bluuebunny/crossref_metadata_2025 huggingface dataset:
Upper-mantle shear velocities beneath southern California determined from long-period surface waves
Authors: Polet J. , Kanamori H.
Published: September 2021

We used long-period surface waves from teleseismic earthquakes recorded by the TERRAscope network to determine phase velocity dispersion of Rayleigh waves up to periods of about 170 sec and of Love waves up to about 150 sec. This enabled us to investigate the upper-mantle velocity structure beneath southern California to a depth of about 250 km. Ten and five earthquakes were used for Rayleigh and Love waves, respectively. The observed surface-wave dispersion shows a clear Love/Rayleigh-wave discrepancy that cannot be accounted for by a simple isotropic velocity model with smooth variations of velocity with depth. Separate isotropic inversions for Love- and Rayleigh-wave data yield velocity models that show up to 10% anisotropy (transverse isotropy). However, tests with synthetic Love waves suggest that the relatively high Love-wave phase velocity could be at least partly due to interference of higher-mode Love waves with the fundamental mode. Even after this interference effect is removed, about 4% anisotropy remains in the top 250 km of the mantle. This anisotropy could be due to intrinsic anisotropy of olivine crystals or due to a laminated structure with alternating high- and low-velocity layers. Other possibilities include the following: upper-mantle heterogeneity in southern California (such as the Transverse Range anomaly) may affect Love- and Rayleigh-wave velocities differently so that it yields the apparent anisotropy; higher-mode Love-wave interference has a stronger effect than suggested by our numerical experiments using model 1066A. If the high Love-wave velocity is due to causes other than anisotropy, the Rayleigh-wave velocity model would represent the southern California upper-mantle velocity structure. The shear velocity in the upper mantle (Moho to 250 km) of this structure is, on average, 3 to 4% slower than that of the TNA model determined for western North America.
The Kozani-Grevena (Greece) earthquake of 13 May 1995 revisited from a detailed seismological study
Authors: Hatzfeld D. , Karakostas V. , Ziazia M. , Selvaggi G. , Leborgne S. , Berge C. , Guiguet R. , Paul A. , Voidomatis P. , Diagnourtas D. , Kassaras I. , Koutsikos I. , Makropoulos K. , Azzara R. , Di Bona M. , Baccheschi S. , Bernard P. , Papaioannou C.
Published: September 2021

The Kozani earthquake (Ms = 6.6) of 13 May 1995 is the strongest event of the decade in Greece and occurred in a region of low seismic activity. Using regional data and the strong-motion record at the Kozani station, we relocate the mainshock at 40.183° N and 21.660° E, beneath the Vourinos massif at a depth of 14.2 km. We also compute a focal mechanism by body-waveform modeling at teleseismic distance, which confirms a normal mechanism. The most likely plane strikes 240° ± 1° N and dips 40° ± 1° N with a centroid depth of 11 ± 1 km. Modeling of the strong-motion record at Kozani confirms that nucleation started at the eastern termination of the bottom of the fault.

Six days after the mainshock, we installed a network of 40 portable seismological stations for one week around the epicentral region. Several thousand aftershocks were recorded, among which we locate 622 with a precision better than 1 km. We compute 181 focal mechanisms that mostly show normal faulting. The aftershock seismicity is restricted between 5 and 15 km depth and defines a plane dipping north at an angle of about 35°, consistent with the mainshock mechanism. Seismic activity with the same pattern of normal fault mechanisms is also seen on an antithetic fault connected to the main one at 12 km depth, which cuts the ground surface north of the Vourinos ophiolite massif in the Siatista valley. These results suggest two possibilities for the active fault plane; either it is the Deskati fault that is flat and dips with a constant angle, and therefore the surface breaks are secondary features, or, more likely, it is the Paleohori fault that is new, of listric shape, and located ahead of the Deskati fault, which was not active during the earthquake.
Toward a homogeneous moment-magnitude determination for earthquakes in Greece and the surrounding area
Authors: Papazachos B. C. , Kiratzi A. A. , Karacostas B. G.
Published: September 2021

A strategy is presented in order to produce a statistically homogeneous catalog of historical and present-century earthquakes of the Aegean area by expressing the size of all these earthquakes in the moment-magnitude scale. Records of the Mainka and Wiechert intermediate period (T0 ∼ 4 sec) seismographs in Athens have been used to calculate the magnitudes of earthquakes that occurred in Greece and its surrounding area (Albania, S. Yugoslavia, S. Bulgaria, and W. Turkey) during the whole instrumental period (since 1911). This magnitude, M, has also been used to derive empirical relations with macroseismic data. It is shown here that M is equivalent to moment magnitude, MW, for a wide range of earthquake sizes (5.0 ≦ M ≦ 8.0), and to the surface-wave magnitude, MS, for large earthquake sizes (6 ≦ M ≦ 8.0). It is also shown that the local magnitude, ML, for earthquakes in Greece is half a unit smaller than the moment magnitude in the low-magnitude range (4.5 ≦ ML ≦ 6.0). This could be attributed to a magnification smaller than the nominal for the Wood-Anderson seismographs in Greece (V ∼ 1000). Relations are also proposed to calculate moment magnitude when other magnitudes (M, ML, MS, and mb) are known for earthquakes in Greece.
Analysis of topographic amplification of inclined shear waves in a steep coastal bluff
Authors: Ashford Scott A. , Sitar Nicholas
Published: September 2021

