scholarly journals Revised travel times in southern California*

1951 ◽  
Vol 41 (2) ◽  
pp. 143-163 ◽  
Author(s):  
B. Gutenberg
Keyword(s):  
Travel Time ◽  
Southern California ◽  
Origin Time ◽  
Transverse Waves ◽  
S Waves ◽  
Longitudinal And Transverse Waves ◽  
Wave Velocities ◽  
The Mean ◽  
The Difference ◽  
Interval Velocities

Abstract Discrepancies of up to 20 per cent between wave velocities calculated from blast records in southern California and those found from earthquakes necessitate a reinterpretation of seismograms of all near-by shocks and a revision of travel-time curves. A combination of findings for S — P intervals as a function of distance in southern California earthquake records with the ratio of mean interval velocities for P and S waves shows (without assumption of origin times) that the mean velocities of the two waves between the source and the surface are about 6.35 and 3.67 km/sec., respectively. This agrees with the results found from blast records. Most revised origin times are between ¾ sec. and 1 1/2 sec. later than those found previously from P¯. The method applied here removes the difference in origin time for longitudinal and transverse waves which was found formerly for earthquakes. Travel-time curves of various phases are revised and reinterpreted. The change in amplitudes with distance of several wave types is discussed.

scholarly journals The Walker Pass earthquakes and structure of the Southern Sierra Nevada*

1949 ◽  
Vol 39 (2) ◽  
pp. 93-107
Author(s):  
S. K. Chakrabarty ◽  
C. F. Richter
Keyword(s):  
Sierra Nevada ◽  
Southern California ◽  
Origin Time ◽  
Transverse Waves ◽  
Longitudinal And Transverse Waves ◽  
East And West

Summary The principal earthquake in the Walker Pass region on March 15, 1946, is located at 35°43'.5N,118°03'.3W, at a depth of 22 km., with origin time at 05:49:35.9 P.S.T. Epicenters of aftershocks scatter about this, with some indication of a NNE-SSW trend. The observed times fit a structure with layers 21.7 km., 9.7 km., and 10.7 km. thick. Velocities of the longitudinal and transverse waves agree with those previously determined by Gutenberg for southern California. The effect of the “root” of the Sierra Nevada is seen in the failure of Pn to record at Tinemaha, although it appears there on the seismograms of shocks east and west of the principal group.

scholarly journals Wave velocities in the earth's core

1958 ◽  
Vol 48 (4) ◽  
pp. 301-314
Author(s):  
B. Gutenberg
Keyword(s):  
Travel Time ◽  
Transition Zone ◽  
Southern California ◽  
Inner Core ◽  
Travel Times ◽  
Earth’S Core ◽  
Earth's Core ◽  
The Core ◽  
Wave Velocities

Abstract More than 700 seismograms of 39 shocks recorded mainly in southern California at epicentral distances between 105 and 140 degrees are used to investigate records of phases which have penetrated the earth's core. Properties of PKIKP, SKP, SKIKP, PKS, and PKIKS are discussed. Portions of travel-time curves of these phases are revised. Travel times of waves starting and ending at the surface of the core, and wave velocities in the core, are recalculated. Between about 1,500 and 1,200 km. from the earth's center in the transition zone from the liquid outer to the probably solid inner core, waves having lengths of the order of 10 km. travel faster than longer waves. This is probably caused by a rather rapid increase in viscosity toward the earth's center in this transition zone.

scholarly journals Apparent origin time of S̄ *

1943 ◽  
Vol 33 (4) ◽  
pp. 269-279
Author(s):  
B. Gutenberg ◽  
C. F. Richter
Keyword(s):  
Southern California ◽  
Travel Times ◽  
Fault Rupture ◽  
Origin Time ◽  
Transverse Waves ◽  
Longitudinal Waves ◽  
Fault Segment ◽  
Exact Theory

abstract Representative travel times for 50 shocks in southern California indicate that transverse waves appear to leave the focus about half a second earlier, on the average, than longitudinal waves. If fault rupture is propagated with a speed greater than that of transverse waves, the originating of such waves along a moderately extended fault segment will completely explain the observations. An exact theory is given on the simplest assumptions.

