bluuebunny/crossref_metadata_2025_split huggingface dataset:
The character of high-frequency strong ground motion
Authors: Hanks Thomas C. , McGuire Robin K. 
Published: June 2021

AbstractAnalysis of more than 300 horizontal components of ground acceleration written by the San Fernando earthquake, eight other moderate-to-large California earthquakes, and seven Oroville aftershocks reveal that these acceleration time histories are, to a very good approximation, band-limited white Gaussian noise within the S-wave arrival window; the band limitation is defined by the spectral corner frequency f0 and fmax, the highest frequency passed by the accelerograph or the Earth's attenuation, and the S-wave arrival window is (0 ≦ t − R/β ≦ Td), where R is distance, β is shear-wave velocity, and Td is the faulting duration. An examination of the root-mean-square acceleration (arms) characteristics of these records for 0 ≦ t − R/β ≦ Td in terms of the relationa rms = 0.85 ( 2 π ) 106 2 Δ σ ϕ R f max f owhere Δσ is the earthquake stress drop, yields the surprising result that all 16 earthquakes have stress drops, as determined by record values of arms, very nearly equal to 100 bars (within a factor of 2). The source dependence of arms thus depends solely on the parameter 1/fo, which increases only as the one-sixth power of seismic moment for constant stress drop earthquakes. Put another way, model and record arms are in agreement within a factor of 2 approximately 85 per cent of the time for Δσ = 100 bars and knowledge of 1/fo.On the basis that acceleration time histories are finite-duration, band-limited, white Gaussian noise, for any of which arms is fixed by Δσ = 100 bars and 1/fo, we can estimate the peak accelerations (amax) for all of these records with considerable accuracy (50 per cent or less). The relation isa max = a rms 2 In ( 2 f max f o ) ,where arms is defined above. With less accuracy, this relation fits the peak acceleration set of Hanks and Johnson (1976) as well, again with Δσ = 100 bars. At a fixed, close distance, we determine the magnitude dependence of amax to be log amax ∝ 0.30 M for 4≲M=ML≲612, close to that recently determined empirically by Joyner and Boore (1981) for 5.0 ≦ M ≦ 7.7, their coefficient on M (moment magnitude) being 0.25 ± 0.04. In the model presented here, the magnitude dependence of peak acceleration is a function of faulting duration alone; larger earthquakes have larger peak accelerations because they last longer, not because they are intrinsically more powerful at the high frequencies controlling peak acceleration.These well-behaved characteristics of high-frequency strong ground motion also suggest that the stress differences which develop in the course of crustal faulting are comparably well behaved, both in the average stress release across the characteristic source dimension and in the spectral composition and distribution of stress differences that develop across smaller dimensions.
Response of structures to nonvertically incident seismic waves
Authors: Luco J. E. , Wong H. L. 
Published: June 2021

abstractA study of the earthquake response of symmetric elastic structures subjected to SH-wave excitation with different angles of incidence and to Rayleigh waves is presented. For SH-wave excitation, particular emphasis is given to the study of the possible reduction of the response due to filtering by the foundation and the torsional response. For Rayleigh wave excitation, the effects of the additional rocking associated with the vertical component of the excitation are investigated. The results obtained for models of a 10-story reinforced concrete building and the containment structure of a nuclear power plant reveal that the response for nonvertically incident waves is significantly different from that obtained on the basis of the usual assumption of vertically incident SH waves.
ASP: An Automated Seismic Processor for microearthquake networks
Authors: McEvilly T. V. , Majer E. L. 
Published: June 2021