The effect of inclined shear waves on the seismic response of a steep bluff is analyzed using generalized consistent transmitting boundaries. The results of the frequency-domain analysis of a stepped half-space subjected to incident shear waves inclined from 0° to 30° show that the motion at the crest of the slope is amplified for waves traveling into the slope and attenuated for waves traveling away from the slope, as compared to the motion in the free field behind the crest of the slope. This amplification can be as much as twice that observed for vertically propagating waves. A time-domain analysis of bluffs at Seacliff State Beach, California, is used to estimate the effect of topography using realistic conditions, taking into account wave inclination and site effects. The analysis of the site shows that although topographic amplification does in fact nearly double the amplitude of the motion in some cases, this amplification is offset by reduced site amplification and by wave splitting at material interfaces. Thus, the actual peak acceleration occurring at the crest of the slope changes little with incident angle as compared to the amplification of the free-field motion and actually decreases in many cases. Though a more general study is recommended, these results suggest that wave orientation and inclination substantially increase topographic amplification; however, it may be adequate to only account for vertically propagating waves for site response and slope stability analyses where only the magnitude of acceleration is considered.
The large aftershocks of the Northridge earthquake and their relationship to mainshock slip and fault-zone complexity
Authors: Dreger Douglas
Published: September 2021

The distribution of fault slip for the Northridge mainshock and two MW ≧ 6 aftershocks is estimated using an approach that inverts the far-field momentrate functions derived by empirical Green's function deconvolution. The slip for these events was found to have a strong negative correlation with the locations of small aftershocks, and there is a notable clustering of aftershocks near the edges of slip, suggesting that these events are triggered by a redistribution of stress following the mainshock rupture. The two largest aftershocks ruptured the updip regions adjacent to the leading edge of the mainshock rupture. One aftershock, 11 hr after the main event, initiated 8 km west of the mainshock slip terminus and ruptured east to the western edge of mainshock slip. This event was found to have ruptured the same south-dipping fault as the mainshock. The two events, however, are separated by a lateral offset in the depth of seismicity that serves as a geometrical barrier to through-going rupture. An MW 6.2 aftershock approximately 1 min after the main event is inferred to have ruptured an updip region of the mainshock fault that is relatively devoid of small aftershock seismicity. This event was located at the eastern edge of the sequence that overlaps with the north-dipping fault responsible for the 1971 San Fernando earthquake. Although the south-dipping plane is favored for this aftershock, it is not possible to rule out that it occurred on the north-dipping fault structure, or within the hanging block of the mainshock.
Surface strain accumulation and the seismic moment tensor
Authors: Savage J. C. , Simpson R. W.
Published: September 2021

Although the scalar moment accumulation rate within the seismogenic zone beneath a given area is sometimes deduced from the observed average surface strain accumulation rate over that same area (e.g., Working Group on California Earthquake Probabilities, 1995), the correspondence between the two is very uncertain. The equivalence between surface strain accumulation and scalar moment accumulation is based on Kostrov's (1974) relation between the average strain rate over a volume and the moment-rate tensor for that volume. The average strain rate over the volume is replaced by the average strain rate measured at the free surface to deduce an approximate moment-rate tensor. Only in exceptional circumstances will that moment-rate tensor correspond to a double-couple mechanism, a mechanism that can be represented by a scalar moment accumulation rate. More generally, the moment tensor must be resolved into the superposition of two or more double-couple mechanisms, and that resolution can be done in many ways, each with its own scalar moment rate. Thus the resolution is not unique. This is demonstrated by deducing scalar moment accumulation rates for a GPS network that covers most of California south of San Francisco. It is shown that resolutions into different double-couple mechanisms lead to scalar moment accumulation rates differing by factors of ∼2. We suggest that the minimum scalar moment rate equivalent to principal surface strain rates ɛ1 and ɛ2 acting over the area A is M0(min) = 2μHA Max (¦ɛ1¦, ¦ɛ2¦, ¦ɛ1 + ɛ2¦), where μ is the rigidity and H the depth of seismogenic zone, and the function Max is equal to the largest of its arguments. Within the uncertainites of measurement, the scalar moment accumulation rate in southern California based on that approximation is in balance with the average historic seismic moment release rate so that no current earthquake deficit need be accumulating.
Seismicity at Warna reservoir (near Koyna) through 1995
Authors: Rastogi B. K. , Chadha R. K. , Sarma C. S. P. , Mandal P. , Satyanarayana H. V. S. , Raju I. P. , Kumar Narendra , Satyamurthy C. , Nageswara Rao A.
Published: September 2021

