bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Leishmania infantum amastigotes in neutrophil from peripheral blood in a naturally infected dog
Authors: Oliveira Gilsan Aparecida de , Sarmento Vitória Aline Santos , Costa Ericka Wanessa da Silva , Pessoa-e-Silva Rômulo , Morais Rayana Carla Silva de , Ferreira Roberto Rômulo , Feitosa Ana Paula Sampaio , Brayner Fábio André , Alves Luiz Carlos
Published: July 2021

Abstract Canine visceral leishmaniasis (CVL) is a zoonotic disease of high lethality caused by Leishmania infantum in the Americas. In the infected dog, the amastigotes are scarce in blood, especially in the late phase of the disease. This study aimed to report a rare case of L. infantum amastigotes found in neutrophils from peripheral blood of a naturally infected dog in terminal phase of CVL, also describing its clinical status before and after treatment with miltefosine 2%. The dog, which presented as polysymptomatic and with classical signs and symptoms of CVL was submitted to the following tests: Dual Path Platform (DPP) rapid test, ELISA and parasitological examination of peripheral blood. Hematological and biochemical parameters were obtained before and after treatment. All diagnostic tests were positive for CVL. The identification of L. infantum amastigotes inside neutrophils from peripheral blood was confirmed through microscopy, and the species was confirmed by molecular analysis. At the end of the treatment, peripheral parasitemia was not detected, and improvements were observed in clinical and laboratorial parameters. Finally, this atypical finding can be used as example to raise discussions about the real immunological role of neutrophils in late phases of CVL and its clinical/therapeutic implications.
Entre idéal d’égalité et constat d’iniquité: démêler l’écheveau conceptuel des relations entre handicap et inégalité
Authors: Debeaudrap Pierre , De Loenzien Myriam , Beninguisse Gervais
Published: July 2021

Inégalité et handicap sont deux notions si étroitement liées l’une à l’autre que leur mise en relation nécessite paradoxalement un effort conceptuel qui à la fois les distingue et clarifie leurs liens. Dans le domaine des études de population, ce besoin se double de la nécessité d’opérationnaliser les concepts. Le handicap a progressivement été défini comme un processus socialement construit, ouvrant la voie à une analyse des inégalités et particulièrement des situations d’iniquité. Des relations de causalité réciproques entre handicap et inégalité ont été explorées, accordant une place centrale à la notion de participation sociale. Celle-ci se heurte à la variabilité de sa définition. Plusieurs modèles ont mis en évidence des mécanismes sociaux sous-jacents à ces relations, proposant de nouvelles perspectives comme l’a fait l’approche des capabilités. Ces réflexions toujours en cours témoignent du dynamisme de ce champ de recherche novateur que constituent les « disability studies ». Celui-ci, porteur d’un idéal d’égalité, jette une lumière spécifique sur la notion d’inégalité.
FEATURES OF THE STRAIN-STRESS STATE OF BEAMS WITH A CORRUGATED WALL OF VARIABLE RIGIDITY
Authors: MOLEVA Natalia Yu.
Published: July 2021

Corrugated steel beams represent a promising area of research in the fi eld of structural engineering today. The article studies the behavior of a metal beam with a corrugated wall of an I-profi le under bending conditions. Beam considered span of 12 m. A fi nite element model of the calculated structure was built in the LIRA-SAPR software package. The analysis of the stress-strain state of a corrugated beam of variable stiff ness, which has a fl at fragment in the central part of the wall, is carried out. The beam thus obtained has a number of advantages over beams with only a fl at or fully corrugated wall. The conclusions based on the results of the analysis of the calculation are presented.
LOCAL STUDIES OF ICE COVER EFFECTS ON DAM GATES
Authors: EVDOKIMOV Sergey V. , ROMANOV Alexey A. , IVANOV Boris G.
Published: July 2021

The experience of operation of surface emergency gates in ice-breaking conditions at a number of hydroelectric power plants has shown the insuffi cient eff ectiveness of the methods used to combat freezing of structures. The rules for technical operation of spillway dam gates in winter provide for heating of structures by slots, threshold and skin in conjunction with measures to maintain mines before construction. However, measures to heat gates and build mines are not always suffi ciently justifi ed and justifi ed. In order to obtain full-scale data and scientifi c information for the development of recommendations on operating and accounting modes during design, full-scale studies of stresses and defl ections in the load-bearing elements of the watershed gate of the hydroelectric power station were carried out. This article presents the results of fi eld studies in comparison with calculated values. As a result of the studies, information on the static operation of fl at gates in winter conditions is obtained, which is of theoretical and practical interest. The materials can be used to clarify technical operation rules and to clarify regulatory documents for the design of hydromechanical equipment at hydroelectric power stations.
ANALYSIS OF ORGANIZATIONAL AND TECHNOLOGICAL SOLUTIONS ON THE CHOICE OF THE CRANE WHEN DESIGNING BUILD PLANS IN CONSTRUCTION SITE CONDITIONS
Authors: ZORINA Marina A. , RYAZANOVA Galina N. , ILDIYAROV Evgenij V.
Published: July 2021

