bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Postharvest Quality of Fresh Kesum Leaves (Persicaria minor) during Storage in Different Temperatures and Packaging
Authors: M. N. Mohd Effendi , M. Razali , T. Muhammad Faidhi , M. Y. Saidatul Aqilah 
Published: September 2024

Persicaria minor, locally known as kesum, is an herb synonym in Southeast Asia as a food flavor enhancer and seasoning for Eastern delicacies. Kesum leaves are quickly wilted, shrink, and lose moisture once harvested. This study aimed to determine optimum parameters: storage temperature and suitable packaging to maintain the freshness and quality of kesum and prolong the storage life. This study consisted of two activities: determining the best storage temperature and determining suitable packaging. For the first activity, kesum leaves were harvested manually from matured plants, transported to a packinghouse, sorted, cleaned, packed, and sealed in polyethylene (PE) 0.04mm before being stored at different temperatures, which were 5°C, 8°C, 10°C and 13°C, while for the second activity, kesum leaves were packed and sealed in different packaging: polyethylene (PE) 0.04mm and polypropylene (PP) 0.04mm and stored at 5°C. The postharvest quality of all samples and treatments (weight, moisture content, pH, total titratable acidity, total soluble solids, respiration rate of the leaves, total phenolic content, and leaf color values) was measured and recorded weekly throughout the storage period. The study's results found that storing fresh kesum leaves at 5°C temperature and in PE 0.04mm packaging can delay the senescence and maintain the quality and postharvest attributes for up to 35 days, as shown in lower respiration rate, maintain the pH, total titratable acidity, total soluble solids and color of the leaves, and show higher total phenolic content for up to 35 days of storage compared to storing in temperature of 8°C, 10°C, and 13°C and PP 0.04mm packaging.
Rosetta measurements of lower hybrid frequency range electric field oscillations in the plasma environment of comet 67P
Authors: Karlsson T. , Eriksson A. I. , Odelstad E. , André M. , Dickeli G. , Kullen A. , Lindqvist P.‐A. , Nilsson H. , Richter I. 
Published: February 2017

AbstractElectric field measurements from cometary environments are very rare but can provide important information on how plasma waves help fashion the plasma environment. The long dwelling time of the Rosetta spacecraft close to comet 67P/Churyumov‐Gerasimenko promises to improve this state. We here present the first electric field measurements from 67P, performed by the Rosetta dual Langmuir probe instrument LAP. Measurements of the electric field from cometocentric distances of 149 and 348 km are presented together with estimates of plasma density changes. Persistent wave activity around the local H2O+ lower hybrid frequency is observed, with the largest amplitudes observed at sharp plasma gradients. We demonstrate that the necessary requirements for the lower hybrid drift instability to be operating are fulfilled. We suggest that lower hybrid waves are responsible for the creation of a warm electron population, the origins of which have been unknown so far, by heating ambient electrons in the magnetic field‐parallel direction.
Role of IMF By in the prompt electric field disturbances over equatorial ionosphere during a space weather event
Authors: Chakrabarty D. , Hui Debrup , Rout Diptiranjan , Sekar R. , Bhattacharyya Archana , Reeves G. D. , Ruohoniemi J. M. 
Published: February 2017

AbstractOn 7 January 2005 (Ap=40) prompt penetration electric field perturbations of opposite polarities were observed over Thumba and Jicamarca on a few occasions during 13:45–16:30 UT. However, the electric field was found to be eastward during 14:45–15:30 UT over both Thumba and Jicamarca contrary to the general expectation wherein opposite polarities are expected at nearly antipodal points. On closer scrutiny, three important observational features are noticed during 14:10–15:15 UT. First, during 14:10–14:45 UT, despite increasing southward interplanetary magnetic field (IMF) Bz condition, the already westward electric field over Thumba weakened (less westward) while the eastward electric field over Jicamarca intensified (more eastward). Second, the electric field not only became anomalously eastward over Thumba but also got intensified further during 14:45–15:00 UT similar to Jicamarca. Third, during 15:00–15:15 UT, despite IMF Bz remaining steadily southward, the eastward electric field continued to intensify over Thumba but weakened over Jicamarca. It is suggested that the changes in IMF By component under southward IMF Bz condition are responsible for skewing the ionospheric equipotential patterns over the dip equator in such a way that Thumba came into the same DP2 cell as that of Jicamarca leading to anomalous electric field variations. Magnetic field measurements along the Indian and Jicamarca longitude sectors and changes in high‐latitude ionospheric convection patterns provide credence to this proposition. Thus, the present investigation shows that the variations in IMF By are fundamentally important to understand the prompt penetration effects over low latitudes.
Saturn's magnetic field periodicities at high latitudes and the effects of spacecraft motion and position
Authors: Carbary J. F. , Provan G. 
Published: February 2017