Azimuthal AVO for tilted TI medium

Geophysics ◽  
2017 ◽  
Vol 82 (1) ◽  
pp. C21-C33 ◽  
Author(s):  
Hongwei Wang ◽  
Suping Peng ◽  
Wenfeng Du
Keyword(s):  
Isotropic Medium ◽  
Symmetry Axis ◽  
Transversely Isotropic ◽  
P Wave ◽  
S Wave ◽  
Transverse Waves ◽  
Propagation Angle ◽  
S Waves ◽  
The Difference ◽  
Dip Angle

With the incident P-wave, we derive approximate formulas for amplitudes and polarizations of waves reflected from and transmitted through a planar, horizontal boundary between an overlying isotropic medium and an underlying tilted transversely isotropic (TTI) medium assuming that the directions of the phase and group velocities are consistent. Provided that the velocities in the isotropic medium are equal to the velocities along the symmetry axis direction, we derive the relational expression between the propagation angle in the TTI medium and the propagation angle in the hypothetical isotropic medium, under the condition that the horizontal slowness is the same, and then we update the approximate formula of the polarization in the TTI medium. Provided that the slow and fast transverse waves (qS and SH) are generated simultaneously in the anisotropic interface, we linearize for a six-order Zoeppritz equation, derive the azimuthal formula of longitudinal and S-waves, and determine their detailed expressions within the symmetry axis plane. According to the derived azimuthal AVO formula, we establish medium models, compare the derived AVO with the precision, and obtain the following conclusions: (1) The dip angle for the symmetry axis with respect to the vertical may have a sufficiently large impact on AVO, and the vertical longitudinal wave can generate an S-wave. (2) For the derived AVO formula, within the symmetry axis plane, the fitting effect of the approximate and exact formulas is good; however, within the other incident planes, taking the azimuth angle 45° as an example, the approximation is suitable for the large impedance contrast if the anisotropic parameters are set properly. (3) The error between the approximation and precision is mainly caused by the difference between the reflected and transmitted angles, the velocities’ derivation with respect to azimuth, and the division of approximation into isotropic and anisotropic parts.

scholarly journals SH travel times and lateral heterogeneities in the lower mantle

1973 ◽  
Vol 63 (6-1) ◽  
pp. 2035-2046
Author(s):  
Mansour Niazi
Keyword(s):  
Travel Time ◽  
Lower Mantle ◽  
Angular Distance ◽  
Travel Times ◽  
S Waves ◽  
The North ◽  
Lower Shear ◽  
Core Boundary ◽  
Mid Atlantic Ridge ◽  
The Difference

Abstract The horizontal long-period seismograms of two shallow earthquakes in Turkey and Iran recorded in selected azimuths are combined for travel-time studies of the SH wave beyond the angular distance of 40°. The observed travel times along two profiles which sample the deep mantle in the vicinity of Iceland and the North Pole show monotonically increasing differences beyond 65°, indicating lateral heterogeneity in the lower mantle. The travel-time difference becomes as large as 7 sec at 95°, implying a variation as much as 0.06 km/sec, or about 1 per cent, in the shear-wave velocity near 2,500 km depth. Inversion of observations, adjusted to surface foci, results in an average lower mantle structure with lower shear velocities than those given by Jeffreys. The difference exceeds 0.1 km/sec at the core boundary. The arrival time and signature of S waves recorded in Greenland show anomalous features which may be related to deep seated anomalous zones associated with the Mid-Atlantic Ridge system.

scholarly journals Travel times from blasts in southern California*

1951 ◽  
Vol 41 (1) ◽  
pp. 5-12 ◽  
Author(s):  
B. Gutenberg
Keyword(s):  
Southern California ◽  
Apparent Velocity ◽  
Travel Times ◽  
P Waves ◽  
Transverse Waves ◽  
Arrival Times ◽  
S Waves ◽  
Mohorovičić Discontinuity