The Koyna Dam site in western India has been seismically active since its impounding in 1962. The seismicity peaked in 1967 when an earthquake of magnitude 6.3 claimed 200 human lives and caused some damage to the dam itself. Subsequently, bursts of seismicity with M ≧ 5 earthquakes have occurred during 1973, 1980, and 1993 to 1995. The epicenters during the latest burst are concentrated around the newly impounded Warna reservoir, 25 km south of Koyna. Several shocks of smaller magnitude have occurred in this area since 1967 under the influence of the Koyna (Shivajisagar) reservoir, but the impoundment of the Warna reservoir to over 60 m has led to the enhanced seismic activity in the region. The space-time pattern of epicenters located for the period 28 August 1993 to 31 December 1995 clearly delineates two parallel trends in the NNE-SSW direction. The correlation between seismic activity and water levels in both the reservoirs suggests that the present activity was influenced more by the Warna than the Koyna reservoir. The discriminatory characteristics of reservoir-induced seismicity based on b-value, foreshock-aftershock pattern, and decay rate of aftershocks continue to be valid.
An analysis of seismic and acoustic signals measured from a series of atmospheric and near-surface explosions
Authors: Kitov I. O. , Murphy J. R. , Kusnetsov O. P. , Barker B. W. , Nedoshivin N. I.
Published: September 2021

During December 1985, Soviet scientists monitored a series of high-explosive tests at a bombing range near Kustanai, Kazakhstan, in which both seismic and acoustic data were recorded at distances of 6, 9.5, and 21 km from bomb blasts at different altitudes. These data show a remarkable variety of seismo/acoustic phenomena associated with energy conversion processes at the Earth's surface, including air-coupled Rayleigh waves and acoustic signals produced by propagating seismic disturbances having phase velocities near the speed of sound in air. These data provide valuable new insights into the mechanisms responsible for the generation of seismic and acoustic signals by atmospheric and near-surface explosions. In particular, theoretical simulation results are presented that are shown to account for most of the features of the observed data, and, therefore, it is concluded that the simplified theoretical models employed in these simulations can provide a quantitative basis for assessing the effects of source and site conditions on the characteristics of the signals produced by such explosions.
Topographic site effects. A comparison of two nonreference methods
Authors: Chávez-García Francisco J. , Rodríguez Miguel , Field Edward H. , Hatzfeld Denis
Published: September 2021

We present an experimental study of topographic site effects. The data we use come from an experiment carried out during the summer of 1989, in Epire (northern Greece). Ten digital stations recorded a total of 68 small earthquakes. A recent article (Chávez-García et al., 1996) presented a comparison between site effects determined using horizontal-to-vertical spectral ratios (HVSR) for this data set and theoretical modeling. In this note, we compare the topographic site effects determined using HVSR with another, independent, experimental estimate: a generalized inversion scheme (GIS). Neither HVSR nor GIS depend on the availability of a reference site. We obtain a very good agreement between both estimates of topographic site effects for both horizontal components. Our results support the use of HVSR to determine topographic site effects.
Accuracy analysis of the split-step Fourier propagator: Implications for seismic modeling and migration
Authors: Huang Lian-Jie , Fehler Michael C.
Published: September 2021

The split-step Fourier propagator is a one-way wave propagation method that has been widely used to simulate primary forward and backward (reflected) deterministic/random wave propagation due to its fast computational speed and limited computer memory requirement. The method is useful for rapid modeling of seismic-wave propagation in heterogeneous media where forward scattered waveforms can be considered to be dominant or reverberations can be ignored. The method is based on a solution to the one-way wave equation that requires expanding the square root of an operator and splitting of the resulting noncommutative operators to allow calculation by transferring wave fields between the space and wavenumber domains. Previous analysis of the accuracy of the method has focused on the error related to only a portion of the approximations involved in the propagator. To better understand the accuracy of the propagator, we present a complete formal and numerical accuracy analyses. Our formal analysis indicates that the dominant error of the propagator increases as the first order in the marching interval. We show that nonsymmetrically and symmetrically split-step marching solutions have the same first-order error term. Their second- and third-order error terms are similar. Therefore, the differences between the accuracy of different split-step marching solutions are insignificant. This conclusion is confirmed by our numerical tests. The relation among the phase error of the split-step Fourier propagator, relative velocity perturbation, and propagation angle is numerically studied. The results suggest that the propagator is accurate for up to a 60° propagation angle from the main propagation direction for media with small relative velocity perturbations (10%).
Statistical analysis of irregular wave-guide influences on regional seismic discriminants in China
Authors: Fan Guangwei , Lay Thorne
Published: September 2021

Short-period regional phases play an important role in identifying low-magnitude seismic events in the context of monitoring the Comprehensive Test Ban Treaty. Amplitude ratios of regional phases comprised mainly of P-wave energy (Pn, Pg) to those comprised mainly of S-wave energy (Sn, Lg) effectively discriminate between explosions and earthquakes in many regions, particularly at frequencies higher than 3 Hz. At lower frequencies, discrimination is usually poor due to large scatter that causes overlapping of event populations. Scatter in regional discriminant measures such as Pg/Lg ratios is caused by both source and propagation effects, and reducing the scatter imparted by the latter is essential to improving the discriminant performance when events do not share identical paths. Regional phases experience distance-dependent amplitude variations due to effects such as critical angle amplification, geometric spreading, and attenuation. Discriminant measures are usually corrected for empirically determined distance trends for a given region, but large scatter persists after such corrections. This study seeks to develop more sophisticated empirical corrections for path properties in order to further reduce the scatter in regional discriminant measures caused by propagation effects. Broadband seismic waveforms recorded at station WMQ, in western China, demonstrate that regional Pg/Lg ratios show significant distance dependence for frequencies less than 6 Hz. However, variations in crustal structure cause additional path-specific amplitude fluctuations that are not accounted for by regionally averaged distance corrections. Blockage of Lg phases on paths traversing the margins of the Tibetan Plateau is one such effect. Regression analysis demonstrates that Pg/Lg ratios measured at WMQ display significant correlations with path-specific properties such as mean elevation, topographic roughness, basement depth, and crustal thickness. Multiple regressions using optimal combinations of parameters yield corrections that reduce variance in Pg/Lg measurements for frequencies less than 3 Hz by a factor of 2 or more relative to standard distance corrections. This should systematically enhance the performance of the Pg/Lg discriminant at low frequencies. The method presented here can be used for all regions and all short-period regional discriminants. It is likely that the extraordinary crustal heterogeneity in western China represents an extreme case of path-dependent effects.
Seismicity alert probabilities at Parkfield, California, revisited
Authors: Michael Andrew J. , Jones Lucile M.
Published: September 2021

