Communication and health beliefs - Mass and interpersonal influences on perceptions of risk to self and others

This study investigated the impact of media coverage of a health issue (skin cancer) on judgements of risk to self and others and the role of related communication processes. Consistent with predictions derived from the impersonal impact hypothesis, the effects of mass communication were more evident in perceptions of risk to others rather than in perceptions of personal risk. Perceptions of personal risk were more strongly correlated with interpersonal communication. However, as suggested by media system dependency theory, the relationship between mass communication and beliefs was complex. The impact of mass communication on both personal and impersonal perceptions was bound to be moderated by self-reported dependence on mass mediated information. The effect of this two-way interaction 071 perceptions of personal risk was partially mediated through interpersonal communication. Results point to the interdependence of mass and interpersonal communication as sources of social influence and the role of media dependency in shaping media impact.

The English-only movement: A communication analysis of changing perceptions of language vitality

This paper reexamines the potential impact of the English-only movement on linguistic minorities and Anglos' perceptions of their own and minority groups' language vitality. Of particular interest is the Hispanic population-the fastest growing minority in the U.S. Communication scholars have paid only scant attention to the English-only movement and how it affects the social and communication climate for Latinos. However, literature reviews prepared for the American Psychological Association and for the Teachers of English to Speakers of Other Languages (in 1991 and 1995, respectively) concluded that English-only initiatives have negative consequences for limited-English proficiency groups. Revisiting this still-growing issue in the light of more recent studies across disciplines and media reports, we examine how Anglo support for English-only policies limits the use, promotion, and salience of minority languages like Spanish in institutional settings and in the linguistic landscape and suggest directions for future research.

Isolation of arboviruses from mosquitoes (Diptera : Culicidae) collected from the Gulf Plains region of northwest Queensland, Australia

As part of investigations into Japanese encephalitis (JE) virus and related flaviviruses in northern Australia, 153,529 mosquitoes were collected and processed for virus isolation from the Gulf Plains region of northwest Queensland. Collections front within 30 km of each of the townships of Croydon, Normanton and Karumba yielded 3,087 (2.0%), 66,009 (43.0%), and 84,433 (55.0%) mosquitoes, respectively, from which 16 viruses were isolated. Four isolates of Murray Valley encephalitis (MVE), two of Kunjin (KUN), three of Ross River (1111), and one of Sindbis (SIN) viruses were obtained from Culex sitiens subgroup mosquitoes. Molecular identification of the mosquito species composition of these virus positive pools revealed that most isolates were from pools containing mainly Culex annulirostris Skuse and low numbers of Cidex palpalis (Taylor). Only three pools, one each of MVE, KUN, and RR, were from mosquitoes identified exclusively as Cx. annulirostris. Other viruses isolated include one Edge Hill Virus from Ochlerotatus normanensis (Taylor), an isolate of SIN from Anopheles meraukensis Venhuis, two isolates of RR from Anopheles amictus Edwards, and single isolates of RR from Anopheles bancroftii Giles and Aedes lineatopennis (Ludlow). The isolate of RR from Ae. lineatopennis was the first reported from this species. The public health implications of these isolations in the Gulf Plains region are discussed briefly.

Cloud-point extraction and preconcentration of cyanobacterial toxins (microcystins) from natural waters using a cationic surfactant

A new cloud-point extraction and preconcentration method, using a cationic, surfactant, Aliquat-336 (tricaprylyl-methy;ammonium chloride), his-been developed for the determination of cyanobacterial toxins, microcystins, in natural waters. Sodium sulfate was used to induce phase separation at 25 degreesC. The phase behavior of Aliquat-336 with respect to concentration of Na2SO4 was studied. The cloud-point system revealed a very high phase volume ratio compared to other established systems of nonionic, anionic, and cationic surfactants: At pH 6-7, it showed an outstanding selectivity in ahalyte extraction for anionic species. Only MC-LR and MC-YR, which are known to be predominantly anionic, were extracted (with averaged recoveries of 113.9 +/- 9% and 87.1 +/- 7%, respectively). MC-RR, which is likely to be amphoteric at the above pH range, was. not cle tectable in.the extract. Coupled to HPLC/UV separation and detection, the cloud-point extraction method (with 2.5 mM Aliquat-336 and 75 mM Na2SO4 at 25 degreesC) offered detection limits of 150 +/- 7 and 470 +/- 72 pg/mL for MC-LR and MC-YR, respectively, in 25 mL of deionized water. Repeatability of the method was 7.6% for MC-LR and 7.3% for MC-YR: The cloud-point extraction process can be. completed within 10-15 min with no cleanup steps required. Applicability of the new method to the determination of microcystins in real samples was demonstrated using natural surface waters, collected from a local river and a local duck pond spiked with realistic. concentrations of microcystins. Effects of salinity and organic matter (TOC) content in the water sample on the extraction efficiency were also studied.

