Theoretical and spatial limits to the value of rural environmental benefits: Evidence from the forestry sector

The valuation of environmental benefits has been well researched in the forestry sector. This is not generally the case in the agriculture sector although schemes to compensate farmers for provision of officially defined environmental benefits are already in place throughout the European Union. This paper draws on empirical findings from forestry and deductions from economic theory to challenge the notion of the universality of such benefits. Empirical findings from forestry suggest recreational use value is location specific rather than widely spread. Household utility theory predicts zero willingness to pay to maintain the status quo level of a previously unpaid for environmental benefit (when provision is not perceived as under risk) but a positive willingness to pay for an increase. Thus, non use values cannot be attributed to the major part of existing commercial forestry area but to spatially restricted schemes such as additional afforestation or preservation of ancient natural woodlands.

The adaptive value of polyembryony.

From an evolutionary standpoint, the production of offspring is the single most important aspect of an animal's life. Offspring carry an individual's genes into the next generation and it is the differential representation of genes in a population that drives evolutionary change. There are a variety of ways in which animals create offspring, ranging from cases where parents make identical copies of themselves by budding or parthenogenesis, to the standard case in vertebrates where gametes from a male and female fuse in sexual reproduction to produce the next generation. In this article we describe an usual variant of sexual reproduction, polyembryony.

Can diagnostic triage by general practitioners or rheumatology nurses improve the positive predictive value of referrals to early arthritis clinics?

Objectives: To determine whether diagnostic triage by general practitioners (GPs) or rheumatology nurses (RNs) can improve the positive predictive value of referrals to early arthritis clinics (EACs).

Methods: Four GPs and two RNs were trained in the assessment of early in?ammatory arthritis (IA) by four visits to an EAC supervised by hospital rheumatologists. Patients referred to one of three EACs were recruited for study and assessed independently by a GP, an RN and one of six rheumatologists. Each assessor was asked to record their clinical ?ndings and whether they considered the patient to have IA. Each was then asked to judge the appropriateness of the referral according to predetermined guidelines. The rheumatologists had been shown previously to have a satisfactory level of agreement in the assessment of IA.

Results: Ninety-six patients were approached and all consented to take part in the study. In 49 cases (51%), the rheumatologist judged that the patient had IA and that the referral was appropriate. The assessments of GPs and RNs were compared with those of the rheumatologists. Levels of agreement were measured using the kappa value, where 1.0 represents total unanimity. The kappa value was
0.77 for the GPs when compared with the rheumatologists and 0.79 for the RNs. Signi?cant stiffness in the morning or after rest and objective joint swelling were the most important clinical features enabling the GPs and RNs to discriminate between IA and non-IA conditions.

Conclusion: Diagnostic triage by GPs or RNs improved the positive predictive value of referrals to an EAC with a degree of accuracy approaching that of a group of experienced rheumatologists.

Gazing at Ground Zero: Tourism, Voyeurism and Spectacle

This essay uses the temporary viewing platform at the site of the former World Trade Center to explore our fascination with violence, conflict and disaster. It illustrates how discourses of voyeurism and authenticity promote a desire for sites of horror, and examines how that desire both disrupts and reinforces our prevailing interpretations of global politics. The viewing platform at Ground Zero was initially constructed to manage the thousands of people who traveled to New York in response to the shocking media images of 11 September. However, their desire to escape mediation and touch "the real" had the opposite effect - it transformed Ground Zero into a tourist attraction. Using Ground Zero as a starting point, this essay theorizes discourses of voyeurism and authenticity through the work of Baudrillard, Debord and Bauman in an effort to position the tourist as a significant political subject.

Mineralogical characteristics and transformations during long-term operation of a zero-valent iron reactive barrier

Received for publication October 31, 2002. Design and operation of Fe0 permeable reactive barriers (PRBs) can be improved by understanding the long-term mineralogical transformations that occur within PRBs. Changes in mineral precipitates, cementation, and corrosion of Fe0 filings within an in situ pilot-scale PRB were examined after the first 30 months of operation and compared with results of a previous study of the PRB conducted 15 months earlier using X-ray diffraction and scanning electron microscopy employing energy dispersive X-ray and backscatter electron analyses. Iron (oxy)hydroxides, aragonite, and maghemite and/or magnetite occurred throughout the cores collected 30 mo after installation. Goethite, lepidocrocite, mackinawite, aragonite, calcite, and siderite were associated with oxidized and cemented areas, while green rusts were detected in more reduced zones. Basic differences from our last detailed investigation include (i) mackinawite crystallized from amorphous FeS, (ii) aragonite transformed into calcite, (iii) akaganeite transformed to goethite and lepidocrocite, (iv) iron (oxy)hydroxides and calcium and iron carbonate minerals increased, (v) cementation was greater in the more recent study, and (vi) oxidation, corrosion, and disintegration of Fe0 filings were greater, especially in cemented areas, in the more recent study. If the degree of corrosion and cementation that was observed from 15 to 30 mo after installation continues, certain portions of the PRB (i.e., up-gradient entrance of the ground water to the Fe0 section of the PRB) may last less than five more years, thus reducing the effectiveness of the PRB to mitigate contaminants. Abbreviations: EDX, energy dispersive X-ray • Fe0, zerovalent iron • PRB, permeable reactive barrier • SEM, scanning electron microscopy • XRD, X-ray diffraction