The principles of determining the conditions of tightness of the construction site in accordance with the requirements of normative documentation are shown. On concrete examples the features of defi nition of types of cranes, conditions of their placement on a construction site are considered. Shows examples of the placement of diff erent valves within a single construction site. The possibilities of limiting the boundaries of the zones of operation of the crane are determined. Possibilities of restriction of a dangerous zone of action of the crane according to the standard literature are presented.
THREE-DIMENSIONAL MODELING TECHNOLOGIES IN INDUSTRIAL DESIGN
Authors: RAKOV Anton P.
Published: July 2021

Currently, specialists who use the skills of drawing, drawing, modeling and modeling in their work have largely begun to use the capabilities of computer technology and software. Working with digital models and three-dimensional modeling technologies are also within the competence of an industrial designer. This article att empts to make a selection of computer programs that are used in their work by industrial designers and classify the capabilities of this software according to its functional purpose. It is obvious that all the technologies of three-dimensional modeling listed in the article are very important for specialists engaged in technical aesthetics, artistic design, visualization, prototyping and prototyping of things.
HYDRODYNAMIC CALCULATION OF CONTACTLESS SEALS WITH PLANE SLOTS IN DRIVES OF ELECTRIC POWER SYSTEMS
Authors: KRESTIN Evgeny A. , SEREBRYAKOV Grigoriy V.
Published: July 2021

Non-contact seals with fl at slott ed gaps of drives of electric power systems used in switchgears of hydraulic units, as well as in pumps and hydraulic motors have been investigated. Calculation of seals based on average clearance results in an underestimation or overestimation of the leakage rate compared to the operational values. The regularity of the distribution of pressure and fl ow rate in the gap of a fl at conical slot is determined, and formulas for the fl ow rate (leakage) and friction forces acting on the walls of the conical slot are found. To solve the problem, the approximate Navier-Stokes and fl ow continuity equations are used. Several special cases of the fl ow of the working fl uid in diff erent gaps are considered: a plane-parallel gap with an oscillating wall and at a constant pressure gradient and a conical gap at diff erent ratios of the pressure drop and the frictional action of the moving channel wall. When the wall oscillates in a conical gap and constant pressure, the presence of an extremum is characteristic. In this case, an excess pressure appeared in the slott ed gap, creating a supporting force, and the pressure value became high enough. When the lower wall of the conical slot moves in the direction of the increasing gap, the pressure inside the slott ed channel, under certain conditions, can reach a complete vacuum, the value of which is limited by the bulk strength of the liquid and the pressure of saturated vapor at a given temperature. When the pressure drop and oscillations of the wall of the conical gap are additive, then at a suffi ciently high velocity of the wall movement, the pressure inside the slot can even increase and exceed the value of the supplied pressure.
The program of psychological rehabilitation of persons with acquired disorders of the musculoskeletal system
Authors: Razuvaeva Tatyana N. , Lokteva Anna V. , Gut Julia N. , Pchelkina Eugenia P.
Published: July 2021

The study of factors influencing the success of rehabilitation of persons with acquired musculoskeletal disorders acquired in adulthood is determined by the increasing role in the psychological support and integration of such individuals into society, as well as the lack of methodological approaches and proven recommendations aimed at improving the rehabilitation process. The paper presents the psychological characteristics of people with musculoskeletal disorders acquired in adulthood. According to the results of psychodiagnostic examination, the program of psychological support for persons with musculoskeletal disorders has been developed. The aim of the study was to study the psychological characteristics of persons with acquired disorders of musculoskeletal disorders, to develop and evaluate the effectiveness of the program of psychological rehabilitation. We used the following research methods: clinical and psychological, psychodiagnostic, statistical, methods of analysis of empirical data. The ascertaining study was carried out with two groups: with disorders of the musculoskeletal disorders and without violations of the musculoskeletal disorders (the total number of participants was 60 people). Diagnostic tools: questionnaire Adaptability (A.G. Maklakov, S.V. Chermyanin), Freiburg personality questionnaire (modified by A.A. Krylov, T.I. Ronginskaya), Style of self-regulation of behavior (V.I. Morosanov), Test of resilience (S. Maddy, adaptation by DA Leontiev). Statistical data processing was carried out using the following criteria: Mann-Whitney U-test, Wilcoxon T-test using SPSS Statistics 19. It was revealed that persons with acquired disorders of musculoskeletal disorders are characterized by low adaptive abilities, an increased level of neuropsychic stress. Characterized by an insufficient level of self-regulation, the ability to consciously plan activities. It is determined that resilience is characterized by low involvement, insufficient ability to overcome life difficulties. It is shown that a personal factor that enhances maladjustment is low contact, emotional tension when interacting with others. The proposed program of psychological assistance to persons with disorders of the musculoskeletal system helps to overcome passivity, alienation; the formation of independence, responsibility, an active life position, a system of value orientations, strengthening of social position, and, ultimately, successful social adaptation.
Organizational and pedagogical conditions of formation of teacher’s professional image in the context of education standartization
Authors: Sharueva Ekaterina V.
Published: July 2021