AbstractLomb periodogram analyses have been applied to magnetic field observations made by the Cassini spacecraft during its high‐latitude orbits from 2006 to 2009. Only data from open‐field regions (OFRs), identified by absence of thermal electrons, were used to separate pure north and south periodic signals. In agreement with previous investigations, the periodograms reveal signals at 10.6 h in the northern OFR and at 10.8 h in the southern OFR but only for the Bθ and Bϕ components. The Br component exhibited essentially no periodicity in either the north or south, or at least its periodicity amplitude was too small for detection. In addition, the Bθ and Bϕ components displayed signals at ~10.0 h and ~11.2 h in the north and ~10.2 h and ~11.5 h and possibly ~9.6 h in the south. These periods can be reproduced by a simulation by using a rotating “searchlight” model with different north and south periods and an r−3 dependence. This investigation employs a Lomb‐Scargle method to analyze magnetic field periodicities and confirms that the magnetic fields have “pure” north and south periods in the respective hemispheres. The results also imply that a radial dependence in these fields exists, which is expected if the fields are produced by field‐aligned currents. Using this model, the effects of spacecraft motion and position can be readily detected in the Lomb analyses.
Constraints on Io's interior from auroral spot oscillations
Authors: Roth Lorenz , Saur Joachim , Retherford Kurt D. , Blöcker Aljona , Strobel Darrell F. , Feldman Paul D. 
Published: February 2017

AbstractThe morphology of Io's aurora is dominated by bright spots near the equator that oscillate up and down in approximate correlation with the oscillating orientation of the Jovian magnetospheric field. Analyzing Hubble Space Telescope images, we find that the auroral spots oscillate in phase with the time‐variable Jovian magnetic field at Io and that the amplitude of the spot oscillations is reduced by 15% (±5%) with respect to the amplitude of the magnetic field oscillation. We investigate the effects of Io's plasma interaction and magnetic induction in the moon's interior on the magnetic field topology and the aurora oscillations using a magnetohydrodynamic (MHD) simulation and an analytical induction model. The results from the MHD simulation suggest that the plasma interaction has minor effects on the oscillations, while the magnetic induction generally reduces magnetic field oscillations near the surface. However, the analytical model shows that induction in any near‐surface layer for which the skin depth is larger than the thickness—like a conductive magma ocean—would induce a phase shift, in conflict with the observations. Under the assumption that the spot oscillations represent the magnetic field oscillation, we constrain the conductance of a near‐surface layer to 1 × 103 S or lower. A magma ocean with conductances of 104 S or higher as derived from Galileo magnetometer measurements would cause overly strong attenuation of the amplitude in addition to the irreconcilable phase shift. The observed weakly attenuated, in‐phase spot oscillation is consistent with induction in a deep, highly conductive layer like Io's metallic core.
Contrasting Mesozoic evolution across the boundary between on and off craton regions of the South African plateau inferred from apatite fission track and (U‐Th‐Sm)/He thermochronology
Authors: Wildman Mark , Brown Roderick , Persano Cristina , Beucher Romain , Stuart Finlay M. , Mackintosh Vhairi , Gallagher Kerry , Schwanethal James , Carter Andrew 
Published: February 2017

