113 research outputs found

    Third eye

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    40 p. : ill. ; 24 cm.Includes bibliographical references (p. 36-40)."The function of the parietal eye in four species of western North American lizards was investigated by surgical removal of the 'eye' (parietalectomy) and by covering the 'eye' with aluminum foil. The species studied were Sceloporus occidentalis, S. undulatus, Uta stansburiana, and Uma inornata; the first two species were investigated most intensively. A population of Sceloporus occidentalis in Berkeley Hills, California, was studied from September, 1955, to June, 1957. Marked parietalectomized and sham-operated individuals were returned to the field to original points of capture, and their subsequent behavior was observed. The two surgical types were always introduced in equal numbers. Other lizards were studied in photothermal gradients in the laboratory. The following results were obtained: 1. Individuals of all four species increased their exposure to sunlight (or artificial light in the laboratory) following removal of the parietal eye. There was prolongation of the time spent exposed on the surface of the ground and greater use of high-intensity illumination. 2. Although these lizards are heliotherms, depending directly on the sun for elevation of their body temperature to desired levels, no differences were found between the parietalectomized and control lizards in body temperatures recorded during the period of surface activity. Both in the field and laboratory, however, the parietalectomized lizards extended the length of time spent at the thermal levels of 'normal activity.' 3. The increased exposure to sunlight following parietalectomy is accompanied by increased locomotory activity, as judged by the restive behavior of captives and the shifts in position of surgically treated lizards released in the field. The parietalectomized animals average three times greater displacement from previously determined home ranges than the sham-operated animals. 4. The parietalectomized lizards were less inclined to retreat upon the approach of the observer than were the sham-operated ones. The pronounced heliothermism perhaps works antagonistically to the normal retreat reaction. 5. The thyroid gland of parietalectomized lizards tended to show hypertrophy and loss of colloid, which suggests that there is a relationship between thyroid and the behavioral changes observed. 6. That sunlight is the stimulus to the parietal eye seems indicated by the increased heliothermism that occurred following the use of aluminum foil shields over the 'eye.' In experiments with foil, the parietal eye was left intact. 7. Parietalectomized lizards deprived of food appeared to be less viable than sham-operated lizards. Increased metabolism probably resulted in more rapid exhaustion of their energy reserves. Additional work is, however, required before this point can be fully documented. 8. Microsections of the parietal eye of Sceloporus failed to reveal any nerve connection between the 'eye' and the brain. The retina of the 'eye' appears to be secretory, and its activity probably fluctuates with the intensity of solar radiation to which the eye is exposed. It may be concluded that the parietal eye in the diurnal lizards studied functions in helping to regulate the amount of exposure to sunlight. After a period of exposure, the length of time probably varying with changes in the duration and intensity of sunlight and the physiological condition of the animal, inhibition to activity begins. Because exposure to sunlight is required to maintain normal activity levels, parietal-eye inhibition may function to prevent metabolic excesses and to insure the maintenance of energy reserves. The 'eye' thus may influence the intensity and perhaps also the duration of the life of the animal"--P. 35-36

    Impacts of climate change on World Heritage coral reefs: a first global scientific assessment

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    Since 1972, the UNESCO World Heritage Convention has united the world around a shared responsibility to protect natural and cultural places of Outstanding Universal Value (OUV). The World Heritage List includes 29 natural, marine properties that contain coral reef systems. Stretching around the planet, these globally significant reefs include icons such as the Phoenix Islands Protected Area (Kiribati), the Great Barrier Reef (Australia), Papahānaumokuākea (USA), Belize Barrier Reef Reserve System (Belize) and Tubbataha Reefs Natural Park (Philippines). They are recognized for their unique and global importance and for being part of the common heritage of humanity. Coral reefs are ecologically and economically important ecosystems found across the world’s tropical and sub-tropical oceans. Despite covering less than 0.1% of the ocean floor, reefs host more than one quarter of all marine fish species (in addition to many other marine animals). They are the most inherently biodiverse ecosystems in the ocean – comparable to rainforests on land. These ‘Rainforests of the Sea’ provide social, economic and cultural services with an estimated value of over USD $1 Trillion globally. For example, the complex three-dimensional structure of reefs not only provides habitat but also dissipates wave energy to protect coastlines from erosion and damage. Coastal protection and human use (including tourism, recreation and fishing) supply the greatest economic benefits from coral reefs to over half a billion people around the world. Despite their importance and value, most coral reefs are under enormous pressure from a range of different human activities globally including agricultural run-off, urban development, and over-fishing. Superimposed on these local threats, increased ocean temperature has caused the death of corals around the world in recent years. At this point, rising atmospheric carbon dioxide caused by human activity is the greatest threat to coral reefs globally, primarily due to ocean warming but also due to ocean acidification that ensues

