Static corrections on the southeastern Piedmont of the United States

Geophysics ◽  
1982 ◽  
Vol 47 (11) ◽  
pp. 1540-1549 ◽  
Author(s):  
Michael S. Bahorich ◽  
Cahit Coruh ◽  
Edwin S. Robinson ◽  
John K. Costain
Keyword(s):  
United States ◽  
The United States ◽  
Weathered Zone ◽  
Common Depth Point ◽  
Position Data ◽  
First Arrival ◽  
Static Corrections ◽  
Metamorphic Terrane ◽  
Thickness Variations ◽  
Refracted Waves

On the Piedmont of the southeastern United States, seismic reflection statics at different points in a typical common‐depth‐point (CDP) gather can differ from one another by more than 50 msec because of topographic relief in excess of 50 m, variations in the thickness of the weathered zone that can extend deeper than 50 m, and variation of velocity in the weathered zone of more than 100 m/sec. The ABCD method for computing statics is introduced to account for these velocity and thickness variations as well as the topographic effect. This method combines elevations and positions of source‐receiver points with times of first arriving refracted waves read from reflection correlograms or seismograms. It was tested in central Virginia where typical piedmont conditions are encountered. At four locations, ABCD statics are close to control values determined independently from refraction experiments. At 99 source‐detector points, ABCD statics differ by an average of 4 msec, (maximum of 19 milliseconds) from conventional elevation statics that do not account for local velocity thickness variations in the weathered zone. Where source‐receiver points were in line, modified ABCD statics were obtained from first arrival traveltimes without using elevation and position data. In this metamorphic terrane where clear reflections are difficult to record, ABCD statics appear to be more effective than conventional elevation statics for enhancing reflections on a seismic record section.

Gender Differences in Pediatric Dentistry Chairs in the United States and Canada

2020 ◽  
Vol 44 (5) ◽  
pp. 323-331
Author(s):  
Janice A Townsend ◽  
Marcio A da Fonseca ◽  
Tobias E Rodriguez ◽  
Charles W LeHew
Keyword(s):  
United States ◽  
Gender Differences ◽  
Time Management ◽  
Department Chairs ◽  
The United States ◽  
Pediatric Dentistry ◽  
Academic Leaders ◽  
Position Data ◽  
Professional History ◽  
Job Perceptions

Objective: To analyze gender differences in personal and professional demographics, job perceptions and work satisfaction between male and female pediatric dentistry academic leaders in the United States and Canada. Study Design: A 40-question survey was sent electronically to department chairs requesting information about demographics, current circumstances of the position, professional history, and opinions about the position. Data was analyzed by the sex of the respondent. Results: Eighty-eight surveys were distributed electronically and 55 chairs responded (response rate: 62.5%). Women comprised 29.5% of the sample, were younger and had less leadership training than men. Men had served longer in the position (t(41)=2.02, p=0.05) and had higher ranking academic titles. Women spent more time managing personnel (p=0.026), creating courses and programs (p=0.029), and teaching (p=0.006) than men. Female chairs perceived to have a difficult relationship with the faculty (p=0.027), felt they received less faculty support (p=0.002), and were significantly more dissatisfied in the job (p=0.037). Men were more stressed about a heavy workload than women (p=0.001). Conclusion: Gender was significantly related to the demographics, experience, perceptions of the skills and abilities required for job performance, time management and job satisfaction for pediatric dentistry department chairs in American and Canadian institutions.

scholarly journals Static corrections from shallow‐reflection surveys

Geophysics ◽  
1990 ◽  
Vol 55 (6) ◽  
pp. 769-775 ◽  
Author(s):  
D. W. Steeples ◽  
R. D. Miller ◽  
R. A. Black
Keyword(s):  
Layer Thickness ◽  
Seismic Reflection ◽  
P Wave ◽  
Thickness Variation ◽  
Near Surface ◽  
Weathered Zone ◽  
Reflection Data ◽  
Weathered Layer ◽  
Static Corrections ◽  
Thickness Variations

Shallow seismic reflection surveys can assist in determination of velocity and/or thickness variations in near‐surface layers. Static corrections to seismic reflection data compensate for velocity and thickness variations within the “weathered zone.” An uncompensated weathered‐layer thickness variation on the order of 1 m across the length of a geophone array can distort the spectrum of the signal and result in aberrations on final stacked data. P-wave velocities in areas where the weathered zone is composed of unconsolidated materials can be substantially less than the velocity of sound in air. Weathered‐layer thickness variation of 1 m in these low‐velocity materials could result in a static anomaly in excess of 3 ms. Shallow‐reflection data from the Texas panhandle illustrate a real geologic situation with sufficient variability in the near surface to significantly affect seismic signal reflected from depths commonly targeted by conventional reflection surveys. Synthetic data approximating a conventional reflection survey combined with a weathered‐layer model generated from shallow‐reflection data show the possible dramatic static effects of alluvium. Shallow high‐resolution reflection surveys can be used both to determine the severity of intra‐array statics and to assist in the design of a filter to remove much of the distortion such statics cause on deeper reflection data. The static effects of unconsolidated materials can be even more dramatic on S-wave reflection surveys than on comparable P-wave surveys.

scholarly journals Do Immigrants Assimilate More Slowly Today than in the Past?

