Establishment of the Mediterranean fruit fly in California

Principles of invasion biology are brought to bear on the question of whether the medfly is established in California. Since its first discovery in 1975, the pest has been captured in the Los Angeles Basin in nine separate years including every year from 1986 through 1990. The trend has become distinct--the intervals between captures are decreasing, the numbers captured are increasing, and the area over which they are detected is expanding. In addition, appearances are seasonal and captures in recent years have occurred in many of the same cities and neighborhoods where medflies were found several years before. Evidence suggests that the medfly may be established in the Los Angeles area and that previous eradication programs did not eradicate the medfly from California. It follows that detection, exclusion, and eradication protocols may need to be reexamined.     

Industrial air pollution: possible effect on lung cancer

Higher lung cancer mortality rates occurred in males living in certain heavily industrialized areas of Los Angeles County, California. These areas were characterized by elevated concentrations of benzo[a]pyrene and other polynuclear aromatic hydrocarbons of primarily industrial origin in the soil and air.     

Chemical composition of Acid fog

Fog water collected at three sites in Los Angeles and Bakersfield, California, was found to have higher acidity and higher concentrations of sulfate, nitrate, and ammonium than previously observed in atmospheric water droplets. The pH of the fog water was in the range of 2.2 to 4.0. The dominant processes controlling the fog water chemistry appear to be the condensation and evaporation of water vapor on preexisting aerosol and the scavenging of gas-phase nitric acid.     

DDT residues: distribution of concentrations in Emerita analoga (stimpson) along coastal California

The total concentrations (tDDT) of DDT [1,1,1-trichloro-2,2-bis(pchlorophenyl)ethane], DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethanel, and DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] in Emerita analoga from 19 California beaches reflect tDDT contamination nearby. Animals near the Los Angeles County sewer outfall contain over 45 times as much tDDT as animals near major agricultural drainage areas. Sediments near the outfall probably contain over 100 metric tons of tDDT-a reservoir for input into marine organisms. The effluent from a plant that manufactures DDT is a probable source.     

Fault interactions and large complex earthquakes in the Los Angeles area

Faults in complex tectonic environments interact in various ways, including triggered rupture of one fault by another, that may increase seismic hazard in the surrounding region. We model static and dynamic fault interactions between the strike-slip and thrust fault systems in southern California. We find that rupture of the Sierra Madre-Cucamonga thrust fault system is unlikely to trigger rupture of the San Andreas or San Jacinto strike-slip faults. However, a large northern San Jacinto fault earthquake could trigger a cascading rupture of the Sierra Madre-Cucamonga system, potentially causing a moment magnitude 7.5 to 7.8 earthquake on the edge of the Los Angeles metropolitan region.     

Economic feasibility of solar water and space heating

The economic feasibility in 1977 and 1978 of solar water and combined water and space heating is analyzed for single-family detached residences and multi-family apartment buildings in four representative U.S. cities: Boston, Massachusetts; Washington, D.C.; Grand Junction, Colorado; and Los Angeles, California. Three economic decision criteria are utilized: payback period, years to recovery of down payment, and years to net positive cash flow. The cost competitiveness of the solar systems compared to heating systems based on electricity, fuel oil, and natural gas is then discussed for each city, and the impact of the federal tax credit for solar energy systems is assessed. It is found that even without federal incentives some solar water and space heating systems are competitive. Enactment of the solar tax credit, however, greatly enhances their competitiveness. The implications of these findings for government tax and energy pricing policies are discussed.     

Requirements for Floral Initiation of Los Angeles Xanthium

Cocklebur from the Los Angeles area was found to require more extensive short-day treatment for floral initiation than plants of the same species from the Chicago region. Data obtained by grafting the two regional types of cocklebur indicate that the leaves of the Los Angeles Xanthium produce a comparatively low amount of the flowering stimulus.     

Erratum

The address given for Small Talk/V, Digitalk, Inc., in reference 2 of the software review "PC sofotware for artificial intelligence applications" by Helmut Epp et al. (6 May, p. 824) was incorrect. It should have been 9841 Airport Boulevard, Los Angeles, CA 90045.     

Erratum

In Eliot Marshall's article "Reinventing the space truck" (News & Comment, 16 Oct., p. 266), the photo identification was reversed. The Martin Marietta rocket design was on the right, and the Hughes Aircraft design was on the left. Also, the Air Force's Space Division is in Los Angeles, not Denver.     

Prospects for larger or more frequent earthquakes in the los angeles metropolitan region

Far too few moderate earthquakes have occurred within the Los Angeles, California, metropolitan region during the 200-year-long historic period to account for observed strain accumulation, indicating that the historic era represents either a lull between clusters of moderate earthquakes or part of a centuries-long interseismic period between much larger (moment magnitude, M(w), 7.2 to 7.6) events. Geologic slip rates and relations between moment magnitude, average coseismic slip, and rupture area show that either of these hypotheses is possible, but that the latter is the more plausible of the two. The average time between M(w) 7.2 to 7.6 earthquakes from a combination of six fault systems within the metropolitan area was estimated to be about 140 years.     

A 100-year average recurrence interval for the san andreas fault at wrightwood, california

Evidence for five large earthquakes during the past five centuries along the San Andreas fault zone 70 kilometers northeast of Los Angeles, California, indicates that the average recurrence interval and the temporal variability are significantly smaller than previously thought. Rapid sedimentation during the past 5000 years in a 150-meter-wide structural depression has produced a greater than 21-meter-thick sequence of debris flow and stream deposits interbedded with more than 50 datable peat layers. Fault scarps, colluvial wedges, fissure infills, upward termination of ruptures, and tilted and folded deposits above listric faults provide evidence for large earthquakes that occurred in A.D. 1857, 1812, and about 1700, 1610, and 1470.     

