940 resultados para Seasonal-changes


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This paper provides an empirical estimation of energy efficiency and other proximate factors that explain energy intensity in Australia for the period 1978-2009. The analysis is performed by decomposing the changes in energy intensity by means of energy efficiency, fuel mix and structural changes using sectoral and sub-sectoral levels of data. The results show that the driving forces behind the decrease in energy intensity in Australia are efficiency effect and sectoral composition effect, where the former is found to be more prominent than the latter. Moreover, the favourable impact of the composition effect has slowed consistently in recent years. A perfect positive association characterizes the relationship between energy intensity and carbon intensity in Australia. The decomposition results indicate that Australia needs to improve energy efficiency further to reduce energy intensity and carbon emissions. © 2012 Elsevier Ltd.

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Bats of the genus Pteropus (Pteropodidae) are recognised as the natural host of multiple emerging pathogenic viruses of animal and human health significance, including henipaviruses, lyssaviruses and ebolaviruses. Some studies have suggested that physiological and ecological factors may be associated with Hendra virus infection in flying-foxes in Australia; however, it is essential to understand the normal range and seasonal variability of physiological biomarkers before seeking physiological associations with infection status. We aimed to measure a suite of physiological biomarkers in P. alecto over time to identify any seasonal fluctuations and to examine possible associations with life-cycle and environmental stressors. We sampled 839 adult P. alecto in the Australian state of Queensland over a 12-month period. The adjusted population means of every assessed hematologic and biochemical parameter were within the reported reference range on every sampling occasion. However, within this range, we identified significant temporal variation in these parameters, in urinary parameters and body condition, which primarily reflected the normal annual life cycle. We found no evident effect of remarkable physiological demands or nutritional stress, and no indication of clinical disease driving any parameter values outside the normal species reference range. Our findings identify underlying temporal physiological changes at the population level that inform epidemiological studies and assessment of putative physiological risk factors driving Hendra virus infection in P. alecto. More broadly, the findings add to the knowledge of Pteropus populations in terms of their relative resistance and resilience to emerging infectious disease.

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This paper examines the asymmetry of changes in CO2 emissions over business cycle recessions and expansions using yearly data from 1949 and monthly data from 1973 for the United States (US). In addition, decomposition analysis is applied to investigate the relative roles of various proximate contributing factors to observed changes in total and per capita CO2 emissions and emissions intensity, over business cycle phases. The results suggest, inter alia, that aggregate emissions and emissions intensity reduce much faster in contractions than they increase in expansions. In addition, unlike the three previous expansions, in the most recent post-GFC US expansion, emissions per capita have continued to decline, and at a rate very similar to the rate of reduction in preceding contractions. This suggests the real possibility that the most recent contraction may have had an ongoing impact on the path of per capita emissions well beyond the immediate impact experienced during the contraction itself.

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While much has been written about the relationship between personal epistemologies and learning-teaching approaches, outcomes, and intentions, little has focused specifically on these relationships in the context of teacher education. This chapter addresses changes in preservice teachers’ personal epistemologies by overviewing this emerging body of research and arguing for a new approach to conceptualizing and supporting changes in personal epistemologies based on reflexivity. The overview includes definitions of key concepts and research traditions that have been used since the 1970s and a discussion of the emerging role of epistemic justification as a key mechanism of change in the process of belief development.

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PURPOSE To examine longitudinal changes in choroidal thickness and axial length in a population of children with a range of refractive errors. METHODS One hundred and one children (41 myopes and 60 nonmyopes) aged 10 to 15 years participated in this prospective, observational longitudinal study. For each child, 6-month measures of choroidal thickness (using enhanced depth imaging optical coherence tomography) and axial ocular biometry were collected four times over an 18-month period. Linear mixed-models were used to examine the longitudinal changes in choroidal thickness and the relationship between changes in choroidal thickness and axial eye growth over the study period. RESULTS A significant group mean increase in subfoveal choroidal thickness was observed over 18 months (mean increase 13 6 22 lm, P < 0.001). Myopic children exhibited significantly thinner choroids compared with nonmyopic children (P < 0.001), although there was no significant time by refractive group interaction (P ¼ 0.46), indicating similar changes in choroidal thickness over time in myopes and nonmyopes. However, a significant association between the change in choroidal thickness and the change in axial length over time was found (P < 0.001, β = −0.14). Children showing faster axial eye growth exhibited significantly less choroidal thickening over time compared with children showing slower axial eye growth. CONCLUSIONS A significant increase in choroidal thickness occurs over an 18-month period in normal 10- to 15-year-old children. Children undergoing faster axial eye growth exhibited less thickening and, in some cases, a thinning of the choroid. These findings support a potential role for the choroid in the mechanisms regulating eye growth in childhood.

