bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pemahaman Konseptual Siswa Kelas VII dalam Menyelesaikan Soal SPLDV Menggunakan Metode Grafik
Authors: Annafi Awantagusnik  , Feri Prastyo  
Published: August 2024

Pemahaman konseptual merupakan sesuatu yang dimiliki seseorang untuk dapat mempelajari materi maupun tuntuk menyelesaikan masalah. Pemahaman konseptual matematika dapat dilihat melalui beberapa indikator yakni (1) Kemampuan untuk mengungkapkan kembali Konsep matematika yang sudah di pelajari, (2) Kemampuan untuk mengimplementasikan konsep matematika untuk menyelesaikan masalah dan membuat perhitungan, (3) Kemampuan untuk menggambarkan konsep dalam bentuk gambar, diagram, dan grafis. Salah satu materi matematika yang berkaitan dengan pemahaman konseptual adalah Sistem Persamaan Linier Dua Variabel (SPLDV). Terdapat beberapa metode untuk menyelesaikan soal SPLDV antara lain metode eliminasi, substitusi, eliminasi-substitusi, dan grafik. Dari keempat metode penyelesaian tersebut, metode grafik merupakan metode yang jarang digunakan oleh siswa. Padahal dengan menggunakan metode tersebut, pemahaman konseptual seseorang dapat dengan mudah dilihat terutama pada indikator ketiga. Penelitian ini merupakan penelitian kualitatif untuk mendeskripsikan pemahaman konseptual siswa kelas VII SMP dalam menyelesaikan soal SPLDV menggunakan metode grafik. Subjek penelitian dalam penelitian ini ada tiga siswa yang terdiri dari siswa dengan kemampuan tinggi, rendah, dan sedang. Siswa diberikan dua soal yang berkaitan dengan SPLDV. Berdasarkan hasil pekerjaan siswa, peneliti akan melakukan analisis data yang terdiri dari data reduction, data display, dan conclusion drawing/ verification. Hasil penelitian menunjukkan menunjukkan bahwa pemahaman konseptual siswa dalam menyelesaikan soal SPLDV dengan metode grafik masih sangat rendah. Hal ini ditunjukkan dengan indikator pemahaman konseptual yang dipenuhi hanya indikator pertama dan kedua dan masing-masing indikator tersebut hanya dipenuhi oleh satu subjek saja. Penelitian lanjutan terkait peningkatan pemahaman konseptual dalam menyelesaiakan soal SPLDV terutama dengan menggunakan metode grafik perlu untuk dilakukan. Upaya peningkatan tersebut dapat dilakukan dengan menerapkan model pembelajaran yang tepat, pembuatan media pembelajaran yang tepat maupun pembuatan bahan ajar yang tepat.
Keywords: Pemahaman konseptual, SPLDV, penyelesaian masalah, metode grafik
Crítica husserliana do conhecimento à filosofia transcendental de Kant
Authors: Senra André Vinícius Dias 
Published: August 2024

De acordo com o método de Husserl, a superação do psicologismo torna-se necessária não somente para resolver o problema de fundação da Teoria do Conhecimento, mas também indica necessidade de estabelecer a fundação fenomenológica do conhecimento como base epistêmica que revela a possibilidade de fundar a esfera ideal da objetividade. Principalmente, porque a Fenomenologia pretende ser a ciência filosófica por excelência, na medida em que possa ser caracterizada como tal em função da constituição transcendental da cientificidade filosófica. A constituição fenomenológica da ciência de rigor (strenge wissenschaft) se torna possível em função de duas críticas de Husserl a Kant, posto que este disporia de um conceito limitado de fenômeno: 1) para Husserl, Kant não conseguiu conceber que o caminho transcendental poderia ser a base epistêmica segura para o desenvolvimento da ciência filosófica; 2) e, também, como Kant não investiu no desenvolvimento do sentido transcendental, desconhecendo a tarefa fenomenológica, terminou por não perceber a noção de intencionalidade como necessária para fundar a subjetividade transcendental, como base para a ciência filosófica, e, sem ela, desconheceu o sentido ideal da vivência intencional como campo fenomenológico.
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

AbstractTo 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

AbstractSeveral 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

AbstractInterpretations 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

AbstractWe 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

AbstractAnalog 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

AbstractThe 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

AbstractEastern 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

AbstractDetails 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

AbstractThis 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

AbstractThis 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

AbstractA 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.