In the structure of modern standards of education, one of the important and popular components that increases the effectiveness of pedagogical activity is the professional image of the teacher. The importance of teachers professional image formation is actualized as this image promotes not only productivity, but also influences the perception of the teaching work representative by participants of the educational process. In the process of teachers professional image formation organizational and pedagogical conditions should be provided considering the context of standardization of education. The concept of the conditions in question is defined. The analysis of theoretical research of pedagogical conditions of teachers professional image formation is based on the requirements to pedagogical activity of Federal state educational standards and the professional standard Teacher, which allowed to determine current organizational and pedagogical conditions of the teachers professional image formation in terms of standardization of education. The objective organizational conditions for teachers professional image formation are the following: standardization of the education process, creation of a polysubject educational environment, teachers motivation formation for professional and image development, the development of professional and image competence of teachers, the development of image self-reflection in the professional activities of teachers.
Wellness Decolonized: The History of Wellness and Recommendations for the Counseling Field
Authors: Gamby Katie , Burns Dominique , Forristal Kaitlyn
Published: July 2021

The word wellness became mainstream in the United States around 1980, and wellness counseling literature often cites the beginnings of wellness around this time. The problem with this identification is that the roots of what counselors understand the wellness movement to be stretch back to between 3,000 and 1,500 BCE in India. Since wellness counseling literature often is not contextualized appropriately, failing to address the historical roots of wellness concepts and practices earlier than the 1980s wellness movement in the West, counselors are often missing crucial information regarding wellness for themselves and their clients. The purpose of this article is to encourage social change by grounding the wellness counseling literature in this missing history. To do this, we explore wellness from its conception until the present day, discuss wellness practices for historically marginalized groups (i.e., Black, Indigenous People, queer, fat, and disabled people), and provide implications for mental health counselors.
MERHAMET DOYUMU ÖLÇEĞİNİN GELİŞTİRİLMESİ
Authors: Nas Eşref , Sak Ramazan
Published: July 2021

Merhamet doyumu kişinin merhametli eylemlerde bulunmaktan dolayı elde ettiği memnuniyet halidir. Bu çalışmanın amacı yetişkinlerin merhamet doyumlarını belirlemeye yönelik Merhamet Doyumu ölçeğinin geliştirilmesidir. Ölçeğin psikometrik özelliklerinin belirlenebilmesi için 504 yetişkinden veri toplanmıştır. Yapılan açımlayıcı faktör analizi sonucunda 12 madde tek bir faktör altında toplanmış ve bu tek faktörlü yapı toplam varyansın %56,14’ünü açıklamıştır. Elde edilen bu tek faktörlü yapı doğrulayıcı faktör analizi ile test edilmiş ve elde edilen uyum değerlerinin (2/sd= 2.563; RMSEA=.079, RMR=.027, IFI=.95, CFI=0.96, NFI=.92, RFI=.90, GFI=.92, AGFI=.88) iyi uyum gösterdikleri bulunmuştur. Merhamet Doyumu ölçeğinin iç tutarlılık katsayısı .92 ve yarı güvenirlik katsayısı ise .90 olarak bulunmuştur. Sonuç olarak, yetişkinlerin merhamet doyumu düzeylerini belirlemeye yönelik geliştirilen Merhamet Doyumu Ölçeğinin geçerli ve güvenilir bir ölçme aracı olduğu saptanmıştır.
Fingertip defects coverage using reverse-flow homodigital island flaps
Authors: Alexandrov Alexander V. , Smirnov Alexander A. , Gonchruk Pavel V.
Published: July 2021

BACKGROUND: The hand has always been a highly organized tool in humans daily and professional activity. Distal phalanges are most commonly exposed to trauma, which often cause defects that need to be covered through plastic surgery. One of the most reliable and universal methods for fingertip reconstruction is the reverse-flow homodigital island flap.
CLINICAL CASES: This series of clinical cases describe three children aged 7, 8, and 11 years who underwent coverage of fingertip defects with the reverse-flow homodigital island flap. In all cases, mechanisms of injury were associated with crushing and rupture of soft tissues. All children underwent coverage of fingertip defects with the reverse-flow homodigital island flap. In the first case, evaluation results at 6 months after surgery revealed 4 mm in the Webers test and phalanx length deficit of 2 mm. In the second case, the assessment performed 1 month after surgery revealed 5 mm in the Webers test and the length of the operated phalanx corresponds to the contralateral one. In the third case, results of the 2-month observation period revealed 4 mm in the Webers test and lengths of the operated and contralateral phalanges were the same.
DISCUSSION: The reverse-flow homodigital island flaps have irrefragable advantages among methods of surgical reconstruction of soft tissues of distal phalanges. These are single-stage reconstruction techniques that can possibly replenish sufficient amounts of soft tissues to the defect. A literature data analysis of the outcomes of the fingertip reconstruction through the reverse-flow homodigital island flaps revealed good and satisfactory results.
CONCLUSIONS: The method of the reverse-flow homodigital island flap has potential to take a significant place in pediatric traumatology and reconstructive surgery.
Comparative analysis of the quality of life of children with congenital scoliosis after surgical treatment: Extirpation of the hemivertebra from dorsal and combined access
Authors: Kokushin Dmitry N. , Khardikov Michael A. , Vissarionov Sergey V. , Sokolova Vera V. , Khusainov Nikita O. , Zaletina Anna V.
Published: July 2021

