Measurement of nuclear transparency for the A(e,e'pi+) reaction

We have measured the nuclear transparency of the A(e,e'pi+) process in 2H, 12C, 27Al, 63Cu, and 197Au targets. These measurements were performed at the Jefferson Laboratory over a four momentum transfer squared range Q2=1.1 to 4.7 (GeV/c)2. The nuclear transparency was extracted as the super-ratio of (sigmaA/sigmaH) from data to a model of pion-electroproduction from nuclei without pi-N final-state interactions. The Q2 and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.

Supporting rural carers through telehealth

INTRODUCTION

Videoconferencing is now a firmly established feature of rural health care in Australia. However, the health sector has not used videoconferencing extensively outside the provision of clinical care. This article describes a program of education and support to rural carers via videoconferencing which demonstrates its potential in promoting health.

METHODS

Semi-structured interviews were conducted with six service providers, eight carers who participated in sessions and the facilitator of the sessions. Attendance and financial records augmented the interview data.

RESULTS

Videoconferencing was well accepted by carers and the facilitator. Carers reported having a positive interaction with the facilitator and other participants despite being at a distance, and the facilitator found the technology offered her more ways to observe non-verbal cues discretely. Carers demonstrated that they had retained information provided and that they had made small behaviour changes. They credited the success to sharing experiences with peers. Local providers of aged care services stressed that the sessions offered a service that they, who were employed to be 'problem-solvers', were not able to perform but that as a result of the sessions they could target services more effectively. Videoconferenced sessions were 16% and 47% of the cost of a face-to-face session.

CONCLUSIONS

This study demonstrates that videoconferencing can be used to provide psychosocial support and training to groups of isolated carers. The critical element of this program was that local services were augmented and enhanced through the use of a facilitator who brought skills that were not available locally.

Estimating farmworker population size in New York State using a minimum labor demand method

Assessment of health needs and services for hand-harvest farmworkers requires reliable population estimates. In New York State, the only publicly available source for these is the Department of Labor (DOL). However, published production data exist that may enable estimation of minimum labor demand (MLD) for hand-harvest labor. Our objective was to develop an estimation process for minimum labor demand (MLD) for hand-harvested crops in NYS and contrast the results with DOL estimates. Four crop strata (below ground, ground, bush/vine, and orchard) were identified. MLD (measured in worker-seasons) was estimated by dividing the total annual harvest hours required for each crop stratum by the total hours worked by one worker in a season for that crop stratum. The MLD estimate of the total number of worker seasons combined for all strata (14,121) was higher than that of the DOL (8,230). Harvest acreage was unavailable for 21% of the 991 county-crop combinations studied; therefore, data were imputed from other sources. Within these strata, the greatest difference was found for ground crops, where the DOL count was 28% of the size of the MLD estimate. DOL and MLD estimates were closest in orchard crops (DOL 109% of MLD). Publicly available data provide a potentially valuable source of informationfor estimation of the MLD. Use of these methods implies that the DOL may substantially underestimate the size of this population. Differences seen between the two methods were sensitive to the crop type. County-level farm surveys to verify MLD estimation factors would enhance the method's accuracy.

Phylogeographic analysis of mitochondrial gene flow and introgression in the salamander, Plethodon shermani

Plethodon shermani comprises a series of geographically disjunct populations occupying high-elevation mountain isolates. These populations hybridize at their borders with salamanders of the Plethodon glutinosus species complex, and past range expansions inferred from Pleistocene climatic cycles may have increased the possible genetic interactions between P. shermani and species of the P. glutinosus complex. Because mitochondrial DNA haplotypes often show introgression across species borders, we survey mtDNA variation for evidence of past and ongoing genetic interactions between P. shermani, its close relative Plethodon cheoah, and species of the P. glutinosus complex. Ongoing hybridization with the P. glutinosus-complex species Plethodon teyahalee is accompanied by extensive mitochondrial introgression in some Unicoi populations of P. shermani, but it has little genetic impact on P. shermani populations outside hybrid zones at three other isolates (Tusquitee, Wayah Bald, Standing Indian). Some Unicoi populations of P. shermani exhibit mtDNA evidence of past hybridization with diverse lineages from P. aureolus and P. glutinosus. The Tusquitee isolate of P. shermani is also characterized by mtDNA haplotypes most closely related to Plethodon aureolus and P. glutinosus, presumably introduced by past genetic contact with these species or with introgressed populations of Unicoi P. shermani. The mtDNA variation in sampled populations of the Wayah Bald and Standing Indian isolates of P. shermani appears largely unaffected by ongoing hybridization. Principal components analyses of allozymic data indicate that P. shermani isolates collectively form a genetically homogeneous unit clearly demarcated from species with which they have had current or past genetic interactions. Rapid mtDNA introgression associated with transient contacts between P. shermani and other species permits a fine-level resolution of evolutionary lineages not evident from allozymic data.