For a decade, the U.S. Geological Survey has used the Parkfield Earthquake Prediction Experiment scenario document to estimate the probability that earthquakes observed on the San Andreas fault near Parkfield will turn out to be foreshocks followed by the expected magnitude 6 mainshocks. During this time, we have learned much about the seismogenic process at Parkfield, about the long-term probability of the Parkfield mainshock, and about the estimation of these types of probabilities. The probabilities for potential foreshocks at Parkfield are reexamined and revised in light of these advances. As part of this process, we have confirmed both the rate of foreshocks before strike-slip earthquakes in the San Andreas physiographic province and the uniform distribution of foreshocks with magnitude proposed by earlier studies. Compared to the earlier assessment, these new estimates of the long-term probability of the Parkfield mainshock are lower, our estimate of the rate of background seismicity is higher, and we find that the assumption that foreshocks at Parkfield occur in a unique way is not statistically significant at the 95% confidence level. While the exact numbers vary depending on the assumptions that are made, the new alert probabilities are lower than previously estimated. Considering the various assumptions and the statistical uncertainties in the input parameters, we also compute a plausible range for the probabilities. The range is large, partly due to the extra knowledge that exists for the Parkfield segment, making us question the usefulness of these numbers.
Faulting along the southern margin of Reelfoot Lake, Tennessee
Authors: Arsdale Roy Van , Purser Jodi , Stephenson William , Odum Jack
Published: September 2021

The Reelfoot Lake basin, Tennessee, is structurally complex and of great interest seismologically because it is located at the junction of two seismicity trends of the New Madrid seismic zone. To better understand the structure at this location, a 7.5-km-long seismic reflection profile was acquired on roads along the southern margin of Reelfoot Lake. The seismic line reveals a westerly dipping basin bounded on the west by the Reelfoot reverse fault zone, the Ridgely right-lateral transpressive fault zone on the east, and the Cottonwood Grove right-lateral strike-slip fault in the middle of the basin. The displacement history of the Reelfoot fault zone appears to be the same as the Ridgely fault zone, thus suggesting that movement on these fault zones has been synchronous, perhaps since the Cretaceous. Since the Reelfoot and Ridgely fault systems are believed responsible for two of the main-shocks of 1811-1812, the fault history revealed in the Reelfoot Lake profile suggests that multiple mainshocks may be typical of the New Madrid seismic zone.

The Ridgely fault zone consists of two northeast-striking faults that lie at the base of and within the Mississippi Valley bluff line. This fault zone has 15 m of post-Eocene, up-to-the-east displacement and appears to locally control the eastern limit of Mississippi River migration. The Cottonwood Grove fault zone passes through the center of the seismic line and has approximately 5 m of up-to-the-east displacement. Correlation of the Cottonwood Grove fault with a possible fault scarp on the floor of Reelfoot Lake and the New Markham fault north of the lake suggests the Cottonwood Grove fault may change to a northerly strike at Reelfoot Lake, thereby linking the northeast-trending zones of seismicity in the New Madrid seismic zone.
Array measurements of phases used in receiver-function calculations: Importance of scattering
Authors: Abers Geoffrey A.
Published: September 2021

Receiver-function methods utilize three-component teleseismic P coda to determine structure beneath seismographs. Most methods treat coda complexity as mode conversions and reflections off subhorizontal interfaces beneath the station, such as the Moho. This assumption is evaluated beneath a broadband array in the Kopet Dagh foothills, at Geyokcha, Turkmenistan, by applying array processing techniques to P coda waves at frequencies near 1 Hz. Beneath the Geyokcha array, horizontal components show signals that deviate significantly in slowness and bearing from predictions of a plane-layered Earth. Large phases arrive at the same time as the predicted Ps conversion from the Moho yet systematically come from a single azimuth (from NNE) and travel at phase velocities of 3 to 5 km/sec. The coda waves appear to be P-to-S converted waves from a near-surface scatterer. An inversion for scatterer location is developed and applied to 29 events. Most coda energy comes from a scatterer ∼16 km NNE of the array. This location is coincident with the range-bounding faults that separate Kopet Dagh mountains from adjacent basins. Thus, array analysis shows that signals potentially interpreted as Moho conversions are instead scattered from a near-surface structure. Although these results suggest caution is necessary in interpreting single-station receiver functions, particularly at high frequencies, they also demonstrate the power of array sampling in resolving lateral structure variations.
Three-dimensional simulation of the near-fault ground motion for the 1995 Hyogo-Ken Nanbu (Kobe), Japan, earthquake
Authors: Pitarka Arben , Irikura Kojiro , Iwata Tomotaka , Sekiguchi Haruko
Published: September 2021