BACKGROUND: Congenital scoliosis with disorders of the formation of the vertebrae is the most common cause of pronounced deformities of the spine in early childhood. This pathology can be treated surgically using various techniques that differ in invasiveness, severity of the condition in the postoperative period, achieved result of deformity correction, and nature of the long-term prognosis. Numerous studies have assessed the quality of life of patients who underwent surgery for acquired deformities, trauma, and degenerative and neoplastic diseases of the spine in adults. However, features of the childs quality of life following surgical technique for congenital scoliosis have not been sufficiently studied.
AIM: This study aimed to compare the quality of life of children with congenital scoliosis of the thoracolumbar localization after extirpation of the hemivertebra from the dorsal and combined approaches.
MATERIALS AND METHODS: An intergroup prospective analysis of the results of a survey of 60 patients with congenital deformity of the spine against the background of an isolated violation of the formation of the thoracic or lumbar vertebra was carried out. Patients underwent standard surgical treatment. Patients were divided into two groups according to the surgical approach to the abnormal vertebral body: dorsal group (n = 28) and combined group (n = 32). The average age of the patients was 75 (minmax, 26196) months. The follow-up period was 18 months after surgery. To assess the quality of life, a specialized Russian version of the PedsQL v4.0 questionnaire and a modified visual analog scale were used.
RESULTS: After surgical treatment of congenital spinal deformity, quality of life indicators decreased more than two times than the results of a preoperative survey. At 18 months postoperatively, the physical activity and psychoemotional state were restored to the preoperative level, while patients of the combined group had a higher satisfaction score on the quality of life (p 0.05).
CONCLUSIONS: The combined approach provides the best correction of congenital deformity of the spine and allows maintaining of the achieved result throughout the observation period. In the early postoperative period, the combined group demonstrated a significant decrease in the level of satisfaction with the quality of life, while the pain syndrome was higher than that in the dorsal group. Dynamic observation revealed the leveling of these differences and a subsequent increase in the level of satisfaction with the quality of life of these patients.
Standard procedure for the pharmacotherapy of pain in childhood
Authors: Kollerová Adriana
Published: July 2021

Physicians of all specialties encounter patients in pain. The basis of the philosophy of caring children is not to question the existence of pain but to predict, prevent, and adequately treat it. Acute pain services implement preventive and multimodal analgesic treatment to increase the analgesic effect at the lowest possible doses to minimize undesirable effects of individual drugs. However, this service cannot be provided in all hospitals 24 hours a day. This study provides a clear, color-coded recommendation for pain relief in children, which provides a quick, rational, and safe choice of analgesics or their safe and effective combinations and dosage for each age group.
Akut Romatizmal Ateş Hastalığında Görülen Ritim ve İleti Bozuklukları
Authors: GÜVENÇ Osman
Published: July 2021

Akut romatizmal ateş, gelişmekte olan ülkelerde çok sık görülen bir hastalıktır. Morbiditeden ve mortaliteden kalp tutulumu sorumludur. Mitral ve aort kapağında yetmezlik ve darlık, konjestif kalp yetmezliği, miyokardit ve perikardit görülebilir. Hastalığının seyri sırasında kardit gelişmese bile birçok ritim ve ileti kusuru ortaya çıkabilir. Bunlar arasında her dereceden atriyoventriküler blok, sinüs taşikardisi ve bradikardisi, atriyal ve ventriküler erken atımlar, akselere nodal ritim, supraventriküler taşikardi, junctional ve ventriküler taşikardi sayılabilir. Bu derlemede, önemli bir halk sağlığı problemi olmaya devam eden akut romatizmal ateş hastalığında ortaya çıkabilen ritim ve ileti kusurları, literatür bilgileri eşliğinde tartışıldı.
The effect of topography on earthquake ground motion: A review and new results
Authors: Geli Louis , Bard Pierre-Yves , Jullien Béatrice
Published: July 2021

A brief review of experimental and theoretical results about the effect of topography on seismic motion shows that they are consistent only on a qualitative basis. Amplification at mountain tops for wavelengths comparable with mountain widths is predicted and observed, but the numerical simulations often underestimate the actual observed effects. We propose that this disagreement is because current models are not complex enough.

We therefore computed the response to incident SH waves of a set of different complex configurations that include two-dimensional surface topography, with or without periodic ridges and subsurface layering. The results show that: (1) the topographic effect in itself is difficult to isolate from other effects, like surface layering, and therefore the amplification on top of geomorphologically complex sites cannot be predicted by a priori estimations based solely on topography; and (2) the high crest/base amplification ratio observed in the field cannot, usually, be matched even with complex two-dimensional structures with incident plane SH waves, which suggests that more complex models are needed to incorporate more complex wave fields (e.g., SV, surface) and three-dimensional geologic configurations.
Spectral estimates of teleseismicP-wave attenuation to 15 Hz
Authors: Walck Marianne C.
Published: July 2021