Implementation of the Australian core public health functions in rural Western Australia

OBJECTIVE

To assess the implementation of the Australian core functions of public health in rural Western Australia.

METHODS

Cross-sectional surveys (n=26) and semi-structured key informant interviews (n=64) with public health practitioners throughout each of the eight rural health regions in Western Australia. A scoring system was utilised to categorise responses that were frequently part of current practice (score=2), sometimes undertaken (score=1) and rare or not undertaken at all (score=0).

RESULTS

Functions with reasonably good coverage (mean score 1.0) included: preventing and controlling communicable and non-communicable diseases; promoting and supporting healthy lifestyles; planning, funding, managing and evaluating health gain; ensuring safe and healthy environments; and contributing to healthy growth and development through all life stages. Lower levels of coverage were found for: assessing health needs; developing healthy public policy and fiscal measures; strengthening communities; and improving health for Aboriginal people and other vulnerable groups.

CONCLUSIONS

There are limitations in the capacity of the rural public health workforce in Western Australia to implement the core public health functions. While some areas were defined as being adequately addressed, gaps in implementation appeared across all nine functions.

IMPLICATIONS

The Australian core functions can be utilised to broadly assess current public health practice, however further development of the functions and their measurement, plus methods to align accountability measures for current public health practice with the core functions, are required.

Edentulism and associated factors in people 60 years and over from urban, rural and remote Western Australia

BACKGROUND

Edentulism is declining in the aged, in turn increasing demand on dental services. The aim of this study was to describe the pattern of edentulism and associated factors for people 60 years or over in urban, rural and remote Western Australia.

METHODS

A cross-sectional telephone interview survey was conducted of 2100 people aged 60 years or over (urban n=800, rural n=800, remote n=500), identified through the State Electoral Roll, who were living in non-institutionalized accommodation in Western Australia and who were able to speak English sufficiently well to be interviewed in English.

RESULTS

The main outcome measure was edentulism. The prevalence of edentulism was 25 per cent for people in urban areas, 34 per cent for people in rural areas and 32 per cent for people in remote areas. Respondents aged 60-69 years had less than half the edentulism than respondents aged 80 years or over. Multivariable logistic regression models showed geographic location, age, gender, education and occupation were significantly associated with edentulism.

CONCLUSIONS

The percentage of edentulism was highest in rural areas with some clear demographic trends. These future aged cohorts are likely to follow the same patterns of social and geographic disadvantage as found for the current edentate cohort. The results were consistent with other studies while providing state level multivariate results to assist service planning.

A molecular phylogenetic study of ecological diversification in the Australian lizard genus Ctenophorus

We present phylogenetic analyses of the lizard genus Ctenophorus using 1,639 aligned positions of mitochondrial DNA sequences containing 799 parsimony-informative characters for samples of 22 species of Ctenophorus and 12 additional Australian agamid genera. Sequences from three protein-coding genes (ND1, ND2, and COI) and eight intervening tRNA genes are examined using both parsimony and maximum-likelihood analyses. Species of Ctenophorus form a monophyletic group with Rankinia adelaidensis, which we suggest placing in Ctenophorus. Ecological differentiation among species of Ctenophorus is most evident in the kinds of habitats used for shelter. Phylogenetic analyses suggest that the ancestral condition is to use burrows for shelter, and that habits of sheltering in rocks and shrubs/hummock grasses represent separately derived conditions. Ctenophorus appears to have undergone extensive cladogenesis approximately 10-12 million years ago, with all three major ecological modes being established at that time.

