonance amplitudes and frequencies for the different seasons, and a 3 day spectrogram.
Effective Photothermal Killing of Pathogenic Bacteria by Using Spatially Tunable Colloidal Gels with Nano‐Localized Heating Sources
Authors: Hsiao Chun‐Wen , Chen Hsin‐Lung , Liao Zi‐Xian , Sureshbabu Radhakrishnan , Hsiao Hsu‐Chan , Lin Shu‐Jyuan , Chang Yen , Sung Hsing‐Wen
Published: December 2014

Alternative approaches to treating subcutaneous abscesses—especially those associated with antibiotic‐resistant pathogenic bacterial strains—that eliminate the need for antibiotics are urgently needed. This work descibes a chitosan (CS) derivative with self‐doped polyaniline (PANI) side chains that can self‐assemble into micelles in an aqueous environment and be transformed into colloidal gels in a process that is driven by a local increase in pH. These self‐doped PANI micelles can be utilized as nano‐localized heat sources, remotely controllable using near‐infrared (NIR) light. To test the in vivo efficacy of the CS derivative as a photothermal agent, an aqueous solution thereof is directly injected at the site of infected abscesses in a mouse model. The injected polymer solution eventually becomes distributed over the acidic abscesses, forming colloidal gels when it meets the boundaries of healthy tissues. After treatment with an 808 nm laser, the colloidal gels convert NIR light into heat, causing the thermal lysis of bacteria and repairing the infected wound without leaving residual implanted materials. This approach has marked potential because it can provide colloidal gels with tunable spatial stability, limiting localized heating to the infected sites, and reducing thermal damage to the surrounding healthy tissues.
Hydrophobically modified poly(vinyl alcohol) and bentonite nanocomposites thereof: Barrier, mechanical, and aesthetic properties
Authors: Johansson Caisa , Clegg Francis
Published: December 2014

Composite films were formed by incorporating three different bentonites into an ethylene modified, water‐soluble poly(vinyl alcohol), EPVOH. The interaction of EPVOH with both hydrophilic and hydrophobic bentonites was investigated. EPVOH provided lower water vapor and oxygen transmission rates compared to a conventional PVOH grade when exposed at high relative humidities (70–90% RH). EPVOH films which exhibited oxygen barrier properties comparable to that of a biaxially oriented PET packaging film at 80% RH were produced. High compatibility between EPVOH and hydrophilic bentonites provided an even distribution of clay platelets in the composites. A strong increase in Young's modulus with increased addition of any of the three bentonites was found. At low addition levels the hydrophobic bentonite proved to be effective in terms of maintaining high elongation at break, high transparency and high gloss. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41737.
Preparation, characterization, and flocculation performance ofP(acrylamide‐co‐diallyldimethylammonium chloride) by UV‐initiated template polymerization
Authors: Guan Qingqing , Zheng Huaili , Zhai Jun , Liu Bingzhi , Sun Yongjun , Wang Yili , Xu Zhinan , Zhao Chun
Published: December 2014

This study prepared TPDA, a high‐intrinsic‐viscosity cationic polyacrylamide, through ultraviolet (UV)‐initiated template polymerization. Acrylamide (AM) and diallyldimethylammonium chloride (DMD) served as monomers, and poly sodium polyacrylate (PAAS) served as the template. The structure of TPDA was characterized by Fourier‐transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The synthetic conditions of TPDA were studied and optimized by single‐factor experiments. An optimized product was obtained at an intrinsic viscosity of 11.3 dL g−1and a conversion rate of 97.2% with a total monomer concentration of 20%, DMD concentration of 30%, initiator concentration of 0.045%, pH of 8, EDTA concentration of 0.3%, and UV irradiation of 90 min. Results showed that TPDA was the copolymer of AM and DMD with a micro‐block structure at the molecular chain. Given its high intrinsic viscosity and cationic block structure, TPDA performed better in kaolin flocculation than that prepared without template addition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41747.
Plasticization effects of dihydroxyl soybean oil improve flexibilities of epoxy‐based films for coating applications
Authors: Sung Jonggeun , Li Yonghui , Sun Xiuzhi Susan
Published: December 2014

Novel bio‐based coating materials were developed through cationic ring‐opening photopolymerization of dihydroxyl soybean oil (DSO) with commercial epoxy monomers [i.e., epoxidized soybean oil (ESO) and 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexanecarboxylate (ECHM). The ether cross‐linking and post‐polymerization of the polymeric network were observed using Fourier transform infrared spectroscopy. Thermal properties of the bio‐based coating materials and their copolymerization behaviors were examined using differential scanning calorimetry and a thermogravimetric analyzer. Cross‐link density and molecular weight between cross‐link were obtained from dynamic mechanical analysis. ECHM/DSO (1 : 1.43 weight ratio) films showed the highest elongation at break (49.2%) with a tensile strength of 13.7 MPa. After 2 months of storage, the elongation at break and tensile strength of films were 32% and 15.1 MPa, respectively. ESO/DSO films (w/w ratios of 1 : 0.1, 1 : 0.15, and 1 : 0.2) exhibited stable flexibility of 11–13% of elongation at break without significant reductions in tensile strength (2.5–4.4 MPa) during a 2‐month shelf life. Optical transparencies of the films were comparable to commercial glass and polymers, and water uptake properties (0.72% and 2.83%) were significantly low. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41773.
A surface‐renewal model for constant flux cross‐flow microfiltration
Authors: Jiang Shaopeng , Chatterjee Siddharth G.
Published: December 2014