2020 ◽  
Vol 2 (1) ◽  
pp. 125-141 ◽  
Author(s):  
Ran Abramitzky ◽  
Leah Boustan ◽  
Katherine Eriksson
Keyword(s):  
United States ◽  
The United States ◽  
Birth Certificates ◽  
Cultural Assimilation ◽  
The Past ◽  
Education Levels ◽  
First Arrival

Using millions of historical census records and modern birth certificates, we document that immigrants assimilated into US society at similar rates in the past and present. We measure cultural assimilation as immigrants giving their children less foreign names after spending more time in the United States, and show that immigrants erase about one‑half of the naming gap with natives after 20 years both historically and today. Immigrants from poorer coun‑ tries choose more foreign names upon first arrival in both periods but are among the fastest to shift toward native‑sounding names. We find substantial cultural assimilation for immigrants of all education levels. (JEL J15, N31, N32, Z13)

Party Strength in the United States: Some Corrections

1975 ◽  
Vol 37 (2) ◽  
pp. 641-642 ◽  
Author(s):  
Paul T. David
Keyword(s):  
United States ◽  
The United States ◽  
Party Strength

Correlative microscopy in distrubuted (client/server) computing environments: tools for catalyzing the rapid dissemination of information about the cell biology of the human prostate

1995 ◽  
Vol 53 ◽  
pp. 682-683
Author(s):  
A. Hakam ◽  
J.T. Gau ◽  
M.L. Grove ◽  
B.A. Evans ◽  
M. Shuman ◽  
...  
Keyword(s):  
United States ◽  
Cell Biology ◽  
Tissue Bank ◽  
The United States ◽  
Prostate Adenocarcinoma ◽  
Correlative Microscopy ◽  
Client Server ◽  
Critical Elements ◽  
Transplant Organ

Prostate adenocarcinoma is the most common malignant tumor of men in the United States and is the third leading cause of death in men. Despite attempts at early detection, there will be 244,000 new cases and 44,000 deaths from the disease in the United States in 1995. Therapeutic progress against this disease is hindered by an incomplete understanding of prostate epithelial cell biology, the availability of human tissues for in vitro experimentation, slow dissemination of information between prostate cancer research teams and the increasing pressure to “ stretch” research dollars at the same time staff reductions are occurring.To meet these challenges, we have used the correlative microscopy (CM) and client/server (C/S) computing to increase productivity while decreasing costs. Critical elements of our program are as follows:1) Establishing the Western Pennsylvania Genitourinary (GU) Tissue Bank which includes >100 prostates from patients with prostate adenocarcinoma as well as >20 normal prostates from transplant organ donors.

Digital image acquisition, processing, and analysis in a polymer microscopy laboratory

1994 ◽  
Vol 52 ◽  
pp. 454-455
Author(s):  
Vinod K. Berry ◽  
Xiao Zhang
Keyword(s):  
United States ◽  
Image Analysis ◽  
Digital Image ◽  
Image Acquisition ◽  
Image Transmission ◽  
The United States ◽  
Quantitative Image Analysis ◽  
Quantitative Image

In recent years it became apparent that we needed to improve productivity and efficiency in the Microscopy Laboratories in GE Plastics. It was realized that digital image acquisition, archiving, processing, analysis, and transmission over a network would be the best way to achieve this goal. Also, the capabilities of quantitative image analysis, image transmission etc. available with this approach would help us to increase our efficiency. Although the advantages of digital image acquisition, processing, archiving, etc. have been described and are being practiced in many SEM, laboratories, they have not been generally applied in microscopy laboratories (TEM, Optical, SEM and others) and impact on increased productivity has not been yet exploited as well.In order to attain our objective we have acquired a SEMICAPS imaging workstation for each of the GE Plastic sites in the United States. We have integrated the workstation with the microscopes and their peripherals as shown in Figure 1.

Silence of the Land: On the Historical Irrelevance of Territory to Congressional Districting and Political Representation in the United States

2001 ◽  
Vol 15 (01) ◽  
pp. 53-87 ◽  
Author(s):  
Andrew Rehfeld
Keyword(s):  
United States ◽  
House Of Representatives ◽  
Political Representation ◽  
The United States ◽  
Representative Government ◽  
Congressional District ◽  
Congressional Districts ◽  
Communities Of Interest

Every ten years, the United States “constructs” itself politically. On a decennial basis, U.S. Congressional districts are quite literally drawn, physically constructing political representation in the House of Representatives on the basis of where one lives. Why does the United States do it this way? What justifies domicile as the sole criteria of constituency construction? These are the questions raised in this article. Contrary to many contemporary understandings of representation at the founding, I argue that there were no principled reasons for using domicile as the method of organizing for political representation. Even in 1787, the Congressional district was expected to be far too large to map onto existing communities of interest. Instead, territory should be understood as forming a habit of mind for the founders, even while it was necessary to achieve other democratic aims of representative government.

A quarter century of changes in oral health in the United States

1995 ◽  
Vol 59 (1) ◽  
pp. 19-57 ◽  
Author(s):  
BA White ◽  
DJ Caplan ◽  
JA Weintraub
Keyword(s):  
United States ◽  
Oral Health ◽  
The United States ◽  
Quarter Century
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