A molecular phylogenetic analysis of diversification in Amazonian Anolis lizards

We present a mitochondrial DNA (mtDNA) haplotype phylogeny for Amazonian Anolis lizards, including geographical sampling within four species distributed across the Amazon basin (A. fuscoauratus, A. nitens, A. ortonii and A. punctatus). Approximately 1500 bp of mtDNA encoding ND2, COI and four transfer RNAs (tRNAs) are reported for 39 specimens representing four to five populations of each widespread species, plus eight outgroups. These new sequences are aligned with eight previously published sequences, yielding 914 variable characters and 780 parsimony-informative characters. Phylogenetic analyses using maximum parsimony and maximum likelihood reject the hypothesis that Amazonian anoles form a monophyletic group excluding Central American and Caribbean anoles, and suggest multiple faunal exchanges among these regions. Haplotype divergence among geographical populations of A. nitens, whose variation was influential in formulating the Pleistocene refuge hypothesis of Amazonian speciation, is very large (13-22% sequence difference), suggesting that these populations separated well before the Pleistocene. Haplotype divergences among geographical populations of A. fuscoauratus (3-4%), A. punctatus (4-9%) and A. ortonii (6-8%) also indicate pre-Pleistocene differentiation within each species, but temporally incongruent patterns among species.

The effect of botulinum toxin type A and a variable hip abduction orthosis on gross motor function: a randomized controlled trial

Hip displacement is the second most common deformity after equinus in children with cerebral palsy (CP), and may result in dislocation, pain, fixed deformity and loss of function. We studied the combined effects of intramuscular injections of botulinum toxin type A (BTX-A) to the adductors and hamstrings and a variable hip abduction orthosis (SWASH), on gross motor function, hip displacement and progression to surgery, in a randomized clinical trial. Thirty-nine children, with bilateral spastic cerebral palsy, and mean age 3 years + 2 months (range 1 year+7 months--4 years +10 months) entered the trial. Gross Motor Function Classification System (GMFCS) levels were as follows: one child was level II, 11 were level III, 13 were level IV and 14 were level V. After concealed randomization, 20 were allocated to the control group and 19 to the intervention group. Thirty-five children completed the follow up at 1 year. The novel intervention group received up to 4.0 U BOTOX/kg/muscle, 16 U/kg/body weight every 6 months plus the use of a SWASH brace. The control group received clinical best practice comprising physiotherapy but no hip abduction bracing. Both groups showed improvements in total Gross Motor Function Measure (GMFM) score [mean 6.0% BTX-A group; 6.1% Control; 95% CI -- 6.7, 6.5 (NS)], however, there was no additional treatment effect for the study group. There were similar improvements on GMFM goal scores and GMFM-66 scores, but again no additional treatment effect was observed. Multiple regression of change in total GMFM by GMFCS classification for each group showed greater improvement in the total scores from baseline in the BTX-A/SWASH treated group than the control group. In the first year, nine children (two in the intervention group and seven in the control group) required soft tissue surgery because of progressive hip migration in excess of 40%. A longer-term follow up of a larger cohort may be required to determine the effect of the combined treatment on hip displacement.

Molecular phylogenetics of western North American frogs of the Rana boylii species group

Phylogenetic relationships among frogs of the genus Rana from western North America are investigated using 2013 aligned bases of mitochondrial DNA sequence from the genes encoding ND1 (subunit one of NADH dehydrogenase), tRNA(Ile), tRNA(Gln), tRNA(Met), ND2, tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys), tRNA(Tyr), and COI (subunit I of cytochrome c oxidase), plus the origin for light-strand replication (O(L)) between the tRNA(Asn) and tRNA(Cys) genes. The aligned sequences contain 401 phylogenetically informative characters. A well-resolved phylogenetic hypothesis in which the Rana boylii species group (R. aurora, R. boylii, R. cascadae, R. muscosa, and R. pretiosa) is monophyletic is obtained. Molecular sequence divergence suggests that the R. boylii species group is approximately 8 million years old. The traditional hypothesis showing monophyly of the yellow-legged frogs (R. boylii and R. muscosa) is statistically rejected in favor of a hypothesis in which R. aurora, R. cascadae, and R. muscosa form a clade. Reanalyses of published nuclear ribosomal DNA restriction-site data and allozymic data support a monophyletic R. boylii group, but do not effectively resolve relationships among species within this group. Eight populations of R. muscosa form two major clades separated by a biogeographic break in the Sierra Nevada of California. This biogeographic break is broadly concordant with breaks found in four other amphibian and reptilian taxa. The two major clades within R. muscosa are estimated to have diverged approximately 2.2 million years before present. Each of these major clades contains two subgroups showing approximately 1.5 million years divergence, implicating climatic effects of Pleistocene glaciation in vicariance. The four distinct subgroups of R. muscosa separated by at least 1.4 million years of evolutionary divergence are suggested as potential units for conservation.