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• Evidence from cross-sectional studies1,2 suggests that choroidal thickness (ChT) varies with age and refractive error in childhood. However, to date there have been no longitudinal studies examining changes in pediatric ChT. • In this prospective study, the longitudinal changes in ChT and its relationship with eye growth were examined in a population of normal children with a range of refractive errors.

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High Intensity Exercise (HIE) stimulates greater physiological remodeling when compared to workload matched low-moderate intensity exercise. This study utilized an untargeted metabolomics approach to examine the metabolic perturbations that occur following two workload matched supramaximal low volume HIE trials. In a randomized order, 7 untrained males completed two exercise protocols separated by one week; 1) HIE150%: 30 x 20s cycling at 150% VO2peak, 40s passive rest; 2) HIE300%: 30 x 10s cycling at 300% VO2peak, 50 s passive rest. Total exercise duration was 30 minutes for both trials. Blood samples were taken at rest, during and immediately following exercise and at 60 minutes post exercise. Gas chromatography-mass spectrometry (GC-MS) analysis of plasma identified 43 known metabolites of which 3 demonstrated significant fold changes (HIE300% compared to the HIE150% value) during exercise, 14 post exercise and 23 at the end of the recovery period. Significant changes in plasma metabolites relating to lipid metabolism [fatty acids: dodecanoate (p=0.042), hexadecanoate (p=0.001), octadecanoate (p=0.001)], total cholesterol (p=0.001), and glycolysis [lactate (p=0.018)] were observed following exercise and during the recovery period. The HIE300% protocol elicited greater metabolic changes relating to lipid metabolism and glycolysis when compared to HIE150% protocol. These changes were more pronounced throughout the recovery period rather than during the exercise bout itself. Data from the current study demonstrate the use of metabolomics to monitor intensity-dependent changes in multiple metabolic pathways following exercise. The small sample size indicates a need for further studies in a larger sample cohort to validate these findings.

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In the 21st century, human-induced global climate change has been highlighted as one of the most serious threats to ecosystems worldwide. According to global climate scenarios, the mean temperature in Finland is expected to increase by 1.8 4.0°C by the end of the century. The regional and seasonal change in temperature has predicted to be spatially and temporally asymmetric, where the High-Arctic and Antarctic areas and winter and spring seasons have been projected to face the highest temperature increase. To understand how species respond to the ongoing climate change, we need to study how climate affects species in different phases of their life cycle. The impact of climate on breeding and migration of eight large-sized bird species was studied in this thesis, taking food availability into account. The findings show that climatic variables have considerable impact on the life-history traits of large-sized birds in northern Europe. The magnitude of climatic effects on migration and breeding was comparable with that of food supply, conventionally regarded as the main factor affecting these life-history traits. Based on the results of this thesis and the current climate scenarios, the following not mutually exclusive responses are possible in the near future. Firstly, asymmetric climate change may result in a mistiming of breeding because mild winters and early spring may lead to earlier breeding, whereas offspring are hatching into colder conditions which elevate mortality. Secondly, climate induced responses can differ between species with different breeding tactics (income vs. capital breeding), so that especially capital breeders can gain advantage on global warming as they can sustain higher energy resources. Thirdly, increasing precipitation has the potential to reduce the breeding success of many species by exposing nestlings to more severe post-hatching conditions and hampering the hunting conditions of parents. Fourthly, decreasing ice cover and earlier ice-break in the Baltic Sea will allow earlier spring migration in waterfowl. In eiders, this can potentially lead to more productive breeding. Fifthly, warming temperatures can favour parents preparing for breeding and increase nestling survival. Lastly, the climate-induced phenological changes in life history events will likely continue. Furthermore, interactions between climate and food resources can be complex and interact with each other. Eiders provide an illustrative example of this complexity, being caught in the crossfire between more benign ice conditions and lower salinity negatively affecting their prime food resource. The general conclusion is that climate is controlling not only the phenology of the species but also their reproductive output, thus affecting the entire population dynamics.

