摘要:

Alvarez[1986] recently summarized inEosthe evidence for the hypothesis that an impact was actually responsible for the terminal Cretaceous events. Alvarez reviewed the physical and chemical evidence for an impact; at the same time, he provided an interesting account of how quickly ideas evolved after the original discovery, by himself and his colleagues [Alvarez et al., 1980], of a conspicuous iridium anomaly at the Cretaceous‐Tertiary boundary (also known as the KTB). An alternate hypothesis is a volcanic (either quiet basaltic or violent siliceous) origin for the KTB [e.g,Officer and Drake, 1983, 1985]. Alvarez summarized his observations with a table [Alvarez, 1986, Table 1, p. 649] in which each hypothesis is tested against the following evidence: iridium, spherules, shocked quartz, soot, and worldwide distribution. The “yes” and “no” answers to these tests are, of course, a function of present data and knowledge. The purpose of this article is to stress that answers have changed rapidly in recent years and may still evolve, and also that Alvarez's declaration that the case for a volcanic cause is extinct may be somewhat

ISSN:0002-8606    

DOI:10.1029/EO068i014p00193

年代:1987

数据来源: WILEY

摘要:

The National Science Foundation (NSF) requires a triennial review of each of its programs. The review is normally carried out by a subcommittee of the external scientific advisory committee for the division. The charge to the review committee is “to provide NSF management with an advisory appraisal of the technical . . . stewardship by the NSF.” Topics to be addressed include the selection of mail reviewers, justification of the funding decision by the program officer, and assessment of any apparent imbalances in awa

ISSN:0002-8606    

DOI:10.1029/EO068i014p00194

年代:1987

数据来源: WILEY

摘要:

Results from new computer models that could allow policymakers to compare different strategies for controlling acid rain will be presented at the AGU Spring Meeting in Baltimore, Md., May 18–21, 1987. The optimization models, developed by scientists from the Johns Hopkins University (Baltimore, Md.), are set up so that competing goals—for instance, reducing the deposition of sulfur without wiping out the high‐sulfur coal industry— can be taken into

ISSN:0002-8606    

DOI:10.1029/EO068i014p00196-01

年代:1987

数据来源: WILEY

摘要:

The October 21, 1986, issue ofEoshad an attractive cover showing the Viking satellite in space near the earth. It also showed an artist's rendition of the magnetic field lines of the earth. Since the field lines were symmetric (see Figure 1 for a version of the cover), and the closed lines that were shown only extended out to about 2 REfrom the earth's center, I would have expected the lines to be those of a dipole. However, a dipole field line pattern is characterized by “lobes” that are comparatively long and narrow in a direction perpendicular to the dipole axis, and the field lines on theEoscover were too compressed along the equatorial dimension to meet that criterion. Something was wr

ISSN:0002-8606    

DOI:10.1029/EO068i014p00197-02

年代:1987

数据来源: WILEY

摘要:

Fraser‐Smith's complaint about dipole field lines being scrunched up in illustrations is much ado about very little. On one memorable occasion, one of us did much worse (see Figure 1); he is still wondering how it happened! The point is that most drawings of the dipole field are cartoons and use a good measure of artistic license, especially artistic renditions like the one gracing the cover ofEoson October 21, 1986, showing fluffy suggestions of field lines with vague overtones of auroral arcs.To the best of our knowledge, no erroneous physical conclusion ever arose from such a cartoon, though a considerable amount of journal space may have been saved. Purists may argue about accuracy, but most readers will agree that, like contact lenses, dipolarity is mostly in the eyes of the beholde

ISSN:0002-8606    

DOI:10.1029/EO068i014p00198

年代:1987

数据来源: WILEY

摘要:

Eville Gorham, Regents Professor of Ecology and Botany at the University of Minnesota, is the 1986 recipient of the Hutchinson Award. The medallion and certificate that constitute the award are given annually by the American Society of Limnology and Oceanography (ASLO) in recognition of outstanding research. The award was presented to Gorham by G.E. Hutchinson (Yale University, New Haven, Conn.) at a banquet in Newport, R.I., during the ASLO summer meeting.

ISSN:0002-8606    

DOI:10.1029/EO068i014p00199-01

年代:1987

数据来源: WILEY

摘要:

A Chapman Conference entitled “Microbial Processes in the Transport, Fate, and In Situ Treatment of Subsurface Contaminants” was held in Snowbird, Utah, October 1–3, 1986. Members of the program committee and session chairmen were Lenore Clesceri (Rensselaer Polytechnic Institute, Troy, N.Y.), David Gibson (University of Texas, Austin), James Mercer (GeoTrans, Inc., Herndon , Va.), Donald Michelsen (Virginia Polytechnic Institute and State University, Blacksburg), Fred Molz (Auburn University, Auburn, Ala.), Bruce Rittman (University of Illinois, Urbana), Gary Sayler (University of Tennessee, Knoxville), and John T. Wilson (U.S. Environmental Protection Agency, Ada, Okla.). The following report attempts to highlight the six sessions that constituted the conference. For additional information, including a bound summary and abstracts, contact Fred J. Molz, Civil Engineering Department, Auburn University, AL 36849 (telephone: 205‐82

ISSN:0002-8606    

DOI:10.1029/EO068i014p00204

年代:1987

数据来源: WILEY

ISSN:0002-8606    

DOI:10.1029/EO068i014p00205

年代:1987

数据来源: WILEY

摘要:

Current perceptions of day‐care programs, philosophies of how day‐care facilities should be run, and popular books on the subject were the topics of a special evening session sponsored by the Committee on Education and Human Resources at the 1986 AGU Fall Meeting in San Francisco, Calif. The session, which was attended by about 20 people, featured Patricia Bourne, a sociologist who specializes in federal and local day‐care p

ISSN:0002-8606    

DOI:10.1029/EO068i014p00206

年代:1987

数据来源: WILEY