abstractASP, a low-power, in-field Automated Seismic Processor of microearthquake network data has been designed, fabricated, and deployed for initial operation in four different field areas to monitor seismicity associated with two geothermal areas (The Geysers, California, and Cerro Prieto, Mexico), a nuclear explosion with its related collapse and aftershock sequence, and late (&gt;1 year) activity in a major aftershock series (Livermore, California). A second ASP system, with a high-speed front-end, is used in acoustic emission (1 to 20 kHz) analysis for fracture monitoring. Each of the 15 channels of ASP (configured for up to 128 channels) automatically detects, measures times and amplitudes, and computes and fits FFT's for both the P and S waves on data sampled at 100 samples/sec. These data from each channel are then processed with a central microprocessor for hypocenter location, running b values, source parameters, event count, and P-wave polarities. The system is capable of processing a 15-station detection in approximately 40 sec, excluding printout. The initial trials have demonstrated that in-field real-time analysis of data maximizes the efficiency of microearthquake surveys allowing flexibility in experimental procedures, with a minimum of the traditional labor-intensive postprocessing. Current efforts are directed toward improving efficiency of computation and data output and in expanding software capabilities.
MLmeasurements for northeastern United States earthquakes
Authors: Ebel John E. 
Published: June 2021

abstractLocal magnitudes (ML) are reported for 56 northeastern United States and Canadian earthquakes using records from a pair of Wood-Anderson torsion instruments which have operated at Weston Observatory since 1967. Corrections to the Richter ML formula are computed to take into account the difference in attenuation between southern California and the northeastern United States. The corrected ML values for these events were compared to the previously reported magnitudes which had been calculated either from the Nuttli (1973) mbLg formula applied to 5- to 10-Hz waves (called MN) or from a coda magnitude formula (Mc). In general, the ML determinations tend to underestimate the MN and Mc values by about 0.4 magnitude units. This confirms the fact that the MN scale is not appropriate when applied to high-frequency waves, as it is in the northeastern United States. The reason for this appears to be in the relation of the period of the wave used in the magnitude determination to the corner period of the earthquake and earth response.
Shallow-focus seismicity, composite focal mechanism, and tectonics of the Valle Central of Costa Rica
Authors: Montero P. Walter , Dewey James W. 
Published: June 2021

abstractA network of seismographs operating in the Valle Central of Costa Rica has recorded many small earthquakes near the cities of Cartago and San Jose. This seismicity is similar in many ways to the shallow-focus intraplate seismicity of Central America to the north. The earthquakes occur within tens of kilometers of Quaternary volcanic centers at shallow focal depths. The earthquakes occur predominantly on strike-slip faults, with the nodal plane that would correspond to a left-lateral fault striking approximately east-northeast and the nodal plane that would correspond to a right-lateral fault striking approximately north-northwest. The shocks have a tendency to occur in seismic swarms.The region of highest seismicity in our study was located southwest of Cartago, about 10 km from the meizoseismal zones of destructive earthquakes of 1841 and 1910. In detail, the recently recorded small earthquakes seem to have occurred on different faults or fault segments than the 1910 earthquakes. The tendency for shallow-focus intraplate earthquakes to occur within kilometers of earthquakes that occurred several decades earlier has been noted elsewhere in Central America. The occurrence of shocks on distinct faults within the overall region of high activity appears similar to the occurrence of earthquakes on different fault strands in Managua, Nicaragua. We discuss the Valle Central seismicity in light of hypotheses proposed for the shocks farther north in Central America. Our data can be interpreted in terms of the hypothesis that shallow-focus intraplate earthquakes in Central America concentrate on zones of strike-slip faults that pass through offsets of the volcanic chain. Our data can also be interpreted in terms of the hypothesis that the earthquakes occur as the response of minor faults to high regional stresses throughout the region surrounding the volcanic chain. Both hypotheses leave some characteristics of the seismicity unexplained, although these characteristics are not crucial evidence against the hypotheses. A third hypothesis, that the Valle Central source regions are different than intraplate source regions northward in Central America and are occurring in a developing transform plate boundary between the Caribbean and Nazca plates, is plausible on the basis of the regional plate tectonic environment, but it is not strongly supported by the local geology of the Valle Central or by the characteristics of seismicity.
Strain, tilt, and rotation associated with strong ground motion in the vicinity of earthquake faults
Authors: Bouchon Michel , Aki Keiiti 
Published: June 2021

