Intracellular bacteria associated with the ascidian<Emphasis Type="Italic"> Ecteinascidia turbinata</Emphasis>: phylogenetic and in situ hybridisation analysis

The ascidian Ecteinascidia turbinata (Herdman) is a colonial sea squirt found in the Caribbean and Mediterranean Seas. In the present study, the bacterial complement of E. turbinata has been assessed by 16S rRNA gene analysis and the most commonly occurring strains identified by restriction fragment length polymorphism. Three strains were found to predominate using this approach, with one representing >50% of clones from both larval and adult material. The 16S rRNA gene sequence of the most commonly occurring strain did not match with any known bacterial sequences and could only be assigned to the γ-proteobacteria subdivision. The two other frequently occurring strains were assigned to the Mollicutes. In situ hybridisation analysis with eubacterial probes to 16S rRNA revealed the presence of apparently endosymbiotic bacteria in adult and larval tissue, and electron microscopy confirmed the presence of putative bacteriocytes in the larval tissue. The presence of the same bacteria in the brooded larvae suggested that they were vertically transmitted from parent to offspring. Further hybridisation using a novel probe designed to be specific to the 16S rRNA sequence of the dominant strain, highlighted the same cell types as that revealed by the eubacterial probe. The results suggest that the bacteria represent a novel strain, denoted "Candidatus Endoecteinascidia frumentensis", and that they may have an important role in the biology of E. turbinata.     

SOME SIMPLE MODELS FOR DISCRETE VARIATE TIME SERIES1

ABSTRACT: Simple models are presented for use in the modeling and generation of sequences of dependent discrete random variables. The models are essentially Markov Chains, but are structurally autoregressions, and so depend on only a few parameters. The marginal distribution is an intrinsic component in the specification of each model, and the Poisson, Geometric, Negative Binomial and Binomial distributions are considered. Details are also given for the introduction of time-dependence into the means of the sequences so that seaonality can be treated simply.     

Access and Local Government Research: Methodological Reflections

This methodological paper draws on research from Australia to examine the question of gaining access to local governments in undertaking work on natural resource management. It is argued that a range of macro-level changes have impacted on the local government sector in Australia, and these changes have rendered access problematic for researchers. These changes include an expansion of local government roles, an increase in financial pressure within the sector, a proliferation of audit measures across local governments and a low level of respect amongst local government personnel for academics and academic work. The paper concludes by identifying the reasons why understanding access in qualitative research on local government and environmental sustainability is important.     

Development of a personal exposure monitor for two sizes of inhalable particulates

Measurement of personal exposure to ambient level particulate concentrations is often extremely difficult because of a lack of personal exposure monitors capable of collecting measurable quantities within a meaningful sampling period. A new personal exposure monitor for two fractions of inhalable particulates (i.e., the 3–15 μm aerodynamic diameter and the < 3 μm or respirable fraction) has been developed and characterized. This monitor is capable of collecting a sample of each fraction that is quantifiable with ambient concentrations of inhalable/respirable particulates as low as 25 μg/m³ in a 24-h sampling period. Wind tunnel tests have been made on the particulate personal exposure monitor to determine sampling efficiency as a function of relative wind speed and orientation with respect to the sampler.     

Concentrations and patterns of organic contaminants in Atlantic white-sided dolphins (Lagenorhynchus acutus) from Irish and Scottish coastal waters

Chlorobiphenyls (CBs) and organochlorine pesticides (OCPs) have been determined in the blubber of 17 Atlantic white-sided dolphins stranded at Killala Bay, Co Mayo, Ireland and five from the Scottish coast. The concentrations of the contaminants measured range from 773 to 63,400 microg kg(-1) for sigmaCB and from 160 to 54,600 microg kg(-1) for sigmaDDT. The concentrations of the CBs and OCPs is highly dependent on the age, sex, reproductive state and nutritional condition of the animals in addition to the intake via the food web. Principal Components Analysis (PCA) has been used to study the variation of chemical patterns (data ratioed to CB 153). Immature animals (< 6 years), mature males and primogravid females, and lactating females could be distinguished on the basis of their contaminant patterns. This paper describes the different processes of bioaccumulation and metabolism of organochlorine contaminants (OCs) in this species.     