The 17 January 1995 Hyogo-ken Nanbu earthquake is a typical example showing that the ground motions along basin-edge faults can be very destructive. In this study, we simulate the near-fault ground motion from this earthquake based on a kinematic fault model and a simplified 3D velocity structure of the Kobe area. The kinematic earthquake rupture and the wave propagation are modeled using a 3D finite-difference method (FDM). Our simulation identifies the basin-edge effect as an important factor that influenced the ground-motion amplification pattern in the Kobe area. We found that the coupling of the source directivity and basin-edge effects causes impulsive ground motions with extremely high amplitude at periods greater than 1 sec and in a narrow zone offset less than 1 km from the basin edge. The combination of these effects acted to create a fairly continuous band of amplification that extends about 30 km in an elongated zone parallel to the basin-edge boundary. In some areas, localized site effects might have been as important as the abovementioned effects, but they cannot explain the continuity of the extended east-west zone of damage.
Regionalized versus single-station wave-guide effects on seismic discriminants in western China
Authors: Fan Guangwei , Lay Thorne
Published: September 2021

Regional seismic signals play an important role in identifying low-magnitude explosion and earthquake sources for monitoring the Comprehensive Test Ban Treaty (CTBT). To enhance the performance of seismic discriminants, regional phases need to be corrected for propagation effects of large- and intermediate-scale crustal wave-guide heterogeneity. Multivariate regression analysis using parametric path characteristics has shown promise for reducing the propagation-induced scatter in short-period regional phase amplitude ratios. While path length is an important parameter for most seismic phase amplitudes, other parametric features of crustal wave-guide structure are often significantly correlated with regional amplitude ratios of P-wave energy (Pn, Pg) to S-wave energy (Sn, Lg) as demonstrated by our prior work on station WMQ. A question remains as to whether these effects can be regionalized so that they apply to all observations in a given region. We explore the viability of regionalization of wave-guide effects on regional seismic discriminants for frequencies of 0.75 to 6 Hz in central Asia and southwest China by analyzing single- and multi-station data. Linear regressions for single-station data indicate that the significance of specific path parameters extracted from available crustal models varies from one station to another and from one subregion to another. In general, corrections for optimal combinations of wave-guide parameters obtained from multivariate regression reduce the data variance more than conventional corrections for path length alone for both single-station and multi-station data. However, in central Asia, several stations show path dependence on certain variables with opposite signs, so regionalization with multi-station data does not perform well. This is due to highly path-specific effects. In southwest China, there is greater commonality in behavior among stations, and fairly good regionalization can be achieved. However, the resulting variance reduction is still less than that for individual stations because some path effects appear to be direction dependent. Our results indicate that individual station calibration is the preferred procedure, but this should include corrections for path effects beyond simple distance correction.
Nonstationary Bayesian kriging: A predictive technique to generate spatial corrections for seismic detection, location, and identification
Authors: Schultz Craig A. , Myers Stephen C. , Hipp James , Young Christopher J.
Published: September 2021

Seismic characterization works to improve the detection, location, and identification of seismic events by correcting for inaccuracies in geophysical models. These inaccuracies are caused by inherent averaging in the model, and, as a result, exact data values cannot be directly recovered at a point in the model. Seismic characterization involves cataloging reference events so that inaccuracies in the model can be mapped at these points and true data values can be retained through a correction. Application of these corrections to a new event requires the accurate prediction of the correction value at a point that is near but not necessarily coincident with the reference events. Given that these reference events can be sparsely distributed geographically, both interpolation and extrapolation of corrections to the new point are required. In this study, we develop a closed-form representation of Bayesian kriging (linear prediction) that incorporates variable spatial damping. The result is a robust nonstationary algorithm for spatially interpolating geophysical corrections. This algorithm extends local trends when data coverage is good and allows for damping (blending) to an a priori background mean when data coverage is poor. Benchmark tests show that the technique gives reliable predictions of the correction value along with an appropriate uncertainty estimate. Tests with travel-time residual data demonstrate that combining variable damping with an azimuthal coverage criterion reduces the large errors that occur with more classical linear prediction techniques, especially when values are extrapolated in poor coverage regions. In the travel-time correction case, this technique generates both seismic corrections along with uncertainties and can properly incorporate model error in the final location estimate. Results favor the applicability of this nonstationary algorithm to other types of seismic corrections such as amplitude and attenuation measures.
Çevrimiçi Kuponların ve Tek Tuşla Ödeme İşlem Kolaylığının Çevrimiçi Plansız Satın Alma Üzerine Etkisi
Authors: ÖZTÜRK Abdülkadir , KIRMIZIKAYA Arif , AKIN Mustafa Said
Published: September 2021