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The doctoral thesis defined connections between circadian rhythm disruptions and health problems. Sleep debt, jet-lag, shift work, as well as transitions into and out of the daylight saving time may lead to circadian rhythm disruptions. Disturbed circadian rhythm causes sleep deprivation and decrease of mood and these effects may lead to higher accident rates and trigger mental illnesses. Circadian clock genes are involved in the regulation of the cell cycle and metabolism and thus unstable circadian rhythmicity may also lead to cancer development. In publications I-III it was explored how transitions into and out of the daylight saving time impact the sleep efficiency and the rest-activity cycles of healthy individuals. Also it was explored whether the effect of transition is different in fall as compared to spring, and whether there are subgroup specific differences in the adjustment to transitions into and out of daylight saving time. The healthy participants of studies I-III used actigraphs before and after the transitions and filled in the morningness-eveningness and seasonal pattern assessment questionnaires. In publication IV the incidence of hospital-treated accidents and manic episodes was explored two weeks before and two weeks after the transitions into and out of the daylight saving time in years 1987-2003. In publication V the relationship between circadian rhythm disruption and the prevalence of Non-Hodgkin lymphoma was studied. The study V consisted of all working aged Finns who participated in the national population census in 1970. For our study, all the cancers diagnosed during the years 1971-1995 were extracted from the Finnish Cancer Register and linked with the 1970 census files. In studies I-III it was noticed that transitions into and out of the daylight saving time disturbs the sleep-wake cycle and the sleep efficiency of the healthy participants. We also noticed that short sleepers were more sensitive than long sleepers for sudden changes in the circadian rhythm. Our results also indicated that adaptation to changes in the circadian rhythm is potentially sex, age and chronotype-specific. In study IV no significant increase in the occurrence of hospital treated accidents or manic episodes was noticed. However, interesting observations about the seasonal fluctuation of the occurrence rates of accidents and manic episodes were made. Study V revealed that there might be close relationship between circadian rhythm disruption and cancer. The prevalence of Non-Hodgkin lymphoma was the highest among night workers. The five publications included in this thesis together point out that disturbed circadian rhythms may have adverse effect on health. Disturbed circadian rhythms decrease the quality of sleep and weaken the sleep-wake cycle. A continuous circadian rhythm disruption may also predispose individuals to cancer development. Since circadian rhythm disruptions are common in modern society they might have a remarkable impact on the public health. Thus it is important to continue circadian rhythm research so that better prevention and treatment methods can be developed. Keywords: Circadian rhythm, daylight saving time, manic episodes, accidents, Non-Hodgkin lymphoma 11

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In northern latitudes, temperature is the key factor driving the temporal scales of biological activity, namely the length of the growing season and the seasonal efficiency of photosynthesis. The formation of atmospheric concentrations of biogenic volatile organic compounds (BVOCs) are linked to the intensity of biological activity. However, interdisciplinary knowledge of the role of temperature in the biological processes related to the annual cycle and photosynthesis and atmospheric chemistry is not fully understood. The aim of this study was to improve understanding of the role of temperature in these three interlinked areas: 1) onset of growing season, 2) photosynthetic efficiency and 3) BVOC air concentrations in a boreal forest. The results present a cross-section of the role of temperature on different spatial (southern northern boreal), structural (tree forest stand - forest) and temporal (day-season- year) scales. The fundamental status of the Thermal Time model in predicting the onset of spring recovery was confirmed. However, it was recommended that sequential models would be more appropriate tools when the onset of the growing season is estimated under a warmer climate. A similar type of relationship between photosynthetic efficiency and temperature history was found in both southern and northern boreal forest stands. This result draws attention to the critical question of the seasonal efficiency of coniferous species to emit organic compounds under a warmer climate. New knowledge about the temperature dependence of the concentrations of biogenic volatile organic compounds in a boreal forest stand was obtained. The seasonal progress and the inter-correlation of BVOC concentrations in ambient air indicated a link to biological activity. Temperature was found to be the main driving factor for the concentrations. However, in addition to temperature, other factors may play a significant role here, especially when the peak concentrations are studied. There is strong evidence that the spring recovery and phenological events of many plant species have already advanced in Europe. This study does not fully support this observation. In a boreal forest, changes in the annual cycle, especially the temperature requirement in winter, would have an impact on the atmospheric BVOC composition. According to this study, more joint phenological and BVOC field observations and laboratory experiments are still needed to improve these scenarios.