Evidence for large earthquakes in metropolitan los angeles

The Sierra Madre fault, along the southern flank of the San Gabriel Mountains in the Los Angeles region, has failed in magnitude 7.2 to 7.6 events at least twice in the past 15,000 years. Restoration of slip on the fault indicated a minimum of about 4.0 meters of slip from the most recent earthquake and suggests a total cumulative slip of about 10.5 meters for the past two prehistoric earthquakes. Large surface displacements and strong ground motions resulting from greater than magnitude 7 earthquakes within the Los Angeles region are not yet considered in most seismic hazard and risk assessments.     

Recognition of paleoearthquakes on the Puente Hills blind thrust fault,California

Borehole data from young sediments folded above the Puente Hills blind thrust fault beneath Los Angeles reveal that the folding extends to the surface as a discrete zone (相似文献   

The 1987 whittier narrows earthquake in the los angeles metropolitan area, california

The Whittier Narrows earthquake sequence (local magnitude, M(L) = 5.9), which caused over $358-million damage, indicates that assessments of earthquake hazards in the Los Angeles metropolitan area may be underestimated. The sequence ruptured a previously unidentified thrust fault that may be part of a large system of thrust faults that extends across the entire east-west length of the northern margin of the Los Angeles basin. Peak horizontal accelerations from the main shock, which were measured at ground level and in structures, were as high as 0.6g (where g is the acceleration of gravity at sea level) within 50 kilometers of the epicenter. The distribution of the modified Mercalli intensity VII reflects a broad north-south elongated zone of damage that is approximately centered on the main shock epicenter.     

The magnitude 6.7 northridge, california, earthquake of 17 january 1994

The most costly American earthquake since 1906 struck Los Angeles on 17 January 1994. The magnitude 6.7 Northridge earthquake resulted from more than 3 meters of reverse slip on a 15-kilometer-long south-dipping thrust fault that raised the Santa Susana mountains by as much as 70 centimeters. The fault appears to be truncated by the fault that broke in the 1971 San Fernando earthquake at a depth of 8 kilometers. Of these two events, the Northridge earthquake caused many times more damage, primarily because its causative fault is directly under the city. Many types of structures were damaged, but the fracture of welds in steel-frame buildings was the greatest surprise. The Northridge earthquake emphasizes the hazard posed to Los Angeles by concealed thrust faults and the potential for strong ground shaking in moderate earthquakes.     

Ozone control and methanol fuel use

Methanol fuel use in motor vehicles and stationary combustion has the potential to improve air quality. A modeling study of methanol fuel use in Los Angeles, California, shows that the low chemical reactivity of methanol vapor slows ozone formation and would lead to lower ozone concentrations. Predicted peak ozone levels decreased up to 16 percent, and exposure to levels above the federal standard dropped by up to 22 percent, when pure (M100) methanol fuel use was simulated for the year 2000. Similar results were obtained for 2010. Use of a gasoline-methanol blend (M85) resulted in smaller reductions. Predicted formaldehyde levels and exposure were not increased severely, and in some cases declined, in the simulations of methanol use.     

Erratum

In the article "Women scientists and engineers: Trends in participation," by, Betty M. Vetter (18 Dec., p. 1313), a study by C. Rose was incorrectly cited in reference 12. The correct citation is C. Rose, Academic Employment and Graduate Enrollment Pattern and Trends of Women in Science and Engineering (Final Technical Report to the National Science Foundation, Evaluation and Training Institute, Los Angeles, Calif., 1978).     

Erratum

In the article "Mathematicians recognize major discoveries" by Gina Kolata (Research News, 15 Aug., p. 722), Fields Medal winner Michael Freedman was incorrectly described as being a member of the University of Southern California faculty. Freedman is Charles Lee Powell Professor of Mathematics at the University of California, San Diego. In addition, several names in the article were spelled incorrectly. Field's should have been Fields, Nevalinna and Navanlinna should have been Nevanlinna, Kirky should have been Kirby, Aryiyah should have been Atiyah, and Strasen should have been Strassen.     

Erratum

In the article " ;Nuclear winter' from Gulf war discounted," by Eliot Marshall (News & Comment, 25 Jan., p. 372), Tica Novakov's affiliation should have been given as the Lawrence Berkeley Laboratory, not the Lawrence Livermore National Laboratory. The concentrations of airborne soot reported at various locations should have been given as follows: for greater Los Angeles (summer), a daily average of 5 micrograms per cubic meter; Beijing (winter), a monthly average of 50 micrograms per cubic meter; Yugoslavia (winter), a daily average of 60 micrograms; and London (1-day winter peak in 1952), 750 micrograms, now reduced to less than 15 micrograms.     

Correction

In the 24 April "Inside AAAS" article "AAAS organizes more meetings of the mind" (p. 548), it is stated incorrectly that Paul Berg of Stanford University will be giving the keynote address and that Helen Donis-Keller of Washington University will be presenting a paper at the Science Innovation '92 meeting in San Francisco (21 to 25 July 1992). The Science Innovation '92 program was tentative at the time the article was written. Joseph Martin of the University of California, San Francisco, will deliver the keynote address on one of the major themes of the meeting, "Mapping the Human Brain." Helen Donis-Keller and Paul Berg were invited to speak but will not be on the program this year.