abstract Seismograms recorded from a blast of about 70 tons of Du Pont “Nitramon” in tunnels at a quarry near Corona, southern California, are discussed. Arrival times of P waves indicate a velocity of between 5.7 and 6.0 km/sec. in the upper 6 km. of the region, and a velocity of about 6 1/2 km/sec. at a depth of 10 km. The Mohorovičić discontinuity is at a depth of the order of 40 km. The velocity below it is 8.1 to 8.2 km/sec. The amplitudes of S waves are only slightly more than one-tenth of those in an earthquake having P waves of equal amplitudes. The ratio of the velocity of P to that of the first recognizable S is found between 1.6 and 1.7. The first S waves at distances up to about 140 km. indicate a velocity of transverse waves of about 3¾ km/sec. at a depth of the order of 10 km. A phase with an apparent velocity of about 3 1/2 km/sec. can be traced to more than 400 km. It is followed by several slower phases. On the assumption that the amplitudes of Pn do not differ appreciably from those in an earthquake of the same magnitude, the blast would have had a magnitude of about 4.

The Effect of Vocabulary Intervention on Text Comprehension: Who Benefits?

2019 ◽  
Vol 50 (4) ◽  
pp. 562-578 ◽  
Author(s):  
Dawna Duff
Keyword(s):  
Middle School ◽  
Reading Comprehension ◽  
Text Comprehension ◽  
Classroom Instruction ◽  
Vocabulary Instruction ◽  
Clinical Intervention ◽  
Vocabulary Knowledge ◽  
Vocabulary Intervention ◽  
The Mean ◽  
The Difference

Purpose Vocabulary intervention can improve comprehension of texts containing taught words, but it is unclear if all middle school readers get this benefit. This study tests 2 hypotheses about variables that predict response to vocabulary treatment on text comprehension: gains in vocabulary knowledge due to treatment and pretreatment reading comprehension scores. Method Students in Grade 6 ( N = 23) completed a 5-session intervention based on robust vocabulary instruction (RVI). Knowledge of the semantics of taught words was measured pre- and posttreatment. Participants then read 2 matched texts, 1 containing taught words (treated) and 1 not (untreated). Treated texts and taught word lists were counterbalanced across participants. The difference between text comprehension scores in treated and untreated conditions was taken as a measure of the effect of RVI on text comprehension. Results RVI resulted in significant gains in knowledge of taught words ( d RM = 2.26) and text comprehension ( d RM = 0.31). The extent of gains in vocabulary knowledge after vocabulary treatment did not predict the effect of RVI on comprehension of texts. However, untreated reading comprehension scores moderated the effect of the vocabulary treatment on text comprehension: Lower reading comprehension was associated with greater gains in text comprehension. Readers with comprehension scores below the mean experienced large gains in comprehension, but those with average/above average reading comprehension scores did not. Conclusion Vocabulary instruction had a larger effect on text comprehension for readers in Grade 6 who had lower untreated reading comprehension scores. In contrast, the amount that children learned about taught vocabulary did not predict the effect of vocabulary instruction on text comprehension. This has implications for the identification of 6th-grade students who would benefit from classroom instruction or clinical intervention targeting vocabulary knowledge.

Efficacy and Safety of Oral Ivermectin and Topical Permethrin in the Treatment of Scabies

2020 ◽  
Vol 33 (1) ◽  
pp. 41-47
Author(s):  
Mohsena Akhter ◽  
Ishrat Bhuiyan ◽  
Zulfiqer Hossain Khan ◽  
Mahfuza Akhter ◽  
Gulam Kazem Ali Ahmad ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Close Contact ◽  
Randomized Study ◽  
Sarcoptes Scabiei ◽  
Efficacy And Safety ◽  
Common Skin ◽  
Group A ◽  
The Mean ◽  
The Difference ◽  
Group B