AbstractThe timing and mechanisms involved in creating the elevated, low‐relief topography of the South African plateau remain unresolved. Here we constrain the thermal history of the Southwest African plateau since 300 Ma by using apatite fission track (AFT) and (U‐Th‐Sm)/He (AHe) thermochronology. Archean rocks from the center of the Kaapvaal Craton yield AFT ages of 331.0 ± 11.0 and 379.0 ± 23.0 Ma and mean track lengths (MTLs) of 11.9 ± 0.2 and 12.5 ± 0.3 µm. Toward the southwest margin of the craton and in the adjacent Paleozoic mobile belt, AFT ages are significantly younger and range from 58.9 ± 5.9 to 128.7 ± 6.3 Ma and have longer MTLs (>13 µm). The range of sample AHe ages complements the AFT ages, and single‐grain AHe ages for most samples are highly dispersed. Results from joint inverse modeling of these data reveal that the center of the craton has resided at near‐surface temperatures (<60°C) since 300 Ma, whereas the margins of the craton and the off‐craton mobile belt experienced two discrete episodes of cooling during the Cretaceous. An Early Cretaceous cooling episode is ascribed to regional denudation following continental breakup. Late Cretaceous cooling occurs regionally but is locally variable and may be a result of a complex interaction between mantle‐driven uplift and the tectonic setting of the craton margin. Across the entire plateau, samples are predicted to have remained at near‐surface temperatures throughout the Cenozoic, suggesting minimal denudation (<1 km) and relative tectonic stability of the plateau.
Variability of the Pacific North Equatorial Current from 1993 to 2012 based on a 1/8° Pacific model simulation
Authors: Zhang Zhichun , Xue Huijie , Chai Fei , Chao Yi 
Published: February 2017

AbstractBased on a multidecadal Pacific basin model simulation, interannual variations of the North Equatorial Current (NEC) are investigated. The model reproduces well the characteristics of the NEC and its interannual variability. The NEC transport is calculated as an integral of the westward velocity from 6°N to 21°N and from the surface to the 1200 m depth. The magnitude and standard deviation of the NEC transport increase from 46.5 and 3.9 Sv at 175°E to 66.7 and 6.5 Sv at 130°E, respectively, and both peak around 132°E prior to entering the bifurcation region. The NEC transport tends to be higher during positive Oceanic Niño Index (ONI) years but lower during negative ONI years with the maximum difference of more than 20 Sv. The interannual variability of the NEC transport is closely related to changes of the sea surface height in the tropical Pacific Ocean, and the increase of the NEC is mostly balanced by the increase in the North Equatorial Counter Current (NECC) on the tropical gyre side. The present study further suggests a long‐term decline of the NEC transport from 1993 to 2012, which is consistent with the patterns in the trend of wind stress curl. Transport anomalies reconstructed from the normal modes of zonal velocity suggest that the first baroclinic mode captures about 95% of the variance in the NEC transport, while the second mode adds only additional 3–4%. A 1.5‐layer reduced gravity model further reveals that the first (second) baroclinic mode is driven primarily by the wind (thermal) forcing. The wind forcing plays a predominant role in determining the interannual variability in the NEC transport while the effect of the thermal forcing is rather limited.
The coastal streamflow flux in the Regional Arctic System Model
Authors: Hamman Joseph , Nijssen Bart , Roberts Andrew , Craig Anthony , Maslowski Wieslaw , Osinski Robert 
Published: February 2017

AbstractThe coastal streamflow flux from the Arctic drainage basin is an important driver of dynamics in the coupled ice‐ocean system. Comprising more than one third of the total freshwater flux into the Arctic Ocean, streamflow is a key component of the regional and global freshwater cycle. To better represent the coupling of the streamflow flux to the ocean, we have developed and applied the RVIC streamflow routing model within the Regional Arctic System Model (RASM). The RASM is a high‐resolution regional Earth System Model whose domain includes all of the Arctic drainage basin. In this paper, we introduce the RVIC streamflow routing model, detailing its application within RASM and its advancements in terms of representing high‐resolution streamflow processes. We evaluate model simulated streamflow relative to in situ observations and demonstrate a method for improving model performance using a simple optimization procedure. We also present a new, spatially and temporally consistent, high‐resolution data set of coastal freshwater fluxes for the Arctic drainage basin and surrounding areas that is based on a fully coupled RASM simulation and intended for use in Arctic Ocean modeling applications. This data set is evaluated relative to other coastal streamflow data sets commonly used by the ocean modeling community. We demonstrate that the RASM‐simulated streamflow flux better represents the annual cycle than existing data sets, especially in ungauged areas. Finally, we assess the impact that streamflow has on the coupled ice‐ocean system, finding that the presence of streamflow leads to reduced sea surface salinity, increased sea surface temperatures, and decreased sea ice thickness.
Snow contribution to first‐year and second‐year Arctic sea ice mass balance north of Svalbard
Authors: Granskog Mats A. , Rösel Anja , Dodd Paul A. , Divine Dmitry , Gerland Sebastian , Martma Tõnu , Leng Melanie J. 
Published: February 2017