High remission rate in acute myeloblastic leukemia with only two days of chemotherapy

Twenty five patients with AML who had neither a history of toxic exposure or myelodysplasia were treated with a remission induction regimen consisting of two pulses of chemotherapy separated by 96 hrs. Each pulse consisted of cytarabine 2gm/m(2) (at t=0 and t=12 hrs) with mitoxantrone [30mg/m(2) ] administered immediately after the second cytarabine administration. Amifostine was administered three times a week [on Monday, Wednesday, and Friday] until the outcome of therapy was known. This regimen induced complete remissions in 15 of 17 patients less than 70 years of age and in 5 of 8 patients older than 70 years.

In vivo effects of IL-4, IL-10, and amifostine on cytokine production in patients with acute myelogenous leukemia

Both IL-4 and IL-10 have been shown in vitro to inhibit leukemia cell secretion of IL-1beta, GM-CSF, and TNFalpha, and increase leukemia cell release of IL-1ra. In this study, we have investigated the in vivo effects of IL-4, IL-10, and amifostine on cytokine production in patients with acute myelogenous leukemia (AML). Serum IL-1ra, IL-1beta, TNFalpha, GM-CSF, and SCF levels were measured in AML patients who received IL-4, IL-10, or amifostine. No significant changes in the serum levels of IL-1ra, IL-1beta, TNFalpha, GM-CSF, and SCF were found in AML patients who received amifostine. Both IL-4 and IL-10 were found to increase serum IL-1ra. This data is in accord with the in vitro studies. However, IL-4 increased serum GM-CSF levels and IL-10 increased serum IL-1beta and TNFalpha levels. These in vivo effects of the two cytokines differ from their in vitro effects. Despite the similar effects of IL-4 and IL-10 on cytokine production by AML cells in vitro, different effects were observed in AML patients in vivo. IL-4 increased serum SCF levels, whereas IL-10 decreased serum SCF levels. IL-4 increased serum GM-CSF levels, whereas IL-10 had no effect on them. Although IL-10 increased serum IL-1beta and TNFalpha levels, IL-4 had no effect on them. These findings indicate that the in vitro effects of IL-4 and IL-10 do not necessarily reflect their in vivo effects, and that the complex effects of the two cytokines on serum cytokine levels make it difficult to predict their therapeutic potential.

Molecular phylogenetics and historical biogeography among salamandrids of the "true" salamander clade: rapid branching of numerous highly divergent lineages in Mertensiella luschani associated with the rise of Anatolia

Phylogenetic relationships among salamandrids of the "true" salamander clade are investigated using 2019 aligned base positions (713 parsimony informative) of 20 mitochondrial DNA sequences from the genes encoding ND1 (subunit one of NADH dehydrogenase), tRNA(Ile), tRNA(Gln), tRNA(Met), ND2, tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys), tRNA(Tyr), and COI (subunit I of cytochrome c oxidase), plus the origin for light-strand replication (O(L)) between the tRNA(Asn) and the tRNA(Cys) genes. Parsimony analysis produces a robust phylogenetic estimate for the relationships of the major groups of "true" salamanders. Strong support is provided for the sister taxon relationship of Chioglossa and Mertensiella caucasica and for the placement of Salamandra and Mertensiella luschani as sister taxa. These relationships suggest two vicariant events between Europe and Anatolia caused by the formation of seaways in the Mediterranean Basin. Molecular divergence indicates an Early Miocene separation of Chioglossa and M. caucasica and a Late Miocene separation of Salamandra and M. luschani. The traditional phylogenetic hypothesis of a monophyletic Mertensiella is statistically rejected, indicating that southwestern and northeastern Anatolian populations have separate historical biogeographic origins. Therefore, we recommend placement of M. luschani in the genus Salamandra. Within M. luschani, six highly divergent lineages showing 7.6 to 10.1% pairwise sequence divergence are identified. Tests using four-taxon subsamples suggest that these lineages diverged nearly simultaneously in the Late Miocene, approximately 6 to 8 million years ago, when extensive uplifting of Anatolia occurred in response to the Arabian collision.