A mathematical model using classical cake‐filtration theory and the surface‐renewal concept is formulated for describing constant flux, cross‐flow microfiltration (CFMF). The model provides explicit analytical expressions for the transmembrane pressure drop (TMP) and cake‐mass buildup on the membrane surface as a function of filtration time. The basic parameters of the model are the membrane resistance, specific cake resistance, and rate of surface renewal. The surface‐renewal model has two forms: the complete model, which accounts for cake compressibility; and a subsidiary model for incompressible cakes, which can be derived from the complete model. The subsidiary model is correlated against some of the experimental TMP data reported by Miller et al. (J Membrane Sci 2014, 452, 171) for constant flux CFMF of a soybean‐oil emulsion in a cross‐flow filtration cell having unmodified and surface‐modified, fouling‐resistant membranes, and has an average root‐mean‐square (RMS) error of 6.2%. The complete model is fitted to the experimental TMP data reported by Ho and Zydney (J Membrane Sci, 2002, 209, 363) for constant flux microfiltration of a bovine serum albumin solution in a stirred cell using polycarbonate track‐etched membranes and has an average RMS error of 11.5%. This model is also correlated against the TMP data of Kovalsky et al. (J Membrane Sci 2009, 344, 204) for constant flux yeast filtration in a stirred cell (average RMS error = 9.2%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41778.
Ternary polymer blends based on poly(lactic acid): Effect of stereo‐regularity and molecular weight
Authors: Ross Sukunya , Mahasaranon Sararat , Ross Gareth M.
Published: December 2014

The effects of stereo‐regularity and molecular weight of poly(lactic acid) (PLA) on ternary polymer blends was analyzed using optical clarity as the primary screening method. This enabled the ready identification of phase boundaries of optically clear and apparently miscible regions. Solvent‐mediated blends of amorphous poly(dl‐lactide) (PDLLA) and semi‐crystalline poly(l‐lactide) (PLLA) with various molecular weights from high to low, along with polycaprolactone (PCL) and cellulose acetate butyrate (CAB) were used in this study. The nature and extent of crystallinity of the blends was examined by X‐ray diffraction, which, in conjunction with differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy, provided information about the competition between polymer crystallization (self‐aggregating behavior) and intermixing of the macromolecules. Thus, allowing the primary physical cause of transparency loss to be identified. The results of the ternary blends optical clarity showed the position of the phase boundaries in PLLA/PCL/CAB and PDLLA/PCL/CAB blends are significantly affected by the stereo‐regularity and molecular weight of PLA. The PDLLA (amorphous) blend shows comparable regions of phase separation with high molecular weight and semi‐crystalline PLLA blends even though the molecular weight is much lower. The blends of the shorter chain PLLA1 tend to show more crystalline regions. The optical transparency, miscibility, and crystallinity of the blends are not only affected by the stereo‐regularity and molecular weight of PLA but also the crystallizable PCL, especially at high loading. These findings give useful information to the film‐packaging sector where good optical clarity is a critical performance requirement. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41780.
The effect of controlled degradation on the molecular characteristics of heterophasic ethylene–propylene copolymers
Authors: Swart Morne , Van Reenen Albert J.
Published: December 2014

A commercial heterophasic ethylene–propylene copolymer (HEPC) produced by Sasol Polymers using a Ziegler‐Natta catalysed gas‐phase process was vis‐broken (controlled degradation) to various degrees by making use of an organic peroxide. The effects of the amount of vis‐breaking on the molecular characteristics and physical properties were subsequently studied by making use of preparative Temperature Rising Elution Fractionation (p‐TREF), Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC), High Temperature Size Exclusion Chromatography (HT‐SEC), and deposition of the SEC fractions via the LC Transform Interface (SEC‐FTIR). It was found that by increasing the amount of organic peroxide, the molecular characteristics of the heterophasic copolymer are severely affected and hence influence the physical characteristics of the polymer dramatically. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41783.
Nanomechanical properties and thermal stability of recycled cellulose reinforced starch–gelatin polymer composite
Authors: Rodríguez‐Castellanos Wendy , Flores‐Ruiz Francisco Javier , Martínez‐Bustos Fernando , Chiñas‐Castillo Fernando , Espinoza‐Beltrán Francisco Javier
Published: December 2014

Samples of starch−gelatin polymer reinforced with 5% of recycled cellulose were prepared using an extrusion‐compression molding process. Nanoindentation and atomic force acoustic microscopy (AFAM) techniques were used to study the effect of reinforcement at nanoscale level. Nanoindentation tests show a 163% increase in hardness and 123% of elastic modulus enhancement after recycled cellulose inclusion. AFAM shows that distribution of recycled cellulose into the polymer matrix is rather homogeneous at nanoscale which improves load transfer. Thermogravimetric analysis indicates an increase in thermal stability of the cellulose reinforced polymer matrix samples. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41787.
Pathways between soil moisture and precipitation in southeastern South America
Authors: Ruscica Romina C. , Sörensson Anna A. , Menéndez Claudio G.
Published: December 2014

Southeastern South America (SESA) is found to be the main hot spot of soil moisture–evapotranspiration coupling of South America during a dry summer. However, only its eastern part is a soil moisture–precipitation hot spot. Pathways between soil moisture and precipitation are evaluated through studying the coupling of soil moisture with surface and boundary layer variables. The outcome suggests that both the moist static energy and its vertical gradient are important for the development of precipitation, as a result of the total surface heat fluxes that are affected by soil moisture only in the eastern part of SESA.