Teknolojik gelişmeler ile beraber tüketicilerin alışveriş davranışları ve ödeme alışkanlıklarında değişimler meydana gelmektedir. Kuponlar ve indirimler kazanma duygusuyla birlikte mutluluğa yol açabilmektedir. Çevrimiçi kuponlar da son zamanlarda çevrimiçi işletmeler tarafından tüketicilerine yaygın olarak sunulmaktadır. Bu çalışmanın amacı çevrimiçi kuponların, tek tuşla ödeme işlem kolaylığı ile çevrimiçi plansız satın alma üzerine etkisinin araştırılmasıdır. Araştırma için gerekli veriler, hazırlanan çevrimiçi anket formu aracılığıyla ve 423 kişinin katılımıyla toplanmıştır. Araştırmada kullanılan ifadelerin geçerliliği ve güvenilirliği için açıklayıcı ve doğrulayıcı faktör analizi ile yapılmıştır. Anket formunun linki araştırmacılar tarafından daha önce çevrimiçi alışveriş yapmış kişilere ulaştırılmıştır. Araştırmacılar, yeterli örneklem sayısına ulaşabilmek için ankete katılanlardan daha önce çevrimiçi alışveriş yapmış arkadaşlarıyla bu linki paylaşmalarını istemiştir. İşletmelerin tüketicilerine sunmuş oldukları çevrimiçi kuponlar hem tek tuşla ödeme işlem kolaylığı hem de çevrimiçi plansız satın alma üzerinde etkili olduğu belirlenmiştir.
Центробежная свс-металлургия жаропрочных сплавов
Authors: Юхвид В.И. , Андреев Д.Е. , Санин В.Н. , Икорников Д.М.
Published: September 2021

Проведен обзор результатов, полученных авторами по синтезу литых жаропрочных сплавов методами СВС-металлургии. Основное внимание уделено синтезу жаропрочных сплавов на основе интерметаллидов никеля и титана, кобальта и силицидов ниобия. Определены параметры, позволяющие управлять процессами горения исходных смесей термитного типа, гравитационной сепарацией в расплаве продуктов горения, формированием состава и структуры литых жаропрочных сплавов.
Practicing Communicative Language Teaching Approach of English Grammar Teaching: Teachers’ Perspectives in China Colleges
Authors: Tianli Zhou , Mansor Nor Shahila , Ang Lay Hoon , Sharmini Sharon
Published: September 2021

The communicative language teaching (CLT) approach has been extensively used in English teaching in recent decades. Many scholars have investigated CLT and English teaching from various perspectives, but few have examined teachers’ attitudes towards the CLT approach and its usage in English grammar teaching. This study aimed to investigate the rationale, the teaching effects and suggestions of English teachers in using CLT in English grammar teaching in China colleges. A qualitative research method was adopted and data was collected through an open-response questionnaire from 13 English teachers of 6 universities in China. The analysis of the data collected revealed that most of the China English teachers used CLT. Their rationale for using it are summarized in this study. The results show that CLT positively affects China college students’ English grammar learning despite some limitations, especially in cultivating their communicative competence, motivating their study interests, and modifying the classroom atmosphere, which also helps build students’ confidence. Moreover, most of the participants recommended using CLT to conduct English grammar teaching, and eight suggestions were presented to help English teachers conduct the CLT approach to grammar teaching. This study could prove a good reference for teachers who would like to teach English grammar under the CLT approach and enhance their understanding of CLT.
Organic Agriculture: Farmers Perception and Adaptation in Northern Thailand
Authors: Jiumpanyarach Waripas
Published: September 2021

This study aimed to examine factors impacting on farmers’ decision to convert from conventional to organic agriculture in Phayao and Nan Provinces, Thailand. The perceptions in conversion from conventional agriculture to organic agriculture toward the intention to change behavior, attitudes, and decision-making were analyzed. The data were collected by questionnaires administered to 124 farmers. The theory of planned behavior and the impacting factors of farm practices using logit model were used for analysis. The reasons for adopting organic agriculture were separated into three categories: (1) knowledge and understanding; farmers understood healthy farming but had little organic farm management information; (2) farm size impacts the costs of production; and (3) farm economics, including costs of delivery, storage, and markets, were a barrier to organic farming. These influenced attitudes, group norms, and perceived behavior. The study found that 50% of farmers using conventional practices were unwilling to change their practices, 16.1% had not decided, but 25.8% decided to change to organic practices. Organic agriculture in the study area increased to approximately 30.65%. The study suggests that farmers’ long-term benefits were implementation of agricultural policies supporting equipment, financial resources, knowledge, green technologies, training, and extension.
Ensino de astronomia nos anos iniciais a partir das novas diretrizes da Base Nacional Comum Curricular
Authors: Oliveira Elrismar Auxiliadora Gomes , Amantes Amanda
Published: September 2021

As orientações para o ensino de Astronomia nos anos iniciais são contraditórias em documentos oficiais da educação brasileira – não são recomendados pelos Parâmetros Curriculares Nacionais (PCN), mas estão entre os critérios de avaliação do Programa Nacional do Livro e do Material Didático (PNLD). Recentemente foi aprovada a Base Nacional Comum Curricular (BNCC), documento normatizador que muda a estrutura de toda a educação básica brasileira. Suas determinações podem trazer mudanças significativas nos currículos de Ciências e nos livros didáticos. Diante desse cenário, apresentamos uma pesquisa documental, que visa identificar na BNCC o encaminhamento do ensino dos conteúdos de Astronomia nos anos iniciais. Os resultados apontam que a maior parte dos assuntos de Astronomia são determinados pela BNCC para o ensino nos anos iniciais do ensino fundamental. Porém, conteúdos que exigem maior grau de abstração e habilidade espacial para sua compreensão como, por exemplo, estações do ano e fases da Lua, não foram indicados. Quanto à forma de abordagem, atividades de observação direta dos astros e de fenômenos celestes integram o desenvolvimento desses conhecimentos na BNCC.
Developing New Things: Implications of the Platform Economy for Intrapreneurship
Authors: Schmidt Constantin , Tewes Stefan
Published: September 2021