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Staphylococcus aureus is one of the most important bacteria that cause disease in humans, and methicillin-resistant S. aureus (MRSA) has become the most commonly identified antibiotic-resistant pathogen in many parts of the world. MRSA rates have been stable for many years in the Nordic countries and the Netherlands with a low MRSA prevalence in Europe, but in the recent decades, MRSA rates have increased in those low-prevalence countries as well. MRSA has been established as a major hospital pathogen, but has also been found increasingly in long-term facilities (LTF) and in communities of persons with no connections to the health-care setting. In Finland, the annual number of MRSA isolates reported to the National Infectious Disease Register (NIDR) has constantly increased, especially outside the Helsinki metropolitan area. Molecular typing has revealed numerous outbreak strains of MRSA, some of which have previously been associated with community acquisition. In this work, data on MRSA cases notified to the NIDR and on MRSA strain types identified with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and staphylococcal cassette chromosome mec (SCCmec) typing at the National Reference Laboratory (NRL) in Finland from 1997 to 2004 were analyzed. An increasing trend in MRSA incidence in Finland from 1997 to 2004 was shown. In addition, non-multi-drug resistant (NMDR) MRSA isolates, especially those resistant only to methicillin/oxacillin, showed an emerging trend. The predominant MRSA strains changed over time and place, but two internationally spread epidemic strains of MRSA, FIN-16 and FIN-21, were related to the increase detected most recently. Those strains were also one cause of the strikingly increasing invasive MRSA findings. The rise of MRSA strains with SCCmec types IV or V, possible community-acquired MRSA was also detected. With questionnaires, the diagnostic methods used for MRSA identification in Finnish microbiology laboratories and the number of MRSA screening specimens studied were reviewed. Surveys, which focused on the MRSA situation in long-term facilities in 2001 and on the background information of MRSA-positive persons in 2001-2003, were also carried out. The rates of MRSA and screening practices varied widely across geographic regions. Part of the NMDR MRSA strains could remain undetected in some laboratories because of insufficient diagnostic techniques used. The increasing proportion of elderly population carrying MRSA suggests that MRSA is an emerging problem in Finnish long-term facilities. Among the patients, 50% of the specimens were taken on a clinical basis, 43% on a screening basis after exposure to MRSA, 3% on a screening basis because of hospital contact abroad, and 4% for other reasons. In response to an outbreak of MRSA possessing a new genotype that occurred in a health care ward and in an associated nursing home of a small municipality in Northern Finland in autumn 2003, a point-prevalence survey was performed six months later. In the same study, the molecular epidemiology of MRSA and methicillin-sensitive S. aureus (MSSA) strains were also assessed, the results to the national strain collection compared, and the difficulties of MRSA screening with low-level oxacillin-resistant isolates encountered. The original MRSA outbreak in LTF, which consisted of isolates possessing a nationally new PFGE profile (FIN-22) and internationally rare MLST type (ST-27), was confined. Another previously unrecognized MRSA strain was found with additional screening, possibly indicating that current routine MRSA screening methods may be insufficiently sensitive for strains possessing low-level oxacillin resistance. Most of the MSSA strains found were genotypically related to the epidemic MRSA strains, but only a few of them had received the SCCmec element, and all those strains possessed the new SCCmec type V. In the second largest nursing home in Finland, the colonization of S. aureus and MRSA, and the role of screening sites along with broth enrichment culture on the sensitivity to detect S. aureus were studied. Combining the use of enrichment broth and perineal swabbing, in addition to nostrils and skin lesions swabbing, may be an alternative for throat swabs in the nursing home setting, especially when residents are uncooperative. Finally, in order to evaluate adequate phenotypic and genotypic methods needed for reliable laboratory diagnostics of MRSA, oxacillin disk diffusion and MIC tests to the cefoxitin disk diffusion method at both +35°C and +30°C, both with or without an addition of sodium chloride (NaCl) to the Müller Hinton test medium, and in-house PCR to two commercial molecular methods (the GenoType® MRSA test and the EVIGENETM MRSA Detection test) with different bacterial species in addition to S. aureus were compared. The cefoxitin disk diffusion method was superior to that of oxacillin disk diffusion and to the MIC tests in predicting mecA-mediated resistance in S. aureus when incubating at +35°C with or without the addition of NaCl to the test medium. Both the Geno Type® MRSA and EVIGENETM MRSA Detection tests are usable, accurate, cost-effective, and sufficiently fast methods for rapid MRSA confirmation from a pure culture.

