Small Solar Wind Transients and Their Connection to the Large-Scale Coronal Structure

It has been realized for some time that the slow solar wind with its embedded heliospheric current sheet often exhibits complex features suggesting at least partially transient origin. In this paper we investigate the structure of the slow solar wind using the observations by the Wind and STEREO spacecraft during two Carrington rotations (2054 and 2055). These occur at the time of minimum solar activity when the interplanetary medium is dominated by recurrent high-speed streams and large-scale interplanetary coronal mass ejections (ICMEs) are rare. However, the signatures of transients with small scale-sizes and/or low magnetic field strength (comparable with the typical solar wind value, ～?5 nT) are frequently found in the slow solar wind at these times. These events do not exhibit significant speed gradients across the structure, but instead appear to move with the surrounding flow. Source mapping using models based on GONG magnetograms suggests that these transients come from the vicinity of coronal source surface sector boundaries. In situ they are correspondingly observed in the vicinity of high density structures where the dominant electron heat flux reverses its flow polarity. These weak transients might be indications of dynamical changes at the coronal hole boundaries or at the edges of the helmet streamer belt previously reported in coronagraph observations. Our analysis supports the idea that even at solar minimum, a considerable fraction of the slow solar wind is transient in nature.     

Ecology,sedimentology, and diagenesis of recent and fossil reefs

At the VIII. International Sedimentological Congress held in Heidelberg in 1971, a symposium with the above title was convened; a selection of the papers presented is assembled in this issue. In the introduction the approaches of the following studies are reviewed to show some trends and problems in reef research.     

AAFE RADSCAT 13.9-GHz measurements and analysis: Wind-speed signature of the ocean

About 10 years ago, the advanced application flight experiment radiometer scatterometer (AAFE RADSCAT) made its first successful measurements of ocean radar scattering cross section from a NASA C-130 aircraft. This instrument was developed as a research tool to evaluate the use of microwave frequency remote sensors (particularly radars) to provide wind-speed information at the ocean's surface. The AAFE RADSCAT flight missions and analyses helped establish the feasibility of the satellite scatterometer for measuring both wind speed and direction. Probably the most important function of the AAFE RADSCAT was to provide a data base of ocean normalized radar cross-section (NRCS) measurements as a function of the surface wind vector at 13.9 GHz. NRCS measurements over a wide parametric range of incidence angles, azimuth angles, and winds were obtained in a series of RADSCAT aircraft missions from 1973 to 1977. Presented herein are analyses of data from the 26 RADSCAT flights during which the quality of the sensor and the surface wind measurements were felt to be understood. Subsets of this data base were used to model the relationship between theKu-band radar signature and the ocean-surface wind vector. The models developed partly from portions of this data base, supplemented with data from the Seasat (JASIN Report), were used for inversion of the Seasat-A Satellite Scatterometer (SASS) radar measurements to vector winds. This paper summarizes results from a comprehensive analysis of the RADSCAT/ocean wind signature deduced from this complete data set.     

Tanzanite as conflict gem: Certifying a secure commodity chain in Tanzania

Shortly after the September 11, 2001 attacks in the United States, the Wall Street Journal published an article claiming that al Qaeda sympathizers were using an obscure gemstone commodity known as tanzanite to raise funds for terrorist activities. Despite subsequent disclaimers by the US State Department, this allegation effectively marked tanzanite as a “conflict gem,” and set in motion a complex set of political maneuvers designed to rehabilitate the tanzanite industry’s reputation. This paper analyzes the immediate fallout from the Wall Street Journal article and the subsequent effects of anti-terrorist rhetoric on the tanzanite industry. I explore the origins of the “conflict gem” discourse and the political movement that has taken shape over the past decade to reform gemstone mining. Drawing on theories developed by critics of the fair trade movement, I examine a series of steps taken by the main corporate miner active in the tanzanite industry to re-brand and certify tanzanite as “conflict-free.” I underscore the degree to which these efforts have been inflected by new security provisions embodied in the USA Patriot Act.     

The future economic role of European Marginal seas: The pontus

Reports

The future economic role of European Marginal seas: The pontus     

Drivers of social media use among African Americans in the event of a crisis

Research has examined the role of social media during the time of a crisis in various fields; however, there is a paucity of research in this area as it relates to tourism. Moreover, few studies have examined at-risk populations, such as tourists, in times of crisis. To assess the drivers of turning to social media during a crisis, a national survey of 1,018 African American travelers was conducted. Respondents were asked to indicate on a 5-point scale the likelihood of turning to social media for information “if they were currently in the middle of their trip and heard that a crisis has just occurred within the immediate vicinity of their current location.” Hierarchical regression analysis was conducted to determine drivers on African American travelers’ decisions to use social media during a crisis. These drivers were age, perceptions of risk during their trip, and frequency and type of social media use engaged in on a regular basis. Overall, findings suggested that when controlling for age only, crime, financial, and physical perceptions of risk drove social media use during a crisis, while controlling for age and perception of risk, use of social media in one's daily life showed no influence.     

ENSO and seasonal sea-level variability – A diagnostic discussion for the U.S.-Affiliated Pacific Islands

Summary The El Ni?o-Southern Oscillation (ENSO) climate cycle is the basis for this paper, aimed at providing a diagnostic outlook on seasonal sea-level variability (i.e. anomalies with respect to the Climatology) for the U.S.-Affiliated Pacific Islands (USAPI). Results revealed that the sea-level variations in the northwestern tropical Pacific islands (e.g. Guam and Marshall Islands) have been found to be sensitive to ENSO-cycle, with low sea-level during El Ni?o and high sea-level during La Ni?a events. The annual cycle (first harmonic) of sea-level variability in these north Pacific islands has also been found to be very strong. The composites of SST and circulation diagnostic show that strong El Ni?o years feature stronger surface westerly winds in the equatorial western/central Pacific, which causes north Pacific islands to experience lower sea-level from July to December, while the sea-level in south Pacific islands (e.g. American Samoa) remains unchanged. As the season advances, the band of westerly winds propagates towards the south central tropical Pacific and moves eastward, which causes American Samoa to experience a lower sea-level from January to June, but with six months time lag as compared to Guam and the Marshalls. U.S.-Affiliated Pacific Islands are among the most vulnerable communities to climate variability and change. This study has identified the year-to-year ENSO climate cycle to have significant impact on the sea-level variability of these islands. Therefore, regular monitoring of the ENSO climate cycle features that affect seasonal sea-level variability would provide substantial opportunities to develop advance planning and decision options regarding hazard management in these islands.     

Aspartic acid racemization in Late Wisconsin Lake Ontario sediments

We have determined aspartic acid racemization and [¹⁴C] ages in sediment from a 17-m piston core recovered from Lake Ontario. This core represents a depositional record extending back into the Late Wisconsin. Total organic radiocarbon ages of the glaciolacustrine lower section of the core are older than the true depositional age. Hence we suggest that these ages do not represent time elapsed since deposition but rather may be up to several thousand years too old due to mixing with ¹⁴C-depleted organic matter and possibly also d-amino acids contained by the glacier and deposited as the glacier receded. Further studies are suggested that might test this hypothesis as well as establish the general applicability of racemization dating to clay sediments.