AbstractThe salinity and water oxygen isotope composition (δ18O) of 29 first‐year (FYI) and second‐year (SYI) Arctic sea ice cores (total length 32.0 m) from the drifting ice pack north of Svalbard were examined to quantify the contribution of snow to sea ice mass. Five cores (total length 6.4 m) were analyzed for their structural composition, showing variable contribution of 10–30% by granular ice. In these cores, snow had been entrained in 6–28% of the total ice thickness. We found evidence of snow contribution in about three quarters of the sea ice cores, when surface granular layers had very low δ18O values. Snow contributed 7.5–9.7% to sea ice mass balance on average (including also cores with no snow) based on δ18O mass balance calculations. In SYI cores, snow fraction by mass (12.7–16.3%) was much higher than in FYI cores (3.3–4.4%), while the bulk salinity of FYI (4.9) was distinctively higher than for SYI (2.7). We conclude that oxygen isotopes and salinity profiles can give information on the age of the ice and enables distinction between FYI and SYI (or older) ice in the area north of Svalbard.
Spatial variability of active layer thickness detected by ground‐penetrating radar in the Qilian Mountains, Western China
Authors: Cao Bin , Gruber Stephan , Zhang Tingjun , Li Lili , Peng Xiaoqing , Wang Kang , Zheng Lei , Shao Wanwan , Guo Hong 
Published: February 2017

AbstractThe active layer plays a key role in geomorphic, hydrologic, and biogeochemical processes in permafrost regions. We conducted a systematic investigation of active layer thickness (ALT) in northeastern Qinghai‐Tibetan Plateau by using ground‐penetrating radar (GPR) with 100 and 200 MHz antennas. We used mechanical probing, pit, and soil temperature profiles for evaluating ALT derived from GPR. The results showed that GPR is competent for detecting ALT, and the error was ±0.08 m at common midpoint co‐located sites. Considerable spatial variability of ALT owing to variation in elevation, peat thickness, and slope aspect was found. The mean ALT was 1.32 ± 0.29 m with a range from 0.81 to 2.1 m in Eboling Mountain. In Yeniu Gou, mean ALT was 2.72 ± 0.88 m and varied from 1.07 m on the north‐facing slope to 4.86 m around the area near the lower boundary of permafrost. ALT in peat decreased with increasing elevation at rates of −1.31 m/km (Eboling Mountain) and −2.1 m/km (Yeniu Gou), and in mineral soil in Yeniu Gou, the rate changed to −4.18 m/km. At the same elevation, ALT on the south‐facing slope was about 0.8 m thicker than that on the north‐facing slopes, while the difference was only 0.18 m in peat‐covered area. Within a 100 m2 area with a local elevation difference of 0.8 m, ALT varied from 0.68 m to 1.25 m. Both field monitoring and modeling studies on spatial ALT variations require rethinking of the current strategy and comprehensive design.
Quantifying uncertainties from additional nitrogen data and processes in a terrestrial ecosystem model with Bayesian probabilistic inversion
Authors: Du Zhenggang , Zhou Xuhui , Shao Junjiong , Yu Guirui , Wang Huimin , Zhai Deping , Xia Jianyang , Luo Yiqi 
Published: February 2017

AbstractSubstantial efforts have recently been made toward integrating more processes to improve ecosystem model performances. However, model uncertainties caused by new processes and/or data sets remain largely unclear. In this study, we explore uncertainties resulting from additional nitrogen (N) data and processes in a terrestrial ecosystem (TECO) model framework using a data assimilation system. Three assimilation experiments were conducted with TECO‐C‐C (carbon (C)‐only model), TECO‐CN‐C (TECO‐CN coupled model with only C measurements as assimilating data), and TECO‐CN‐CN (TECO‐CN model with both C and N measurements). Our results showed that additional N data had greater effects on ecosystem C storage (+68% and +55%) compared with added N processes (+32% and −45%) at the end of the experimental period (2009) and the long‐term prediction (2100), respectively. The uncertainties mainly resulted from woody biomass (relative information contributions are +50.4% and +36.6%) and slow soil organic matter pool (+30.6% and −37.7%) at the end of the experimental period and the long‐term prediction, respectively. During the experimental period, the additional N processes affected C dynamics mainly through process‐induced disequilibrium in the initial value of C pools. However, in the long‐term prediction period, the N data and processes jointly influenced the simulated C dynamics by adjusting the posterior probability density functions of key parameters. These results suggest that additional measurements of slow processes are pivotal to improving model predictions. Quantifying the uncertainty of the additional N data and processes can help us explore the terrestrial C‐N coupling in ecosystem models and highlight critical observational needs for future studies.
A Godunov‐type finite‐volume solver for nonhydrostatic Euler equations with a time‐splitting approach
Authors: Nazari Farshid , Nair Ramachandran D. 
Published: February 2017