Identification of mRNAs expressed in tumor-infiltrating lymphocytes by a strategy for rapid and high throughput screening

Most gene expression methods often involve cumbersome steps or use expensive facilities. Additionally, some of the techniques, such as cDNA biochip, cannot define the sub-population of tissue from which the amplified cDNA was made. Here we present a rapid and high throughput screening method for analyzing the pattern of gene expression of tumor-infiltrating lymphocyte (TIL), which can minimize manipulations in cloned DNA sequencing and in bioinformatics. The pattern of TIL gene expression was studied in one ovarian cancer and one liver cancer. Our results have demonstrated that TILs have three different gene expression profiles: the first set of genes is involved in cell proliferation and mitogenic stimulation, such as c-myc and IL-8, LD78, MIP-1beta, insulin-induced protein and AH-receptor; the second set of genes includes those involved in attachment of lymphocytes to endothelium and extravasation into tumor tissues such as P-selectin ligand and integrin; and the third set, which includes genes such as the perforin, FAS ligand and granzyme B, is related to cytotoxic function to tumor cells. The patterns of TIL gene expression obtained from two specimens are marginally different and can be used in explaining the basis of molecular mechanisms regulating cellular interactions and cytotoxicity.

Chronic hepatitis C: common questions, practical answers

BACKGROUND

The hepatitis C virus (HCV) is the most common cause of chronic liver disease in the United States. Dramatic advances have been made recently in the treatment of this potentially life-threatening infection by using a combination interferon and ribavirin therapy.

METHODS

The most common questions regarding chronic HCV infections that occur in the course of clinical practice of primary care physicians were elicited through e-mail and telephone interviews. To answer these questions, computerized literature searches of the MEDLINE database were performed and expert opinion was sought.

RESULTS

For many patients with HCV who are treated with combination therapy, there is now a greater than 30% chance of achieving long-term normalization of transaminase levels and the loss of detectable viral load. Treatment is expensive, however, and can be difficult to tolerate. The effect of treatment on the risk of progression to liver failure and hepatocellular carcinoma is promising but has not yet been determined.

CONCLUSIONS

Primary care physicians play an important role in the diagnosis and initial workup of patients with HCV. By understanding the correct use of HCV diagnostic testing and the risks and benefits of antiviral therapy, providers will be better equipped to screen and counsel their patients infected with HCV.

Queenslanders' use of personal strategies to minimise risk of mosquito-borne disease

OBJECTIVE

To describe Queenslanders' awareness, knowledge and attitudes towards mosquito-borne diseases and their transmission, and to determine which factors influence the adoption of effective individual prevention strategies.

METHODS

In 1995-6, cross-sectional surveys of adult residents in the western suburbs of Brisbane and registered voters in Cairns were conducted. Forced entry logistic regression was used to predict use of personal protection and elimination of domestic breeding sites in the two cities.

RESULTS

Final sample sizes were 347 in Cairns and 165 in Brisbane with response rates of approximately 70%. RRVD awareness was nearly universal in both cities. A majority of residents (60% in Brisbane and 65% in Cairns) report they are careful to avoid being bitten by mosquitoes. 25% of Cairns residents and 18% of Brisbane residents report always using some method of personal protection. Cairns residents are also more likely to say that they actively prevent mosquitoes from breeding in their yards (76% in Brisbane and 87% in Cairns). Knowledge of mosquitoes and disease transmission was slightly higher in Cairns. In Brisbane, dislike of mosquitoes and being regularly bitten were significant in the multivariate model predicting personal protection, whereas concern for disease and being female were significant in Cairns. Concern about disease was a significant predictor of eliminating breeding sites in both cities.

CONCLUSIONS

Raising concern about mosquito-borne disease can increase use of personal prevention strategies. However, providing information on prevention strategies may not be effective. The most effective strategies are not practiced or seen by the public to be related to minimising risk of disease.