NORESS recordings of nuclear explosions in central Asia (Δ = 38°) provide new spectral attenuation estimates for frequencies from about 3 to 15 Hz. Two path spectra, representing propagation losses from the Shagan River and Degelen test sites to southern Norway, are calculated using the double-averaging technique of Bache et al. (1985, 1986). Both paths exhibit less attenuation than previously documented for explosions recorded teleseismically at the UKAEA arrays over the 1- to 8-Hz frequency range. The Shagan and Degelen spectra have somewhat different decay rates, perhaps reflecting variations in average source properties. Since the NORESS data extend to higher frequencies than previously available for attenuation measurements, we compare the NORESS spectral data to published models derived from NORSAR data (1 to 8 Hz) for the same path. The Degelen-NORSAR model is compatible with the NORESS data to about 7 Hz, but from 7 to 15 Hz, it predicts higher spectral amplitudes than are observed Using a hybrid absorption band-constant t* formulation, new models are derived which fit both the Shagan River path spectrum (t0* = 0.6 sec, τm = 0.05 sec, (t1* = 0.07 sec) and the Degelen spectrum (t0* = 0.6 sec, τm = 0.05 sec, (t1* = 0.05 sec) from 3 to 15 Hz. The NORESS data support frequency-dependent t* in the 3- to 15-Hz frequency range. The results also demonstrate that extrapolation of attenuation models obtained from longer period data to shorter periods may not predict the correct spectral levels. Actual high-frequency measurements are needed in order to characterize attenuation behavior at high frequencies.
Spatial and temporal correlation between codaQand seismicity in China
Authors: Jin Anshu , Aki Keiiti
Published: July 2021

A map of coda Q at 1 Hz (Q0) was constructed for China by analyzing more than 1000 seismograms from 80 seismic stations distributed throughout China. The resultant contour map of Q0 shows a strong correlation with the epicenters of historic great earthquakes in China. The high Q0 regions are devoid of the epicenters, and the low Q0 regions are full of them. A remarkably linear relation was found between the logarithm of coda Q0 and the maximum earthquake within the area sampled by coda waves (radius of about 150 km from each station) when we consider earthquakes which occurred from 1700 to present. Roughly speaking, if Q0 is 1000, Mmax is about 4 and if Q0 is 100, Mmax is about 8. This relation will be very useful for siting critical facilities such as nuclear power plants and waste disposal sites.

We also found evidence in support of the migration of low Q0 region coincident with the well-known migration of high seismicity region over the distance of several hundred kilometers during the period of several hundred years. If the migration is due to a diffusion process, the diffusion constant is of the order of 100 km2/yr, which agrees very well with those associated with the aftershock migration, fluid injection, and Vp/Vs anomaly.

Comparison of coda Q0 with Q1 estimated from the intensity data shows that they agree very well for Q1 > 150, supporting the validity of the S to S single backscattering model for coda waves. For Q1 < 150, however, coda Q0 becomes constant independent of Q1. This behavior is qualitatively consistent with numerical experiments of Frankel and Clayton, and suggests that coda Q may be measuring the intrinsic Q of about 150 for these regions where Q1 < 150. This limiting coda Q value may depend on regions because coda Q lower than 100 has been observed in some active regions in this study, and also coda Q as low as 30 to 40 has been reported in California, Mexico, and Italy.
Rupture process of the 1980 Izu-Hanto-Toho-Oki earthquake deduced from strong motion seismograms
Authors: Takeo Minoru
Published: July 2021

The 1980 Izu-Hanto-Toho-Oki earthquake is studied in detail using near-field strong motion seismograms recorded at Japan Meteorological Agency stations. A seismogram inversion method is applied to deduce the dislocation distribution and the character of rupture propagation during this earthquake.

This earthquake involves left-lateral strike-slip motion on the almost vertical plane with a strike of N10°W. The fault plane is shallower than about 12 km in depth, and the length is about 20 km. The large dislocation (large seismic moment) occurs near the hypocenter and at the southern end of the fault plane. The rupture propagates southward from the central part of the fault plane and spreads to the shallow area of the northern part of the fault plane after a delay of about 5 sec relative to the initiation of this earthquake. The total seismic moment is about 7 ×1025 dyne·cm.

The aftershocks of magnitude equal to or greater than 4.0 take place in the areas where high stresses are expected to remain after this earthquake. The mechanical weakness of small submarine monogenetic volcanoes which are located above the source region seems to affect the rupture process of this earthquake.
Source properties of two microearthquakes at Kilauea Volcano, Hawaii
Authors: Li Yingping , Thurber Clifford H.
Published: July 2021

The source-time functions of two microearthquakes with magnitudes 2.1 and 2.3 at Kilauea Volcano, Hawaii, are determined by using the deconvolution technique. P-wave seismograms of a smaller event with magnitude 1.6 in a nearby location are treated as empirical Green's functions and deconvolved from the waveforms of the larger earthquakes by spectral division. From the time-domain analysis of the source-time functions, some of the source properties, such as the complexity and directivity, and some of the source parameters, such as pulse width, rise time, and source dimension, are determined. With a good azimuthal distribution of stations, the direction and magnitude of rupture velocity are estimated for one of the events. The rupture direction is about N85°W and rupture velocity is 0.75 Vs, assuming Vp = 1.73 Vs. The result for direction agrees with one of the nodal planes of the focal mechanism. Our results indicate that there exist obvious variations in rupture durations for nearby small events with similar seismic moments, suggesting significant differences in the static stress drops. The stress drops of two events (1.5 and 16.5 bar) estimated from the rise times differ by an order of magnitude, implying heterogeneity of the stress distribution over this small area.
Time-domain response of a semi-circular canyon for incidentSV,P, and Rayleigh waves calculated by the discrete wavenumber boundary element method
Authors: Kawase H.
Published: July 2021