Observations of foehn onset in the Southern Alps, New Zealand

Local scale windfield and air mass characteristics during the onset of two foehn wind events in an alpine hydro-catchment are presented. Grounding of the topographically modified foehn was found to be dependent on daytime surface heating and topographic channelling of flow. The foehn front was observed to advance down-valley until the valley widened significantly. The foehn wind appeared to decouple from the surface downstream of the accelerated flow associated with the valley constriction. and to be lifted above local thermally generated circulations including a lake breeze. Towards evening. the foehn front retreated up valley in response to reduced surface heating and the intrusion into the study area of a deep and cool air mass associated with a regional scale mountain-plain circulation. Differences in the local windfield observed during both case study events reflect the importance of different thermal and dynamic forcings on airflow in complex terrain. These are the result of variation in surface energy exchanges, channelling and blocking of airflow. Observations presented here have both theoretical and applied implications with regard to forecasting foehn onset, wind hazard management, recreational activities and air quality management in alpine settings.

Analysis of the wind field and heat budget in an alpine lake basin during summertime fair weather conditions

Observational data collected in the Lake Tekapo hydro catchment of the Southern Alps in New Zealand are used to analyse the wind and temperature fields in the alpine lake basin during summertime fair weather conditions. Measurements from surface stations, pilot balloon and tethersonde soundings, Doppler sodar and an instrumented light aircraft provide evidence of multi-scale interacting wind systems, ranging from microscale slope winds to mesoscale coast-to-basin flows. Thermal forcing of the winds occurred due to differential heating as a consequence of orography and heterogeneous surface features, which is quantified by heat budget and pressure field analysis. The daytime vertical temperature structure was characterised by distinct layering. Features of particular interest are the formation of thermal internal boundary layers due to the lake-land discontinuity and the development of elevated mixed layers. The latter were generated by advective heating from the basin and valley sidewalls by slope winds and by a superimposed valley wind blowing from the basin over Lake Tekapo and up the tributary Godley Valley. Daytime heating in the basin and its tributary valleys caused the development of a strong horizontal temperature gradient between the basin atmosphere and that over the surrounding landscape, and hence the development of a mesoscale heat low over the basin. After noon, air from outside the basin started flowing over mountain saddles into the basin causing cooling in the lowest layers, whereas at ridge top height the horizontal air temperature gradient between inside and outside the basin continued to increase. In the early evening, a more massive intrusion of cold air caused rapid cooling and a transition to a rather uniform slightly stable stratification up to about 2000 m agl. The onset time of this rapid cooling varied about 1-2 h between observation sites and was probably triggered by the decay of up-slope winds inside the basin, which previously countered the intrusion of air over the surrounding ridges. The intrusion of air from outside the basin continued until about mid-night, when a northerly mountain wind from the Godley Valley became dominant. The results illustrate the extreme complexity that can be caused by the operation of thermal forcing processes at a wide range of spatial scales.

Being attuned to intergroup differences in mergers: The role of aligned leaders for low-status groups

The present research focused on responses of low-status group members to a merger with a high-status group. A study was conducted (N = 153) in which the alignment of the leader for the merged group (ingroup vs. outgroup) and leader behavior (equality, outgroup favoritism, ingroup favoritism, complementarity) were manipulated. The authors predicted that the leader, by his or her behavior, would play an important role in defining the new relationship between premerger groups. Overall, low-status ingroup leaders were evaluated more positively than high-status outgroup leaders. Ingroup leaders were evaluated more favorably and were more likely to engender a common identity in the merged group than were outgroup leaders when leaders behaved in an ingroup-favoring or complementary fashion. In contrast, evaluations of ingroup and outgroup leaders did not differ when the leader stressed equality or was outgroup favoring. The findings demonstrate the important role leaders can play in accentuating or de-emphasizing premerger status differences.

Development and evaluation of a species diagnostic polymerase chain reaction-restriction fragment-length polymorphism procedure for cryptic members of the Culex sitiens (Diptera : Culicidae) subgroup in Australia and the southwest Pacific

Members of the Culex sitiens subgroup are important vectors of arboviruses, including Japanese encephalitis virus, Murray Valley encephalitis virus and Ross River virus. Of the eight described species, Cx. annulirostris Skuse, Cx. sitiens Wiedemann, and Cx. palpalis Taylor appear to be the most abundant and widespread throughout northern Australia and Papua New Guinea (PNG). Recent investigations using allozymes have shown this subgroup to contain cryptic species that possess overlapping adult morphology. We report the development of a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) procedure that reliably separates these three species. This procedure utilizes the sequence variation in the ribosomal DNA ITS1 and demonstrates species-specific PCR-RFLP profiles from both colony and field collected material. Assessment of the consistency of this procedure was undertaken on mosquitoes sampled from a wide geographic area including Australia, PNG, and the Solomon Islands. Overlapping adult morphology was observed for Cx. annulirostris and Cx. palpalis in both northern Queensland and PNG and for all three species at one site in northwest Queensland.