IMPLICATIONS

Greater emphasis in health promotion campaigns should be placed on encouraging permanent alterations to the domestic environment rather than temporary methods that are difficult to sustain and not effective against the common vectors for mosquito-borne diseases in Queensland. Educational messages should explicitly link preventive behaviours with the reduction in the likelihood of contracting a serious disease.

A modular software system for computer-aided surgery and its first application in oral implantology

Development of complex software applications in image guided therapy (IGT) is often complicated by the fact that providing basic functionality for image processing and user interaction from a graphical user interfaces (GUI) requires considerable manpower for software development. We present a programming environment that combines the high-level image processing library AVW, in-house developed patient-to-image registration procedures, and an interface to position measurement hardware. A specific application can be developed by using Tcl/Tk, a simple platform-independent scripting language, for GUI development. This environment was applied to developing VISIT, a navigation system for computer-aided implant dentistry. VISIT is presented as a result of this paper. Parts of the development environment were made accessible to the public. Future work includes the implementation of video input for connecting ultrasound or fluoroscopy units. We conclude that our approach is well suited to accelerate the development of exploratory new applications of IGT.

Evaluating trans-tethys migration: an example using acrodont lizard phylogenetics

A phylogenetic tree for acrodont lizards (Chamaeleonidae and Agamidae) is established based on 1434 bases (1041 informative) of aligned DNA positions from a 1685-1778 base pair region of the mitochondrial genome. Sequences from three protein-coding genes (ND1, ND2, and COI) are combined with sequences from eight intervening tRNA genes for samples of 70 acrodont taxa and two outgroups. Parsimony analysis of nucleotide sequences identifies eight major clades in the Acrodonta. Most agamid lizards are placed into three distinct clades. One clade is composed of all taxa occurring in Australia and New Guinea; Physignathus cocincinus from Southeast Asia is the sister taxon to the Australia-New Guinea clade. A second clade is composed of taxa occurring from Tibet and the Indian Subcontinent east through South and East Asia. A third clade is composed of taxa occurring from Africa east through Arabia and West Asia to Tibet and the Indian Subcontinent. These three clades contain all agamid lizards except Uromastyx, Leiolepis, and Hydrosaurus, which represent three additional clades of the Agamidae. The Chamaeleonidae forms another clade weakly supported as the sister taxon to the Agamidae. All eight clades of the Acrodonta contain members occurring on land masses derived from Gondwanaland. A hypothesis of agamid lizards rafting with Gondwanan plates is examined statistically. This hypothesis suggests that the African/West Asian clade is of African or Indian origin, and the South Asian clade is either of Indian or Southeast Asian origin. The shortest tree suggests a possible African origin for the former and an Indian origin for the latter, but this result is not statistically robust. The Australia-New Guinea clade rafted with the Australia-New Guinea plate and forms the sister group to a Southeast Asian taxon that occurs on plates that broke from northern Australia-New Guinea. Other acrodont taxa are inferred to be associated with the plates of Afro-Arabia and Madagascar (Chameleonidae), India (Uromastyx), or southeast Asia (Hydrosaurus and Leiolepis). Introduction of different biotic elements to Asia by way of separate Gondwanan plates may be a major theme of Asian biogeography. Three historical events may be responsible for the sharp faunal barrier between Southeast Asia and Australia-New Guinea, known as Wallace's line: (1) primary vicariance caused by plate separations; (2) secondary contact of Southeast Asian plates with Eurasia, leading to dispersal from Eurasia into Southeast Asia, and (3) dispersal of the Indian fauna (after collision of that subcontinent) to Southeast Asia. Acrodont lizards show the first and third of these biogeographic patterns and anguid lizards exhibit the second pattern. Modern faunal diversity may be influenced primarily by historical events such as tectonic collisions and land bridge connections, which are expected to promote episodic turnover of continental faunas by introducing new faunal elements into an area. Repeated tectonic collisions may be one of the most important phenomena promoting continental biodiversity. Phylogenetics is a powerful method for investigating these processes.