abstractIn the absence of near-field records of differential ground motion induced by earthquakes, we simulate the time histories of strain, tilt, and rotation in the vicinity of earthquake faults embedded in layered media. We consider the case of both strike-slip and dip-slip fault models and study the effect of different crustal structures. The maximum rotational motion produced by a buried 30-km-long strike-slip fault with slip of 1 m is of the order of 3 × 10−4 rad while the corresponding rotational velocity is about 1.5 × 10−3 rad/sec. A simulation of the San Fernando earthquake yields maximum longitudinal strain and tilt a few kilometers from the fault of the order of 8 × 10−4 and 7 × 10−4 rad. These values being small compared to the amplitude of ground displacement, the results suggest that most of the damage occurring in earthquakes is caused by translation motions. We also show that strain and tilt are closely related to ground velocity and that the phase velocities associated with strong ground motions are controlled by the rupture velocity and the basement rock shearwave velocity.
Source dynamics of the 1979 Imperial Valley earthquake from near-source observations (of ground acceleration and velocity)
Authors: Niazi Mansour 
Published: June 2021

abstractTwo sets of observations obtained during the 15 October 1979 Imperial Valley earthquake, MS 6.9, are presented. The data suggest different dynamic characteristics of the source when viewed in different frequency bands. The first data set consists of the observed residuals of the horizontal peak ground accelerations and particle velocity from predicted values within 50 km of the fault surface. The residuals are calculated from a nonlinear regression analysis of the data (Campbell, 1981) to the following empirical relationships, PGA = A 1 ( R + C 1 ) − d 1 , PGV = A 2 ( R + C 2 ) − d 2 in which R is the closest distance to the plane of rupture.The so-calculated residuals are correlated with a positive scalar factor signifying the focusing potential at each observation point. The focusing potential is determined on the basis of the geometrical relation of the station relative to the rupture front on the fault plane.The second data set consists of the acceleration directions derived from the windowed-time histories of the horizontal ground acceleration across the El Centro Differential Array (ECDA). The horizontal peak velocity residuals and the low-pass particle acceleration directions across ECDA require the fault rupture to propagate northwestward. The horizontal peak ground acceleration residuals and the high-frequency particle acceleration directions, however, are either inconclusive or suggest an opposite direction for rupture propagation. The inconsistency can best be explained to have resulted from the incoherence of the high-frequency radiation which contributes most effectively to the registration of PGA.A test for the sensitivity of the correlation procedure to the souce location is conducted by ascribing the observed strong ground shaking to a single asperity located 12 km northwest of the hypocenter. The resulting inconsistency between the peak acceleration and velocity observations in relation to the focusing potential is accentuated. The particle velocity of Delta Station, Mexico, in either case appears abnormally high and disagrees with other observations near the southeastern end of the fault trace. From the observation of a nearly continuous counterclockwise rotation of the plane of P-wave particle motion at ECDA, the average rupture velocity during the first several seconds of source activation is estimated to be 2.0 to 3.0 km/sec. A 3 km upper bound estimate of barrier dimensions is tentatively made on the basis of the observed quasiperiodic variation of the polarization angles.
Deformations associated with the El Asnam earthquake of 10 October 1980: Geodetic determination of vertical and horizontal movements
Authors: Ruegg J. C. , Kasser M. , Tarantola A. , Lepine J. C. , Chouikrat B. 
Published: June 2021