AbstractA two‐dimensional conservative nonhydrostatic (NH) model based on the compressible Euler system has been developed in the Cartesian (x, z) domain. The spatial discretization is based on a Godunov‐type finite‐volume (FV) method employing dimensionally split fifth‐order reconstructions. The model uses the explicit strong stability‐preserving Runge‐Kutta scheme and a split‐explicit method. The time‐split approach is generally based on the split‐explicit method, where the acoustic modes in the Euler system are solved using small time steps, and the advective modes are treated with larger time steps. However, for the Godunov‐type FV method this traditional approach is not trivial for the Euler system of equations. In the present study, a new strategy is proposed by which the Euler system is split into three modes, and a multirate time integration is performed. The computational efficiency of the split scheme is compared with the explicit one using the FV model with various NH benchmark test cases.
Heat and water transport in soils and across the soil‐atmosphere interface: 2. Numerical analysis
Authors: Fetzer Thomas , Vanderborght Jan , Mosthaf Klaus , Smits Kathleen M. , Helmig Rainer 
Published: February 2017

AbstractIn an accompanying paper, we presented an overview of a wide variety of modeling concepts, varying in complexity, used to describe evaporation from soil. Using theoretical analyses, we explained the simplifications and parameterizations in the different approaches. In this paper, we numerically evaluate the consequences of these simplifications and parameterizations. Two sets of simulations were performed. The first set investigates lateral variations in vertical fluxes, which emerge from both homogeneous and heterogeneous porous media, and their importance to capturing evaporation behavior. When evaporation decreases from parts of the heterogeneous soil surface, lateral flow and transport processes in the free flow and in the porous medium generate feedbacks that enhance evaporation from wet surface areas. In the second set of simulations, we assume that the vertical fluxes do not vary considerably in the simulation domain and represent the system using one‐dimensional models which also consider dynamic forcing of the evaporation process, for example, due to diurnal variations in net radiation. Simulated evaporation fluxes subjected to dynamic forcing differed considerably between model concepts depending on how vapor transport in the air phase and the interaction at the interface between the free flow and porous medium were represented or parameterized. However, simulated cumulative evaporation losses from initially wet soil profiles were very similar between model concepts and mainly controlled by the desorptivity, Sevap, of the porous medium, which depends mainly on the liquid flow properties of the porous medium.
Preparation and solution performance for the amphiphilic polymers with different hydrophobic groups
Authors: Zhu Zhou , Kang Wanli , Sarsenbekuly Bauyrzhan , Yang Hongbin , Dai Caili , Yang Runmei , Fan Haiming 
Published: February 2017

ABSTRACTAn amphiphilic polymer with twin‐tailed hydrophobic groups was prepared by micellar polymerization of acrylamide as hydrophilic monomers, 2‐acryloylamino‐2‐methyl‐1‐propanesulfonic acid as functional monomers and N,N‐dodecyl acrylamide as hydrophobic monomers. Using the same method, containing single‐tailed hydrophobic group of the amphiphilic polymer and not containing the hydrophobic group of ordinary polymer were prepared. The molecular structure of the product was characterized by infrared spectrum and 1H nuclear magnetism resonance spectrum. By inclusion complexation of β‐cyclodextrin (β‐CD), the hydrophobic association on the apparent viscosity contribution rate was studied. Relationship between hydrophobic group structure and its performance was investigated by the rotational viscometer, scanning electron microscopy (SEM), fluorescence spectroscopy, and rheometer. The results showed that amphiphilic polymers containing twin‐tailed hydrophobic groups had a lower critical aggregation concentration (CAC). When the amphiphilic polymer concentration was higher than CAC, hydrophobic association was stronger, which led to a higher apparent viscosity contribution rate. At the same polymer solution concentration, amphiphilic polymer containing twin‐tailed hydrophobic group had better performance on temperature resistance, salt tolerance, and mechanical shear resistance compared with the other two polymers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44744.