The responses of a semi-circular canyon for incident SH, SV, P, and Rayleigh waves in a two-dimensional elastic half-space are investigated in time domain as well as in frequency domain. The author proposes the discrete wavenumber boundary element method, in which the direct boundary element method is used with the discrete wavenumber Green's function. This combination achieves both the efficiency in computation and the flexibility for boundary configurations. First, the validity of the method is confirmed by comparing its results with published ones in frequency domain. Then time histories of seismic motion along the surface in and around the canyon are studied for incident SH, SV, P, and Rayleigh waves with the shape of a Ricker wavelet. In all cases, the diffracted waves called the creeping waves can be seen propagating inside the canyon with P- or S-wave velocity. For SV-wave incidence, Rayleigh waves generated at the edges of the canyon carry a significant portion of energy outward, while for SH-wave incidence the direct and reflected waves play a major role. It should be noted that the amplitude fluctuation in frequency domain does not always mean that in time domain because different arrival time of wavelets results in the fluctuation in spectral amplitude even if each wavelet propagates with the same shape and amplitude.
The earthquake hazard alert of September 1982 in Southern Tobago
Authors: Morgan F. D. , Wadge G. , Latchman J. , Aspinall W. P. , Hudson D. , Samstag F.
Published: July 2021

An earthquake swarm that occurred in the vicinity of the island of Tobago (West Indies) during the latter half of 1982 was monitored in the near-field by a five-station seismograph network. The monitoring of the swarm eventually led to the issuing of a potential earthquake hazard alert, 3 days prior to the major energy release (earthquake magnitude mb = 5.2). We discuss the reasons for issuing this alert. In particular, daily monitoring of the changing b value and energy release was used to constrain estimates of future earthquake behavior. The aftershock seismicity showed activity in a direction trending west to WNW. This is in good agreement with the focal mechanism of the main earthquake which showed right-lateral strike-slip motion along an E-W fault plane dipping steeply (71°) to the north. This active fault appears to form part of the previously unrecognized Southern Tobago Fault System for which there is evidence in the geology of the Late Neogene rocks of the island.
Seismic wave energy inferred from long-period body wave inversion
Authors: Kikuchi Masayuki , Fukao Yoshio
Published: July 2021

The seismic wave energy is evaluated for 35 large earthquakes by inverting far-field long-period P waves into the multiple-shock sequence. The results show that the seismic wave energy thus obtained is systematically less than that inferred from the Gutenberg-Richter's formula with the seismic magnitude. The difference amounts to one order of magnitude. The results also show that the energy-moment ratio is well confined to a narrow range: 10−6 < ES/Mo < 10−5 with the average of ∼5 × 10−6. This average value is exactly one order of magnitude as small as the energy-moment ratio inferred from the Gutenberg-Richter's formula using the moment magnitude. Comparing the energy-moment ratio with Δσo/2μ, where Δσo and μ are the stress drop and the rigidity, we obtain an empirical relation: ES/Mo ∼ 0.1 × Δσ0/2μ. Such a relation can be interpreted in terms of a subsonic rupture where the energy loss due to cohesion is not negligible to the seismic wave energy.
Attenuation of modified Mercalli intensity with distance in Mexico
Authors: Chávez Mario , Castro Raul
Published: July 2021

Two relations are proposed to predict the attenuation of Modified Mercalli Intensity (I) with distance (D) for Mexican earthquakes, i.e.

ln I = B 0 + B 1 ln ( D / D ' ) + B 2 ( D − D ' ) + B 3 ln M s ln I = B 0 + B 1 ( D / D ' ) + B 2 ln ( D − D ' ) + B 3 ln M s

Ms is the earthquake surface-wave magnitude, D′ is a distance related to the maximum I mapped for an earthquake, I′ or to Ms. The coefficients Bi, i = 0, 1, 2, 3 were obtained by fitting in a least-square sense the information contained in the intensity maps of 32 events to the relations. Those events were classified in three groups according to their epicentral location, focal mechanism, and depth, i.e., events related to the subduction-zone intermediate-depth earthquakes in south-central Mexico and to shallow crustal events along the Trans-Mexican Volcanic Belt.