Multi-bioassay approach for assessing the potency of complex mixtures of polycyclic aromatic hydrocarbons

The chick embryotoxicity screening test (CHEST) and the Salmonella/microsome bioassay were used to evaluate embryotoxic and mutagenic endpoints from crude coal tar (CT) and its fractionated polycyclic aromatic hydrocarbon (PAH) mixtures (designated as A, B, C, D and E). In the CHEST assay, CT and PAH mixtures were injected into the egg yolk. A dose-dependent increase in embryo mortality was observed for all fractions. The E fraction resulted in 47% embryo mortality at a dose of 0.125 mg/kg and was more toxic than CT. At a dose of 1 mg/kg, 85-100% embryonic deaths occurred in fractions C and D and these two fractions were more potent than fractions A and B. The main visual toxic manifestations were liver lesions, discoloration of the liver, and edema. Both CT and fractionated PAH mixtures were also tested in the Salmonella/microsome plate incorporation assay with Salmonella typhimurium strain TA98 and were evaluated with and without metabolic activation at five dose levels. In the presence of S9, the CT and fractions C, D and E induced a dose-dependent positive response. Results from the Salmonella/microsome assay were in good agreement with findings from the CHEST assay suggesting that these two bioassays in combination may facilitate the rapid detection and ranking of complex PAH mixtures.     

Evaluation of guardrail systems for preventing falls through roof and floor holes

Introduction

Fall-related occupational injuries and fatalities are serious problems in the U.S. construction industry, especially incidents related to unguarded holes. The National Institute for Occupational Safety and Health, Division of Safety Research, Morgantown, WV conducted a project to evaluate the effectiveness of guardrail systems to prevent falls through roof and floor holes.

Methods

Two commercial edge-protection products were evaluated when used as perimeter guarding around a roof hole. Installations of the commercial products were compared to job-built guardrails constructed of 2^″ × 4^″ construction-grade lumber. Occupational Safety and Health Administration (OSHA) regulations require that “a force of at least 200 pounds” must be supported by the top rail of a guardrail system “in any outward or downward direction at any point along the top edge.” A laboratory testing system was developed to evaluate this requirement. A dynamic 200-lb force was generated against the top rail using a weighted manikin mounted on a hinged steel frame. Nine construction workers, who served as test subjects, each built five different guardrail configurations.

Results

All 45 configurations met the 200-lb OSHA requirement. Installation time for one commercial product was 32% quicker than the job-built configuration (25.6 min vs. 37.9 min).

Impact on Industry

This study: (a) indicates that the two edge-protection products can be used as perimeter guarding; (b) highlights the importance of using proper materials and fasteners to construct guardrails to protect workers from falling into unguarded roof and floor holes; and (c) discusses an overall-strength-testing methodology that can be used by fall-protection researchers.     

Photocatalytic degradation of Chicago Sky Blue 6B and Benzopurpurin 4B using titanium dioxide thin film

Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are： Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such as NO3^- and SO4^2-. Chemical oxygen demand（COD） measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions reauired Iona dearadation time.     

Reconciling competing values placed upon goose populations: The evolution of and experiences from the Islay Sustainable Goose Management Strategy

The Scottish island of Islay hosts 45 000 barnacle geese Branta leucopsis (56% of the Greenland barnacle goose population, plus those passing through on migration), 5000 Greenland white-fronted geese Anser albifrons flavirostris (up to 30% of the world population) and 2500 greylag geese Anser anser, most of which feed on 9000 ha of grassland. The financial impacts of estimated agricultural damage have risen greatly over the past 20 years due to increasing goose numbers and higher farming costs. Mechanisms implemented to resolve conflict over time are reviewed for their effectiveness. Emphasis is placed on coordinating the implementation of strategic national conflict resolution at a local scale where the relative pressure from internationally important concentrations of geese on agriculture is acute. Despite the “local” nature of this problem, the benefit from the experience of decades of attempted conflict resolution and the effectiveness of existing programmes can contribute much to the regional and flyway dimensions of this international issue.     

The 2004 tsunami and mental health in Thailand: a longitudinal analysis of one‐and two‐year post‐disaster data

Some 280,000 people died in the Indian Ocean tsunami on 26 December 2004. This cohort study examined its impact on mental health one and two years later. It did so by investigating the association between six consequent variables (personal injury, loss of home, loss of business, death of a family member, injury to a family member, or loss of a family member's business) and mental health, as measured by the 36‐item Short Form Health Survey (SF‐36), among residents in four provinces of Thailand. One year later, participants who suffered a personal injury, the loss of a business, or the loss of a family member reported poorer mental health than those who were unaffected. Two years later, participants who experienced the loss of a family member reported poorer mental health than those who were unaffected. This research shows that such a disaster may have long‐lasting ramifications for mental health, and that diverse losses may influence mental health differently.