abstractThe resurvey of both a geodetic network and a leveling net was carried out in June 1981 8 months after the MS = 7.3 El Asnam earthquake of 10 October 1980. Previous seismological and neotectonic studies (Ouyed et al., 1981; Yielding et al., 1981) indicate that this event results from a northeast-trending overthrust complex fault of about 40-km length, which shows at least three principal segments with slightly different directions. Vertical movements, evaluated by means of a trigonometric leveling method, show an uplift of the northwestern side of the thrust fault of about 5 m and a depression of the southeastern edge of about 1 m. These movements are progressively attenuated away from the fault trace. Horizontal movements have been evaluated by a classical first-order triangulation method. The resulting mean strain tensors, calculated for different triangles of the geodetic network, indicate a shortening of about 2.50 m which is consistent with the SE-NW direction of compression determined from neotectonic evaluations and focal mechanisms. Dislocation models are used to explain and discuss the observed deformations in light of the seismological data and observed ground breakages. Five segments are required to explain both horizontal and vertical deformations. The magnitude of vertical displacements (about 6 m) at the junction between the southwest and the central segments of the fault argues for the breaking of this area during the main shock and for a slip vector of about 8 m, at least in the central segment.
Eyestrain and associated problems among undergraduate medical students undergoing e-learning/teaching methods during Covid-19 pandemic
Authors: Anthrayose C V , Joju Aqueen , Puthiyedath Rakendu , Babu Niya , Rajan Ann Reshma 
Published: June 2021

Increase in usage of digital devices and mandatory e-learning imposed during the Covid 19 pandemic curfew may have given rise to an emerging public health threat of digital eyestrain among undergraduate medical students in the state. The study aimed to assess the distribution of digital eyestrain among undergraduate medical students and to determine the association between digital eyestrain and screen time spent on different digital devices for e-learning and social media use.A cross sectional, questionnaire based online study was done on undergraduate medical students of a teaching hospital in Central Kerala during the month of October, 2020. Survey form included CVS-Q questionnaire, OSDI questionnaire and questions regarding screen time spent on different digital devices for e-learning and social media use.Around three -fourth of the 113 participants experienced at least one symptom of digital eyestrain. Headache (76.1%) was the most common symptom followed by neck/shoulder/back pain (67.3%), tearing(49.6%), itching(48.7%), eye pain (41.6%) and increased sensitivity to light (38.1%).OSDI score revealed that 67.7% of the students had dry eye disease. Screen time of more than 6 hours spent on mobile/tablet was significantly associated with feeling of foreign body sensation, excessive blinking and itching. Lens /spectacle use was significantly associated with a feeling that eyesight is worsening and difficulty focusing for near vision. No association was seen between screen time spent for e- learning and digital eyestrain. Steps towards awareness and prevention of digital eyestrain should be taken to promote ocular health and to avoid this occupational hazard.
Association of HbA1c levels with diabetic retinopathy
Authors: Singh Chirag , Prasad Shashi Prabha , Kaul Sucheta , Motwani Divya , Mishra Ashish , Padmakumar Vishakh 
Published: June 2021

To study the association of HbA1C levels with diabetic retinopathy.A total of 330 diagnosed diabetic subjects of all age groups and genders participated in the study. They were grouped according to presence or absence of diabetic retinopathy. All patients HbA1C levels along with fasting blood glucose levels was obtained. Observations were made to find the association between HbA1C levels and diabetic retinopathy.Mean HbA1c level among diabetic retinopathy subjects (9.50) was higher than subjects without retinopathy (8.49). The difference was found to be statistically significant (p &#60; 0.05). With high HbA1c levels high mean fasting blood glucose levels were associated (R value: 0.5856). This is a moderate positive correlation.As glycosylated haemoglobin (HbA1c) levels increases prevalence of diabetic retinopathy also increases and there is a strong relationship between HbA1c levels and diabetic retinopathy.
Islam-based peace education: values, program, reflection and implication
Authors: Santoso M Abdul Fattah , Khisbiyah Yayah 
Published: June 2021