Enhancement or modulation of the vector competence of ochlerotatus vigilax (Diptera : Culicidae) for Ross River virus by temperature

Two different doses of Ross River virus (1111) were fed to Ochlerotatus vigilax (Skuse), the primary coastal vector in Australia; and blood engorged females were held at different temperatures up to 35 d. After ingesting 10(4.3) CCID50/Mosquito, mosquitoes reared at 18 and 25degreesC (and held at the same temperature) had higher body remnant and head and salivary gland titers than those held at 32degreesC, although infection rates were comparable. At 18, 25, and 32degreesC, respectively, virus was first detected in the salivary glands on days 3, 2, and 3. Based on a previously demonstrated 98.7% concordance between salivary gland infection and transmission, the extrinsic incubation periods were estimated as 5, 4, and 3 d, respectively, for these three temperatures. When Oc. vigilax reared at 18, 25, or 32degreesC were fed a lower dosage of 10(3.3) CCID50 RR/mosquito, and assayed after 7 d extrinsic incubation at these (or combinations of these) temperatures, infection rates and titers were similar. However, by 14 d, infection rates and titers of those reared and held at 18 and 32degreesC were significantly higher and lower, respectively. However, this process was reversible when the moderate 25degreesC was involved, and intermediate infection rates and titers resulted. These data indicate that for the strains of RR and Oc. vigilax used, rearing temperature is unimportant to vector competence in the field, and that ambient temperature variations will modulate or enhance detectable infection rates only after 7 d: extrinsic incubation. Because of the short duration of extrinsic incubation, however, this will do little to influence RR epidemiology, because by this time some Oc. vigilax could be seeking their third blood meal, the latter two being infectious.

The coincidence of thrips and dispersed pollen in PNRSV-infected stonefruit orchards - a precondition for thrips-mediated transmission via infected pollen

Recent laboratory studies have demonstrated that Prunus necrotic ringspot virus (PNRSV) (family Bromoviridae) can be readily transmitted when thrips and virus-bearing pollen are placed together on to test plants. For this transmission mechanism to result in stonefruit tree infection in the field, PNRSV-bearing pollen must be deposited onto surfaces of stonefruit trees on which thrips also occur. In a previous paper, we demonstrated that almost all pollen in a PNRSV-infected Japanese plum orchard in southeastern Queensland was deposited onto flowers, whereas few grains occurred on leaves and none on stems. Here, we present results of our investigation of thrips species composition, distribution and abundance on stonefruit trees in the same study area as our previous pollen deposition study. We collected a total of 2010 adult thrips from 13 orchards during the 1989, 1991 and 1992 flowering seasons of which all but 14 were in the suborder Terebrantia. Most (97.4%) terebrantian thrips were of three species, Thrips imaginis, Thrips australis and Thrips tabaci. Thrips tabaci as well as species mixtures that included T imaginis, T australis and T tabaci have been shown to transmit PNRSV via infected pollen in laboratory tests. Adult thrips were frequently collected from flowers but rarely from leaves and never from stems. Large and significant differences in numbers of T imaginis, T australis and T tabaci adults in flowers occurred among orchards and between seasons. No factor was conclusively related to thrips numbers but flowers of late-flowering stonefruit varieties tended to hold more thrips than those of early-flowering varieties. Our results indicate that the common thrips species present on stonefruit trees in the Granite Belt are also ones previously shown to transmit PNRSV via infected pollen in the laboratory and that these thrips are concentrated in stonefruit flowers where most stonefruit pollen is deposited. These results contribute to mounting circumstantial evidence that stonefruit flowers may be inoculated with PNRSV via an interaction of thrips with virus-bearing pollen and that this transmission mechanism may be an important cause of new tree infections in the field.

DNA vaccine coding for the full-length infectious Kunjin virus RNA protects mice against the New York strain of West Nile virus

A plasmid DNA directing transcription of the infectious full-length RNA genome of Kunjin (KUN) virus in vivo from a mammalian expression promoter was used to vaccinate mice intramuscularly. The KUN viral cDNA encoded in the plasmid contained the mutation in the NS1 protein (Pro-250 to Leu) previously shown to attenuate KUN virus in weanling mice. KUN virus was isolated from the blood of immunized mice 3-4 days after DNA inoculation, demonstrating that infectious RNA was being transcribed in vivo; however, no symptoms of virus-induced disease were observed. By 19 days postimmunization, neutralizing antibody was detected in the serum of immunized animals. On challenge with lethal doses of the virulent New York strain of West Nile (WN) or wild-type KUN virus intracerebrally or intraperitoneally, mice immunized with as little as 0.1-1 mug of KUN plasmid DNA were solidly protected against disease. This finding correlated with neutralization data in vitro showing that serum from KUN DNA-immunized mice neutralized KUN and WN,viruses with similar efficiencies. The results demonstrate that delivery of an attenuated but replicating KUN virus via a plasmid DNA vector may provide an effective vaccination strategy against virulent strains of WN virus.