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Long-term monitoring data collected from wild smolts of Atlantic salmon (Salmo salar) in the Simojoki river, northern Finland, were used in studying the relationships between the smolt size and age, smolt and postsmolt migration, environmental conditions and postsmolt survival. The onset of the smolt run was significantly dependent on the rising water temperature and decreasing discharge of the river in the spring. The mean length of smolts migrating early in the season was commonly higher and the mean age always older than among smolts migrating later. Many of the smolts migrating early in the season and almost all smolts migrating later had started their new growth in spring in the river before their sea entry. Among postsmolts, the time required for emigration from the estuary was dependent on the sea surface temperature (SST) off the river, being significantly shorter in years with warm than cold sea temperatures. After leaving the estuary, the postsmolts migrated southwards along the eastern coast of the northern Gulf of Bothnia, the geographical distribution of the tag recoveries coinciding with the warm thermal zone in spring in the coastal area. After arriving in the southern Gulf of Bothnia in late summer the postsmolts mostly migrated near the western coast, reaching the Baltic Main Basin in late autumn. Until the early 1990s there was only a weak positive association between smolt length and postsmolt survival. However, following a subsequent decrease in the mean smolt size, a significant positive dependence was observed between smolt size and the reported recapture rate of tagged salmon. The differences in recapture rates between smolts tagged during the first and second half of the annual migration season were insignificant, indicating that the seasonal variation in smolt size and age seem to be too small to affect survival. Among the climatic factors examined, the summer SST in the Gulf of Bothnia was most clearly related to the survival of the wild postsmolts. Postsmolt survival appeared to be highest in years when the SST in June in the Bothnian Bay varied between 9 and 12 ºC. In addition, the survival of wild postsmolts showed a significant positive dependence on the SST in July in the Bothnian Sea, but not on the abundance of the prey fish (0+ herring, Clupea harengus and sprat, Sprattus sprattus) in the Bothnian Sea and in the Baltic Main Basin. The results suggest, that if the incidence of extreme weather conditions were to increase due to climatic changes, it would probably reduce the postsmolt survival of wild salmon populations. For improving the performance of hatchery-reared smolts, it could be useful to examine opportunities to produce smolts that are in their smolt traits and abilities more similar to the wild smolts described in this thesis.

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On 22 October 2012, the Australian Federal Government announced the removal of the $1,000 in-house fringe benefits concession when used as part of a salary packaging arrangement. At the time of the announcement, the Federal Government predicted that the removal of the concession would contribute additional tax revenue of $445 million over the following four years as well as an increase of GST payments to the States and Territories. However, anecdotal evidence at the same time indicated that the Australian employer response was to immediately stop providing employees with such in-house fringe benefits via salary sacrificing arrangements. Data presented in this article, collected from a combination of interviews with tax managers of four Australian entities as well as a review of the published archival data, confirms that the abolition of the $1,000 in-house fringe benefits concession was perceived as a negative change, whereby employees were considered the ‘big losers’ despite assertions by the Federal Government to the contrary. Using a conceptual map of tax rule change developed by Oats and Sadler, this article seeks to understand the reasons for this fringe benefits tax change and taxpayer response. In particular, the economic and political factors, and the responses of the relevant taxpayers (employers) are explored. Drawing on behavioural economic concepts, the actions, attitudes and response of employers to the rule change are also examined. The research findings suggest that the decision by Australian employers to cease providing the in-house fringe benefits as part of a salary-packaging arrangement after the legislative amendment was impacted by more than simple rational behaviour.