The I predicted by the proposed relations compare well with the I observed for historical earthquakes not included in the fitting. Results obtained from a parametrical study showed that the attenuation of I with D is different for each of the three types of earthquakes. For distances of less than about 200 km, the earthquakes associated with the subduction zone have a larger attenuation than the ones originating in the south-central region of Mexico; for greater distances (D > 200 km), the opposite behavior is observed. The events located in the Trans-Mexican Volcanic Belt have a larger attenuation with distance than that of events in the other two regions. From these results, it seems advisable in Mexico to use several attenuation relations to estimate the seismic hazard at a site, depending on the particular tectonic setting and the path of the events under consideration.
A procedure for calibrating short-period telemetered seismograph systems
Authors: Chapman M. C. , Snoke J. A. , Bollinger G. A.
Published: July 2021

Efficient low-frequency calibration of the entire seismograph system can be accomplished by Fourier analysis of the system response to automatically generated transient test functions applied to the seismometer calibration coil. Typically, such calibrations are restricted to frequencies less than 10 Hz by the ambient ground motion, system noise, and limited dynamic range. To extend the calibration to a broader frequency range, we disconnect the seismometer and take advantage of the fact that the relative amplitude response of the electronic components in most systems can be measured with high accuracy at frequencies from as low as 0.02 Hz to the Nyquist frequency (e.g., 50 Hz) using standard electronics test equipment. The low-frequency amplitude response of the seismometer can then be isolated by dividing the total system response by that obtained for the electronic components. An iterative least-squares procedure is used to estimate the natural frequency and damping coefficient of the seismometer, along with a scaling parameter that specifies the absolute gain of the system. The phase response of the system is calculated directly from the amplitude response using the Hilbert transform. The procedure assumes that the seismometer is an ideal damped harmonic oscillator and that the system as a whole acts as a minimum phase filter. The only instrumental constants that must be known from independent measurement are the seismometer calibration coil force constant and the inertial mass.
Network-averaged teleseismicP-wave spectra for underground explosions. Part I. Definitions and examples
Authors: Murphy J. R. , Barker B. W. , O'Donnell A.
Published: July 2021

A new procedure is described for estimating network-averaged P-wave spectra from short-period, teleseismic recordings of explosions. This procedure is then applied to a large sample of approximately 1000 digitized Nevada Test Site (NTS) explosion seismograms to simultaneously derive estimates of frequency-dependent station correction factors and network-averaged P-wave spectra for each of the 50 selected explosions. An analysis of the station correction factors is then presented which demonstrates that the Veith-Clawson (1972) B(Δ) curve for time domain mb adequately describes the teleseismic distance dependence of the spectral amplitude data over the entire short-period band extending from 0.50 to 2.25 Hz. A simplified scaling analysis of the network-averaged spectra is described and used to confirm the fact that the P-wave source coupling characteristics below the water table at the Yucca Flat and Pahute Mesa testing areas of NTS are essentially identical. We conclude that this new spectral measure can provide robust means for comparing different explosion testing areas.
A satellite-based digital data system for low-frequency geophysical data
Authors: Silverman Stan , Mortensen Carl , Johnston Malcolm
Published: July 2021

A reliable method for collection, display, and analysis of low-frequency geophysical data from isolated sites, which can be throughout North and South America and the Pacific Rim, has been developed for use with the Geostationary Operational Environmental Satellite (GOES) system. Geophysical data primarily intended for earthquake hazard and crustal deformation monitoring are digitized with either 12-bit or 16-bit resolution and transmitted every 10 min through a satellite link to a bank of UNIX-based computers in Menlo Park, California. There the data are available for analysis and display within a few seconds of their transmit time. This system provides real-time monitoring of crustal deformation parameters such as tilt, strain, fault displacement, local magnetic field, crustal geochemistry, and water levels, as well as meteorological and other parameters, along faults in California and Alaska, and in volcanic regions in the western United States, Rabaul, and other locations in the New Britain region of the South Pacific. Various mathematical, statistical, and graphical algorithms process the incoming data to detect changes in crustal deformation and fault slip that may indicate the first stages of catastrophic fault failure. Alert trigger levels based on physical models, signal resolution, and previous history have been defined for particular instrument types. Computer-driven remote paging and mail systems are used to notify appropriate personnel when alarm status is reached. The system supports continuous historical records of low-frequency geophysical data, software for extensive analysis of these data, and programs for modeling fault rupture with and without seismic radiation, as well as providing an environment for real-time attempts at earthquake prediction.
An exact anelastic model for the free-surface relfection ofPandS-I waves
Authors: Borcherdt R. D. , Glassmoyer G.
Published: July 2021

Exact anelastic solutions incorporating inhomogeneous waves are used to model numerically S-I and P waves incident on the free surface of a low-loss anelastic half-space. Anelastic free-surface reflection coefficients are computed for the volumetric strain and displacement components of inhomogeneous wave fields. For the problem of an incident homogeneous S-I wave in Pierre shale, the largest strain and displacement amplitudes for the reflected P wave occur at angles of incidence for which the particle motion for the reflected inhomogeneous P wave is elliptical (minor/major axis = 0.6), the specific absorption (QP−1) is greater (300 per cent) and the velocity is less (25 per cent) than those for a corresponding homogeneous P wave, the direction of phase propagation is not parallel to the free surface, and the amplitude of the wave shows a significant increase with depth (6 per cent in one wavelength). Energy reflection coefficients computed for this low-loss anelastic model show that energy flow due to interaction of the incident and reflected waves reach maxima (30 per cent of the incident energy) near large but nongrazing angles of incidence. For the problem of an incident homogeneous P wave in Pierre shale, the inhomogeneity of the reflected S wave is shown not to contribute to significant variations in wave field characteristics over those that would be expected for a homogeneous wave.
High-frequencyP-wave attenuation determination using multiple-window spectral analysis method
Authors: Zhu Tianfei , Chun Kin-Yip , West Gordon F.
Published: July 2021