Cross-protective and Infection-Enhancing Immunity in Mice Vaccinated Against Flaviviruses Belonging to the Japanese Encephalitis Virus Serocomplex

The Japanese encephalitis virus serocomplex is a group of mosquito-borne flaviviruses that cause severe encephalitic disease in humans. The recent emergence of several members of this serocomplex in geographic regions where other closely related flaviviruses are endemic has raised urgent human health issues. Thus, the impact of vaccination against one of these neurotropic virus on the outcome of infection with a second, serologically related virus is unknown. We show here that immunity against Murray Valley encephalitis virus in vaccinated mice can cross-protect but also augment disease severity following challenge with Japanese encephalitis virus. Immunepotentiation of heterologous flavivirus disease was apparent in animals immunized with a 'killed' virus preparation when humoral antiviral immunty of low magnitude was elicited. (C) 2002 Elsevier Science Ltd. All rights reserved.

Vector competence of Australian mosquitoes (Diptera : Culicidae) for Japanese encephalitis virus

Australian mosquitoes were evaluated for their ability to become infected with and transmit a Torres Strait strain of Japanese encephalitis virus. Mosquitoes, which were obtained from either laboratory colonies and collected using Centers for Disease Control and Prevention light traps baited with CO2 and octenol or reared from larvae, were infected by feeding on a blood/sucrose solution containing 10(4.5+/-0.1) porcine stable-equine kidney (PS-EK) tissue culture infectious dose(50)/ mosquito of the TS3306 virus strain. After 14 d, infection and transmission rates of 100% and 81%, respectively, were obtained for a southeast Queensland strain of Culex annulirostris Skuse, and 93% and 61%, respectively, for a far north Queensland strain. After 13 or more days, infection and transmission rates of > 90% and greater than or equal to 50%, respectively, were obtained for southeast Queensland strains of Culex sitiens Wiedemann and Culex quinquefasciatus Say, and a far north Queensland strain of Culex gelidus Theobald. Although infection rates were > 55%, only 17% of Ochlerotatus vigilax (Skuse) and no Cx. quinquefasciatus, collected from far north Queensland, transmitted virus. North Queensland strains of Aedes aegypti L., Ochlerotatus kochi (Donitz), and Verrallina funerea (Theobald) were relatively refractory to infection. Vertical transmission was not detected among 673 F, progeny of Oc. vigilax. Results of the current vector competence study, coupled with high field isolation rates, host feeding patterns and widespread distribution, confirm the status of Cx. annulirostris as the major vector of Japanese encephalitis virus in northern Australia. The relative roles of other species in potential Japanese encephalitis virus transmission cycles in northern Australia are discussed.

Mosquito host-feeding patterns and implications for Japanese encephalitis virus transmission in northern Australia and Papua New Guinea

Japanese encephalitis (JE) virus spread to northern Australia during the 1990s, transmitted by Culex annulirostris Skuse and other mosquitoes (Diptera: Culicidae). To determine the relative importance of various hosts for potential vectors of JE virus, we investigated the host-feeding patterns of mosquitoes in northern Australia and Western Province of Papua New Guinea, with particular attention to pigs, Sus scrofa L. - the main amplifying host of JE virus in South-east Asia. Mosquitoes were collected by CDC light traps baited with dry ice and 1-octen-3-ol, run 16.00-08.00 hours, mostly set away from human habitations, if possible in places frequented by feral pigs. Bloodmeals of 2569 mosquitoes, representing 15 species, were identified by gel diffusion assay. All species had fed mostly on mammals: only 30%) were trapped where domestic pigs were kept close to human habitation. From seven of eight locations on the Australian mainland, the majority of Cx. annulirostris had obtained their bloodmeals from marsupials, probably the Agile wallaby Macropus agilis (Gould). Overall proportions of mosquito bloodmeals identified as marsupial were 60% from the Gulf Plains region of Australia, 78% from the Cape York Peninsula and 64% from the Daru area of Papua New Guinea. Thus, despite the abundance of feral pigs in northern Australia, our findings suggest that marsupials divert host-seeking Cx. annulirostris away from pigs. As marsupials are poor JE virus hosts, the prevalence of marsupials may impede the establishment of JE virus in Australia.