Background: Scabies is one of the most common skin diseases in our country. It is caused by the mite Sarcoptes scabiei var hominis, which is an ecto-parasite infesting the epidermis. Scabies is highly contagious. Prevalence is high in congested or densely populated areas. Individuals with close contact with an affected person should be treated with scabicidal which is available in both oral and topical formulations. The only oral but highly effective scabicidal known to date is Ivermectin. Amongst topical preparations, Permethrin 5 % cream is the treatment of choice. Objective: To evaluate the efficacy & safety of oral Ivermectin compared to topical Permethrin in the treatment of scabies. Methodology: This prospective, non-randomized study was conducted at the out-patient department of Dermatology and Venereology of Shaheed Suhrawardy Medical College & Hospital over a period of 6 months, from August 2016 to January 2017. The study population consisted of one hundred patients having scabies, enrolled according to inclusion criteria. They were divided into two groups. group A was subjected to oral Ivermectin and the group B to Permethrin 5% cream. Patients were followed up on day 7 and 14 for assessment of efficacy and safety. Result: The mean scoring with SD in group A (Ivermectin) and group B (Permethrin) were 8.26 ± 2.22 and 7.59 ± 2.01 respectively at the time of observation. The difference between the mean score of the two group is not significant (p=0.117) the mean scoring with SD in group A and group B were 4.54 ± 2.05 and 1.64 ± 1.84 respectively at 7thdays. The difference between the mean score of the two group is significant (p<0.001). The mean scoring with SD in group A and group B were 2.68± 2.35 and .36± 1.10 respectively at 14th day difference between the mean score of the group is significant (p<0.001). Conclusion: Topical application of permethrin 5% cream is more effective and safer than oral Ivermectin in the treatment of scabies. TAJ 2020; 33(1): 41-47

EFFECTS OF SYNTHETIC LH/FSH-RELEASING HORMONE (LRH) ON PLASMA LH AND FSH IN AMENORRHOEIC WOMEN

1974 ◽  
Vol 75 (4) ◽  
pp. 647-652 ◽  
Author(s):  
G. Rannevik ◽  
J. Thorell
Keyword(s):  
Urinary Excretion ◽  
Initial Response ◽  
Releasing Hormone ◽  
The Mean ◽  
The Difference ◽  
Serial Measurements

ABSTRACT Eight amenorrhoeic women were given 100 μg synthetic LRH (Hoechst) iv and im, respectively, at an interval of 2 weeks. Four of the women received the iv injection first and four the im injection. The urinary excretion of oestrogens and pregnanediol was low and unaltered throughout the test weeks. The effects of LRH were compared by serial measurements of the plasma LH and FSH during 8 h. The initial response of LH for up to 25 min and that of FSH for up to 60 min were equal whether LRH was given iv or im. The difference appeared later. Four hours after the injection the mean increase of LH to iv injection was 0.5 ng/ml (N. S.), while that to im injection was 1.9 ng/ml (P < 0.01). The corresponding values for FSH were 1.3 (P < 0.05) and 3.2 (P < 0.001). The effect of LRH administration im was thus found to be larger and more prolonged.

Development of Prolonged Delivery of Tramadol and Dissolution Translation by Statistical Data Treatment

2011 ◽  
Vol 4 (1) ◽  
pp. 1331-1337
Author(s):  
P B Parejiya ◽  
B S Barot ◽  
P K Shelat
Keyword(s):  
Drug Release ◽  
Study Data ◽  
Stability Study ◽  
Dissolution Time ◽  
Matrix Tablet ◽  
Burst Effect ◽  
The Matrix ◽  
The Mean ◽  
The Difference ◽  
Dissolution Efficiency

The present study was carried out to fabricate a prolonged design for tramadol using Kollidon SR (Polyvinyl acetate and povidone based matrix retarding polymer). Matrix tablet formulations were prepared by direct compression of Kollidon SR of a varying proportion with a fixed percentage of tramadol. Tablets containing a 1:0.5 (Drug: Kollidon SR) ratio exhibited a rapid rate of drug release with an initial burst effect. Incorporation of more Kollidon SR in the matrix tablet extended the release of drug with subsequent minimization of the burst effect as confirmed by the mean dissolution time, dissolution efficiency and f2 value. Among the formulation batches, a direct relationship was obtained between release rate and the percentage of Kollidon SR used. The formulation showed close resemblance to the commercial product Contramal and compliance with USP specification. The results were explored and explained by the difference of micromeritic characteristics of the polymers and blend of drug with excipients. Insignificant effects of various factors, e.g. pH of dissolution media, ionic strength, speed of paddle were found on the drug release from Kollidon-SR matrix. The formulation followed the Higuchi kinetic model of drug release. Stability study data indicated stable character of Batch T6 after short-term stability study.

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