Yellowknife array (Northwest Territories, Canada) recordings of nuclear explosions detonated at French Tuamotu, South Pacific and Shagan River, Eastern Kazakhstan (USSR) test sites are used to derive t* values via the application of the spectral decay method. An important factor that limits the reliability of this widely used method is the degree of accuracy with which one is able to determine the signal spectral shape. For transient, pulse-like, short-period teleseismic phases, the conventional single-window spectral estimate methods may not be appropriate due to the trade-off betgween the leakage resistance and variance. A recently developed, multiple-window spectral analysis method is used in this study to effectively control spectral leakage, a capability that is especially important when analyzing seismic data characterized by a rapid high-frequency fall-off rate, such as the French Tuamotu explosion data. We compare the t* estimates obtained using a conventional single-window method with those obtained using the multiple-window method and show that the latter are more reliable. The t* (0.5 to 4.5 Hz) found by the multiple-window method for the Tuamotu-Yellowknife path is 0.66 sec. For the Eastern Kazakhstan-Yellowknife path, the multiple-window t* estimate is 0.42 sec in the 0.5 to 4.5 Hz range; a smaller value is obtained at higher frequencies (4.5 to 8 Hz).
A comparison of finite-difference and fourier method calculations of synthetic seismograms
Authors: Daudt C. R. , Braile L. W. , Nowack R. L. , Chiang C. S.
Published: July 2021

The Fourier method, the second-order finite-difference method, and a fourth-order implicit finite-difference method have been tested using analytical phase and group velocity calculations, homogeneous velocity model calculations for disperson analysis, two-dimensional layered-interface calculations, comparisons with the Cagniard-de Hoop method, and calculations for a laterally heterogeneous model. Group velocity rather than phase velocity dispersion calculations are shown to be a more useful aid in predicting the frequency-dependent travel-time errors resulting from grid dispersion, and in establishing criteria for estimating equivalent accuracy between discrete grid methods. Comparison of the Fourier method with the Cagniard-de Hoop method showed that the Fourier method produced accurate seismic traces for a planar interface model even when a relatively coarse grid calculation was used. Computations using an IBM 3083 showed that Fourier method calculations using fourth-order time derivatives can be performed using as little as one-fourth the CPU time of an equivalent second-order finite-difference calculation. The Fourier method required a factor of 20 less computer storage than the equivalent second-order finite-difference calculation. The fourth-order finite-difference method required two-thirds the CPU time and a factor of 4 less computer storage than the second-order calculation. For comparison purposes, equivalent runs were determined by allowing a group velocity error tolerance of 2.5 per cent numerical dispersion for the maximum seismic frequency in each calculation. The Fourier method was also applied to a laterally heterogeneous model consisting of random velocity variations in the lower half-space. Seismograms for the random velocity model resulted in anticipated variations in amplitude with distance, particularly for refracted phases.
Inversion of near-sourceSpolarization for parameters of double-couple point sources
Authors: Bernard Pascal , Zollo Aldo
Published: July 2021

We propose an inversion method for retrieving the focal parameters of small to moderate earthquakes by using the near-source S-wave polarizations, which are expected to be less sensitive than amplitude data to source details or propagation effects. We first studied the variability of the polarization vector for complete synthetic records generated in simple media with a shallow low-velocity layer, for various distances (0 to 50 km), source depths (1 to 15 km), and mechanisms. In the frequency band 1 to 2 Hz, a polarization fluctuation of less than 20° is found for sources deeper than 5 km. The mean angular difference between ray theory and complete field polarization is less than 10° when the complete waveform meets the two following criteria: (1) The polarization is nearly stable (less than 30° of variability) and (2) the motion is nearly horizontal (vector dip less than 30°).

The inversion method uses a norm related to the angular difference in polarization between the real and synthetic waveforms generated by a point double couple. As the problem is highly nonlinear, the model space (strike, dip, slip, location) should be finely sampled and systematically explored in the whole domain of interest. We tested the inversion resolution with synthetic data for a strike-slip and a dip-slip source at 10 km in depth (no error in location) recorded at eight stations within 30 km, assuming an error of 25° on the synthetic polarization. The dip-slip inversion gives a good resolution in dip (15° of uncertainty), but a strong correlation between strike and slip, because no recording site was close to the near vertical principal axis of the stress tensor in the test. On the contrary, the near horizontal major axis of the tensor is very well constrained. The strike-slip inversion gives a good resolution in the three parameters, with uncertainties of about 10°. A 25° change in the strike, dip, or slip angle statistically results in a 25° rotation of the polarization. With numerous stations, the overdetermination of the problem reduces the model error to values lower than 25°. The absence of records in specific areas introduces additional solutions for the possible mechanisms. Finally, the sensitivity of polarization to 3 km shift in source location is globally smaller than for 25° of rotation of any fault angle. The application of this method to real data requires the evaluation of the reliability in the polarizations computed for simplified media. An uncertainty of 25° is expected to be a reasonable assumption for distances smaller than 30 km in the 1 to 2 Hz frequency band; more generally, the error is expected to increase with distance and frequency.