There is a gap between ideal Islam and real Islam. Ideal Islam means peace, greeting, safety, salvation, and conceptually means absolute submission to God`s Will. Real Islam resembles unresolved conflicts in some communities and unpleasant meanings to some non-Muslims. To minimize the gap, it is important to socialize peaceful Islamic values in the community through education. This study aims to explain Pendidikan Perdamaian Berbasis Islam (PPBI, the Islam-based Peace Education) program initiated by Pusat Studi Budaya dan Perubahan Sosial (PSB-PS, the Center for the Study of Culture and Social Change) at Universitas Muhammadiyah Surakarta (UMS). This participatory action research is especially to reveal Islamic values identified in the PPBI program in terms of its uniqueness, implementation, reflection, and implication. Based on the Sirah of the Prophet and the Al-Qur’an, the PPBI program has identified 15 Islamic values which contribute to peacebuilding. Those values were used as core contents of PPBI’s handbook and classroom program. The program has been implemented through series of activities ranging from seminars, FGDs, workshops, training of teachers, publication of books, and classroom implementation. PPBI program based on nonviolence and peacebuilding assumptions, i.e. to build a culture of peace, is designed as the formal peace education through learning materials and classroom processes either in any existing course or co-curricular activities.
Personal Mastery and All-Cause Mortality among Older Americans Living with Diabetes
Authors: Tung Ho-Jui , Yeh Ming-Chin , Ford Randall , Shah Gulzar 
Published: June 2021

Introduction: Higher personal mastery is associated with better physical functioning, wellbeing, and longevity among older populations. However, few studies have focused on whether personal mastery is protective against mortality among older adults living with diabetes over time.
Methods: A total of 1,779 participants were identified from an off-year survey of the Health and Retirement Study. Proportional Hazard Models were used to evaluate the significance of selected variables in predicting the survival of participants over a 13-year period.
Results: A substantial proportion (46.7%) of the diabetic patients had survived by the end of 2016. Adults with lower mastery scores were more likely to die (Hazard Ratio = .94, p < .001). Gender differences in the association patterns between personal mastery and survival were identified. Personal mastery had an independent health-protective effect on the survival of diabetes patients over the study period. With lower educational attainment, the foreign-born female diabetics scored higher in personal mastery measure when compared to their male counterparts. In the face of more severe diabetes comorbidity, foreign-born female diabetics also outlived their male counterparts over the study period.
Conclusion: As a crucial psychological resource and a modifiable factor, personal mastery holds a potential for improving the health status among lower SES groups of older adults. Further investigations into the identified gender difference could be applied to break the cycle of poor health among lower Socio-Economic Status groups of older adults.
In Vitro Activity of Disinfectants against Mold Fungi Isolated from Different Environments of the Children’s Medical Center Hospital, Tehran, Iran
Authors: Karimpour Roshan Sedighe , Godini Hatam , Ansari Saham , Charsizadeh Arezoo , Norouzi Maryam 
Published: June 2021

Introduction: Fungal aerosols cause life-threatening infections in patients hospitalized in critical wards. Antiseptics and disinfectants have broad-spectrum antimicrobial activity against the living tissue and inert surfaces microorganisms; hence, they have an essential role in controlling and preventing nosocomial infections. This study aimed to evaluate in vitro antifungal activity of benzalkonium chloride (BAC), chlorhexidine digluconate (CHX), and sodium hypochlorite (SH) against isolated fungal aerosols from the hospital environment.
Materials and Methods: The susceptibility tests were performed on fungal aerosols isolated from various wards of Children’s Medical Center, based on broth microdilution antifungal susceptibility testing of filamentous fungi approved by the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. The isolates included Aspergillus (Aspergillus flavus (n = 14), Aspergillus niger complex (n = 12), Penicillium spp. (n = 14), and Cladosporium spp. (n = 14).
Results: The geometric means (GM) of the Minimum Inhibitory Concentrations (MICs) of the biocides across all isolates were as follows: BAC, 3.56 µg/ml, CHX, 9.45 µg/ml, and SH, 810.35 µg/ml. The highest range of MICs was found for SH (50-12800 µg/ml), while the lowest range was for BAC (1-16 µg/ml) against all fungal isolates. Generally, BAC showed the highest in vitro activity among disinfectants tested. The lowest MIC50 and MIC90 values were 4 and 8 µg/ml for BAC, followed by 16 and 32 µg/ml for CHX, and 800 and 6400 µg/ml for SH, respectively.
Conclusion: The findings showed that BAC was an effective disinfectant, which can prevent resistant species and fungal pathogens and be used an alternative to other disinfectants and antiseptics.