    Cost-Effectiveness of a Telephone-Delivered Intervention for Physical Activity and Diet

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    Background: Given escalating rates of chronic disease, broad-reach and cost-effective interventions to increase physical activity and improve dietary intake are needed. The cost-effectiveness of a Telephone Counselling intervention to improve physical activity and diet, targeting adults with established chronic diseases in a low socio-economic area of a major Australian city was examined. Methodology/Principal Findings: A cost-effectiveness modelling study using data collected between February 2005 and November 2007 from a cluster-randomised trial that compared Telephone Counselling with a “Usual Care” (brief intervention) alternative. Economic outcomes were assessed using a state-transition Markov model, which predicted the progress of participants through five health states relating to physical activity and dietary improvement, for ten years after recruitment. The costs and health benefits of Telephone Counselling, Usual Care and an existing practice (Real Control) group were compared. Telephone Counselling compared to Usual Care was not cost-effective (78,489perqualityadjustedlifeyeargained).However,theUsualCaregroupdidnotrepresentexistingpracticeandisnotausefulcomparatorfordecisionmaking.ComparingTelephoneCounsellingoutcomestoexistingpractice(RealControl),theinterventionwasfoundtobecosteffective(78,489 per quality adjusted life year gained). However, the Usual Care group did not represent existing practice and is not a useful comparator for decision making. Comparing Telephone Counselling outcomes to existing practice (Real Control), the intervention was found to be cost-effective (29,375 per quality adjusted life year gained). Usual Care (brief intervention) compared to existing practice (Real Control) was also cost-effective ($12,153 per quality adjusted life year gained). Conclusions/Significance: This modelling study shows that a decision to adopt a Telephone Counselling program over existing practice (Real Control) is likely to be cost-effective. Choosing the ‘Usual Care’ brief intervention over existing practice (Real Control) shows a lower cost per quality adjusted life year, but the lack of supporting evidence for efficacy or sustainability is an important consideration for decision makers. The economics of behavioural approaches to improving health must be made explicit if decision makers are to be convinced that allocating resources toward such programs is worthwhile

    Results from the dissemination of an evidence-based telephone-delivered intervention for healthy lifestyle and weight loss: the Optimal Health Program

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    Despite proven efficacy, there are few published evaluations of telephone-delivered interventions targeting physical activity, healthy eating, and weight loss in community dissemination contexts. This study aims to evaluate participant and program outcomes from the Optimal Health Program, a telephone-delivered healthy lifestyle and weight loss program provided by a primary health care organization. Dissemination study used a single-group, repeated measures design; outcomes were assessed at 6-month (mid-program; n = 166) and 12-month (end of program; n = 88) using paired analyses. The program reached a representative sample of at-risk, primary care patients, with 56 % withdrawing before program completion. Among completers, a statistically significant improvement between baseline and end of program was observed for weight [mean change (SE) −5.4 (7.0) kg] and waist circumference [−4.8 (9.7) cm], underpinned by significant physical activity and dietary change. Findings suggest that telephone-delivered weight loss and healthy lifestyle programs can provide an effective model for use in primary care settings, but participant retention remains a challenge

    Characteristics of control group participants who increased their physical activity in a cluster-randomized lifestyle intervention trial