Evolution and phylogenetic information content of mitochondrial genomic structural features illustrated with acrodont lizards

DNA sequences from 195 squamate reptiles indicate that mitochondrial gene order is the most reliable phylogenetic character establishing monophyly of acrodont lizards and of the snake families Boidae, Colubridae, and Viperidae. Gene order shows no evidence of evolutionary parallelisms or reversals in these taxa. Derived secondary structures of mitochondrial tRNAs also prove to be useful phylogenetic characters showing no reversals. Parallelisms for secondary structures of tRNAs are restricted to deep lineages that are separated by at least 200 million years of independent evolution. Presence of a stem-and-loop structure between the genes encoding tRNA(Asn) and tRNA(Cys), where the replication origin for light-strand synthesis is typically located in vertebrate mitochondrial genomes, is found to undergo at least three and possibly as many as seven evolutionary shifts, most likely parallel losses. This character is therefore a less desirable phylogenetic marker than the other structural changes examined. Sequencing regions that contain multiple genes, including tRNA genes, may be preferable to the common practice of obtaining single-gene fragments for phylogenetic inference because it permits observation of major structural changes in the mitochondrial genome. Such characters may occasionally provide phylogenetic information on relatively short internal branches for which base substitutional changes are expected to be relatively uninformative.

Maxims or myths of beauty? A meta-analytic and theoretical review

Common maxims about beauty suggest that attractiveness is not important in life. In contrast, both fitness-related evolutionary theory and socialization theory suggest that attractiveness influences development and interaction. In 11 meta-analyses, the authors evaluate these contradictory claims, demonstrating that (a) raters agree about who is and is not attractive, both within and across cultures; (b) attractive children and adults are judged more positively than unattractive children and adults, even by those who know them; (c) attractive children and adults are treated more positively than unattractive children and adults, even by those who know them; and (d) attractive children and adults exhibit more positive behaviors and traits than unattractive children and adults. Results are used to evaluate social and fitness-related evolutionary theories and the veracity of maxims about beauty.

Roles and activities of the Commonwealth Government University Departments of Rural Health

Since 1996, University Departments of Rural Health (UDRH) have been established at Broken Hill, Mount Isa, Shepparton, Launceston, Whyalla, Alice Springs and Geraldton. Each UDRH is underpinned by Commonwealth funding for an initial period of 5 years. The role of the UDRHs is to contribute to an increase in the rural and remote health workforce through education and training programs, as well as a reduction in the health differentials between rural and urban people and between indigenous and non-indigenous peoples. A strong population health focus involving partnerships between existing health providers in a targeted region and the university sector underpins their operation. While UDRHs have been established as a means of addressing a national workforce problem, their organisational arrangements with universities and local service providers vary widely, as does the program mix of activities in education, research service development, facilitation and advocacy. This article outlines some of the activities and progress of the UDRHs to date.

Ambient pollution and heart rate variability

BACKGROUND

We investigated associations between ambient pollution levels and cardiovascular function in a repeated measures study including 163 observations on twenty-one 53- to 87-year-old active Boston residents observed up to 12 times from June to September 1997. Particles with aerodynamic diameter </=2.5 microm (PM(2.5)) were measured continuously using a tapered element oscillating microbalance.

METHODS AND RESULTS

The protocol involved 25 minutes per week of continuous Holter ECG monitoring, including 5 minutes of rest, 5 minutes of standing, 5 minutes of exercise outdoors, 5 minutes of recovery, and 20 cycles of slow breathing. Heart rate variability (HRV) was assessed through time domain variables: the standard deviation of normal RR intervals (SDNN) and the square root of the mean of the squared differences between adjacent normal RR intervals (r-MSSD). Mean 4-hour PM(2.5) levels ranged from 3 to 49 microg/m(3); 1-hour ozone levels ranged from 1 to 77 ppb. In multivariate analyses, significantly less HRV (SDNN and r-MSSD) was associated with elevated PM(2.5). During slow breathing, a reduction in r-MSSD of 6.1 ms was associated with an interquartile (14.3 microg/m(3)) increase in PM(2.5) during the hour of and the 3 hours previous to the Holter session (P=0.006). During slow breathing, a multiple pollution model was associated with a reduction in r-MSSD of 5.4 ms (P=0.02) and 5.5 ms (P=0.03) for interquartile changes in PM(2.5) and ozone, respectively, resulting in a combined effect equivalent to a 33% reduction in the mean r-MSSD.

CONCLUSIONS

Particle and ozone exposure may decrease vagal tone, resulting in reduced HRV.