The following paper deals with the implications of the platform economy for intrapreneurship. It is becoming increasingly difficult for traditional pipeline companies to keep up with the speed of platform companies. They are innovative, agile, and ready for change, while their legacy counterparts are the opposite. In this paper, sources from the platform economy and intrapreneurship are analyzed and evaluated using qualitative research methods. The focus is on the question of what the structure of the platform enterprise must look like for the intrapreneur to unfold his creative potential. The results show that the intrapreneur needs structural autonomy and distinctive communication structures to act successfully. Within these structures moves the intrapreneur, considered an entrepreneur and a central driver for change and innovation. Based on the results, a structural model is derived and visualized, which concretizes the findings.
Polityka personalna a relacje międzyludzkie
Authors: Januszkiewicz Katarzyna
Published: September 2021

Celem autorki niniejszego rozdziału jest wskazanie, jak zmiany w zakresie polityki personalnej (stosunku do pracownika, rozumienia jego roli etc.) wpływają na zachowania organizacyjne. Dlatego też, zgodnie z założeniami opracowania, poniżej omówione zostaną modele polityki personalnej, charakterystyczne dla organizacji określanych jako tradycyjne, współczesne i przyszłości, przy czym podział ten ma charakter umowny. Każda z części tego rozdziału składa się z trzech elementów: analizy najważniejszych koncepcji i tendencji charakterystycznych dla danego okresu, w których należy upatrywać źródeł danego modelu, omówienia wybranych obszarów polityki personalnej wynikających z modelu oraz dywagacji na temat ich konsekwencji dla zachowań ludzi w organizacji.
Ewolucja form pracy zespołowej
Authors: Michalak Joanna Malgorzata
Published: September 2021

Praca jest związana z działalnością człowieka od początków jego aktywności wytwórczej. Stopniowo, gdy aktywność ta stawała się procesem coraz bardziej złożonym, pojawiła się konieczność jej podziału i stworzenia warunków dla pracy wykonywanej przez więcej niż jedną osobę. Niniejszy rozdział poświęcony jest, z jednej strony, historycznemu prześledzeniu drogi ewolucji grupowych form organizacji działalności wytwórczej wraz z ambitną próbą projekcji form wyłaniających się, z drugiej zaś, analizie wpływu tychże form na zachowania organizacyjne pracowników.
Konsekwencje zmian dla zachowań organizacyjnych
Authors: Januszkiewicz Katarzyna , Bednarska-Wnuk Izabela , Czajkowska Maria , Kołodziejczak Małgorzata , Michalak Joanna Małgorzata , Świątek-Barylska Ilona , Zalewska-Turzyńska Magdalena
Published: September 2021

Przyjęcie zróżnicowanych perspektyw w procesie analizy pozwala autorkom na sformułowanie wniosków na temat najbardziej symptomatycznych konsekwencji zmian charakterystyki organizacji, które z pewnością nie wyczerpują całości zagadnienia, pozwalają jednak na ukazanie kierunku, w jakim ewaluują zachowania ludzi w organizacji.
Responsabilité civile en droit des sociétés en France
Authors: Kenfack Hugues
Published: September 2021

Etre une société, c’est précisément être responsable, du moins en droit français? Le raccourci serait trop rapide, même si la société est vraiment le socle de la responsabilité civile. Quelles sont donc les manifestations de la responsabilité civile en droit des sociétés en France ? Il est possible de répondre que ce sont les mêmes qu’en Pologne, ce qui faciliterait la tâche. D’emblée, une limitation du sujet s’impose. D’une part, convient-il de se limiter aux sociétés commerciales ou d’y englober les sociétés civiles? Même dans le cadre de ce débat, et en envisageant uniquement les sociétés commerciales, leur diversité est grande en droit français: sociétés anonymes, sociétés à responsabilité limitée, société par action simplifiée, sociétés en nom collectif, ou même société européenne…, avec des règles et des responsabilités différentes : laquelle privilégier? Convient-il de n’envisager que les sociétés in bonis ou faut-il y inclure les sociétés en difficult en difficulté?
La responsabilité de la société-mère pour la faute de la filiale
Authors: Popiołek Wojciech
Published: September 2021

La règle d’autonomie juridique des sociétés de capitaux – résultant de la conception de l’essence de la personnalité juridique adoptée en droit polonais – est considérée comme l’une des règles fondamentales du droit des sociétés commerciales. Elle se manifeste par l’autonomie juridique réciproque de la société de capitaux et de ses associés. Il en est de même en ce qui concerne les sociétés fonctionnant dans les groupes de sociétés, où la société dominante (société-mère) est un associé dominant de la société dépendante (filiale). Le rapport de domination ne conduit pas à la suppression de la règle d’autonomie de la société et de son associé.
Frecuencias y concentraciones de agroquímicos y su impacto en los costos de producción del cultivo de papa
Authors: Guevara Gómez Gabriel Emilio
Published: September 2021