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    <p>Abstract</p> <p>Background</p> <p>Meaningful improvement in physical activity among control group participants in lifestyle intervention trials is not an uncommon finding, and may be partly explained by participant characteristics. This study investigated which baseline demographic, health and behavioural characteristics were predictive of successful improvement in physical activity in usual care group participants recruited into a telephone-delivered physical activity and diet intervention trial, and descriptively compared these characteristics with those that were predictive of improvement among intervention group participants.</p> <p>Methods</p> <p>Data come from the Logan Healthy Living Program, a primary care-based, cluster-randomized controlled trial of a physical activity and diet intervention. Multivariable logistic regression models examined variables predictive of an improvement of at least 60 minutes per week of moderate-to-vigorous intensity physical activity among usual care (n = 166) and intervention group (n = 175) participants.</p> <p>Results</p> <p>Baseline variables predictive of a meaningful change in physical activity were different for the usual care and intervention groups. Being retired and completing secondary school (but no further education) were predictive of physical activity improvement for usual care group participants, whereas only baseline level of physical activity was predictive of improvement for intervention group participants. Higher body mass index and being unmarried may also be predictors of physical activity improvement for usual care participants.</p> <p>Conclusion</p> <p>This is the first study to examine differences in predictors of physical activity improvement between intervention group and control group participants enrolled in a physical activity intervention trial. While further empirical research is necessary to confirm findings, results suggest that participants with certain socio-demographic characteristics may respond favourably to minimal intensity interventions akin to the treatment delivered to participants in a usual care group. In future physical activity intervention trials, it may be possible to screen participants for baseline characteristics in order to target minimal-intensity interventions to those most likely to benefit. (Australian Clinical Trials Registry, <url>http://www.anzctr.org.au/default.aspx</url>, ACTRN012607000195459)</p

    Living Well with Diabetes: a randomized controlled trial of a telephone-delivered intervention for maintenance of weight loss, physical activity and glycaemic control in adults with type 2 diabetes

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    Background By 2025, it is estimated that approximately 1.8 million Australian adults (approximately 8.4% of the adult population) will have diabetes, with the majority having type 2 diabetes. Weight management via improved physical activity and diet is the cornerstone of type 2 diabetes management. However, the majority of weight loss trials in diabetes have evaluated short-term, intensive clinic-based interventions that, while producing short-term outcomes, have failed to address issues of maintenance and broad population reach. Telephone-delivered interventions have the potential to address these gaps. Methods/Design Using a two-arm randomised controlled design, this study will evaluate an 18-month, telephone-delivered, behavioural weight loss intervention focussing on physical activity, diet and behavioural therapy, versus usual care, with follow-up at 24 months. Three-hundred adult participants, aged 20-75 years, with type 2 diabetes, will be recruited from 10 general practices via electronic medical records search. The Social-Cognitive Theory driven intervention involves a six-month intensive phase (4 weekly calls and 11 fortnightly calls) and a 12-month maintenance phase (one call per month). Primary outcomes, assessed at 6, 18 and 24 months, are: weight loss, physical activity, and glycaemic control (HbA1c), with weight loss and physical activity also measured at 12 months. Incremental cost-effectiveness will also be examined. Study recruitment began in February 2009, with final data collection expected by February 2013. Discussion This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes. The evaluation of maintenance outcomes (6 months following the end of intervention), the use of accelerometers to objectively measure physical activity, and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change, and will build the evidence base needed to advocate for the translation of this work into population health practice

    Global warming and recurrent mass bleaching of corals

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    During 2015–2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs

    Historical Temperature Variability Affects Coral Response to Heat Stress

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    Coral bleaching is the breakdown of symbiosis between coral animal hosts and their dinoflagellate algae symbionts in response to environmental stress. On large spatial scales, heat stress is the most common factor causing bleaching, which is predicted to increase in frequency and severity as the climate warms. There is evidence that the temperature threshold at which bleaching occurs varies with local environmental conditions and background climate conditions. We investigated the influence of past temperature variability on coral susceptibility to bleaching, using the natural gradient in peak temperature variability in the Gilbert Islands, Republic of Kiribati. The spatial pattern in skeletal growth rates and partial mortality scars found in massive Porites sp. across the central and northern islands suggests that corals subject to larger year-to-year fluctuations in maximum ocean temperature were more resistant to a 2004 warm-water event. In addition, a subsequent 2009 warm event had a disproportionately larger impact on those corals from the island with lower historical heat stress, as indicated by lower concentrations of triacylglycerol, a lipid utilized for energy, as well as thinner tissue in those corals. This study indicates that coral reefs in locations with more frequent warm events may be more resilient to future warming, and protection measures may be more effective in these regions

    Contrasting Patterns of Coral Bleaching Susceptibility in 2010 Suggest an Adaptive Response to Thermal Stress

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    Background: \ud Coral bleaching events vary in severity, however, to date, the hierarchy of susceptibility to bleaching among coral taxa has been consistent over a broad geographic range and among bleaching episodes. Here we examine the extent of spatial and temporal variation in thermal tolerance among scleractinian coral taxa and between locations during the 2010 thermally induced, large-scale bleaching event in South East Asia.\ud \ud Methodology/Principal Findings: \ud Surveys to estimate the bleaching and mortality indices of coral genera were carried out at three locations with contrasting thermal and bleaching histories. Despite the magnitude of thermal stress being similar among locations in 2010, there was a remarkable contrast in the patterns of bleaching susceptibility. Comparisons of bleaching susceptibility within coral taxa and among locations revealed no significant differences between locations with similar thermal histories, but significant differences between locations with contrasting thermal histories (Friedman = 34.97; p,0.001). Bleaching was much less severe at locations that bleached during 1998, that had greater historical temperature variability and lower rates of warming. Remarkably, Acropora and Pocillopora, taxa that are typically highly susceptible, although among the most susceptible in Pulau Weh (Sumatra, Indonesia) where respectively, 94% and 87% of colonies died, were among the least susceptible in Singapore, where only 5% and 12% of colonies died.\ud \ud Conclusions/Significance: \ud The pattern of susceptibility among coral genera documented here is unprecedented. A parsimonious explanation for these results is that coral populations that bleached during the last major warming event in 1998 have adapted and/or acclimatised to thermal stress. These data also lend support to the hypothesis that corals in regions subject to more variable temperature regimes are more resistant to thermal stress than those in less variable environments

    The impact of physical activity on fatigue and quality of life in lung cancer patients: a randomised controlled trial protocol

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    Background: People with lung cancer have substantial symptom burden and more unmet needs than the general cancer population. Physical activity (PA) has been shown to positively influence quality of life (QOL), fatigue and daily functioning in the curative treatment of people with breast and colorectal cancers and lung diseases, as well as in palliative settings. A randomised controlled trial (RCT) is needed to determine if lung cancer patients benefit from structured PA intervention. The Physical Activity in Lung Cancer (PAL) trial is designed to evaluate the impact of a 2-month PA intervention on fatigue and QOL in patients with non-resectable lung cancer. Biological mechanisms will also be studied.Methods/design: A multi-centre RCT with patients randomised to usual care or a 2-month PA programme, involving supervised PA sessions including a behavioural change component and home-based PA. QOL questionnaires, disease and functional status and body composition will be assessed at baseline, 2, 4 and 6 months follow-up. The primary endpoint is comparative levels of fatigue between the 2 arms. Secondary endpoints include: QOL, functional abilities and physical function. Exploratory endpoints include: anxiety, depression, distress, dyspnoea, PA behaviour, fitness, hospitalisations, survival, cytokines and insulin-like growth factor levels.Discussion: This study will provide high-level evidence of the effect of PA programmes on cancer-related fatigue and QOL in patients with advanced lung cancer. If positive, the study has the potential to change care for people with cancer using a simple, inexpensive intervention to improve their QOL and help them maintain independent function for as long as possible.Trial registration: Australian New Zealand Clinical Trials Registry No. ACTRN12609000971235. © 2012 Dhillon et al.; licensee BioMed Central Ltd
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