La presente investigación, tiene como objetivo evaluar el comportamiento del nivel de incidencia de cuatro problemas fitosanitarios Phytophthora infestans, Alternaria solani, Phthorimaea operculella y nematodos, ante el combate químico que realiza un productor de papa (Solanum tuberosum) en una finca1 productora de papa del sector de Tierra Blanca de Cartago; así como la influencia que tiene el combate de problemas fitosanitarios en el costo productivo. Se realizó una investigación del alcance descriptivo y de campo, donde se midió semanalmente durante el ciclo productivo de la papa la cantidad de plantas sanas y las plantas con síntomas de presencia de Phytophthora infestans y Alternaria solani, cantidad de individuos capturados de Phthorimaea operculella. Además, se realizaron en semana 0, 10 y 15 del ciclo un diagnóstico de nematodos en suelo, para evaluar el comportamiento poblacional durante el ciclo productivo. Se registraron los tipos de agroquímicos, su concentración y cantidad aplicada en el cultivo, la frecuencia en que se realizaron las aplicaciones y el costo asociado a estas aplicaciones. Los resultados principales obtenidos fueron que establecer el cultivo en época seca favorece a disminuir el nivel de incidencia de las enfermedades fúngicas, pero aumenta la incidencia de Phthorimaea operculella; la utilización racional de insecticidas a base de Benzoato de emamectina, Dimetoato, entre otros; determinan una acción curativa rápida y confiable cuando el nivel de incidencia supera el umbral de daño económico. La aplicación de insumos a base de Etoprofos (0-etil-S-S-dipropilfosforoditioato) en la etapa de siembra redujo las poblaciones iniciales de Criconemella sp, Pratylenchus sp y Globodera spp en un 78%, 25% y 86% respectivamente. El combate de los problemas fitosanitarios corresponde a un 15% del costo total productivo del cultivo de la papa.
Estimación del costo de producción de un kilogramo de leche y sus variables más influyentes
Authors: Calvo Hernández Olga María
Published: September 2021

El objetivo de esta investigación fue cuantificar el costo de producción de un kilogramo de leche y sus variables más influyentes, a través del sistema de costeo ABC (Activity Based Costing) para la Estación Experimental Alfredo Volio Mata de la Universidad de Costa Rica, para el periodo 2019-2020. La estimación de un costo de producción es una herramienta fundamental para la toma de decisiones dentro de una unidad productiva. Conocer sus componentes y variables más influyentes, permite evaluar cada elemento de forma individual, con lo que se permite realizar un análisis y abordaje más focalizado de cada una de las partes que lo integran y su influencia sobre el costo total. Para ello, se utilizó un sistema de acumulación de costos ABC, en el cual se definieron e identificaron las actividades principales y subactividades, así como las necesidades de materiales, insumos, mano de obra, entre otros. A partir de lo anterior, se obtuvo un costo de producción de ₡713,04 ($1,16) por kilogramo de leche. Que se caracteriza, por ser altamente influenciado por la alimentación (46,52%), mano de obra (23,38%) y materiales de lechería (8,97%); y en menor proporción (menores a un 10%) por variables como mantenimiento de potreros, enfermedades eventuales, materiales de limpieza, agua, electricidad y manejo reproductivo. El costo obtenido en la Estación es un reflejo propio de su manejo productivo y del fin investigativo y no lucrativo, de esta unidad de producción.
PRINCIPLES OF TREATMENT OF PATIENTS WITH PATHOLOGICAL CHANGES IN THE ORAL MUCOSA, TAKING INTO ACCOUNT THE IMMUNOLOGICAL STATUS
Authors: Svechnikova M. V , Selezneva I. A , Postnikov M. A
Published: September 2021

The article presents data from our own research on the relationship of local oral fluid immunity in patients with acute leukemia and ulcerative-necrotic lesions of the oral mucosa after chemotherapy treatment. The state of the oral mucosa is described, and the role of the immunoassay method is indicated. The principles of local treatment of this category of patients are proposed.
Demographics of the Modern World: Comments on Theories
Authors: Ivanov Sergey
Published: September 2021

The article is devoted to the consideration of the key causes and factors of changing trends in the demographic development of the countries of the North and South in the context of fundamental demographic theories. The mechanisms of adjustment of reproductive behavior and their impact on the dynamics of fertility in the regions of the world are analyzed. The features of the demographic transition in the countries of Africa, Asia and Latin America are considered, as well as the author’s forecasts about the likely dynamics of the population in these regions are given. In sub-Saharan Africa, rapid population growth continues and will continue at least until the end of the century. If the trajectory of fertility in Africa repeats its decline in other regions of the world, then by the end of the century the average total fertility rate will fall to the level of simple reproduction there, and the population will grow from the current 1 billion to 2.1 billion people in the middle of the century and 3.8 billion people at the end of the century. The critical analysis of the first and second theories of demographic transition in the conditions of modern society and specific national characteristics of the countries of the world is carried out. The conclusion provides a theoretical and practical analysis of family and demographic policies, as well as their prospects in modern conditions.