863 resultados para Short-term Exercise


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This study compared the effects of a low-frequency electrical stimulation (LFES; Veinoplus® Sport, Ad Rem Technology, Paris, France), a low-frequency electrical stimulation combined with a cooling vest (LFESCR) and an active recovery combined with a cooling vest (ACTCR) as recovery strategies on performance (racing time and pacing strategies), physiologic and perceptual responses between two sprint kayak simulated races, in a hot environment (∼32 wet-bulb-globe temperature). Eight elite male kayakers performed two successive 1000-m kayak time trials (TT1 and TT2), separated by a short-term recovery period, including a 30-min of the respective recovery intervention protocol, in a randomized crossover design. Racing time, power output, and stroke rate were recorded for each time trial. Blood lactate concentration, pH, core, skin and body temperatures were measured before and after both TT1 and TT2 and at mid- and post-recovery intervention. Perceptual ratings of thermal sensation were also collected. LFESCR was associated with a very likely effect in performance restoration compared with ACTCR (99/0/1%) and LFES conditions (98/0/2%). LFESCR induced a significant decrease in body temperature and thermal sensation at post-recovery intervention, which is not observed in ACTCR condition. In conclusion, the combination of LFES and wearing a cooling vest (LFESCR) improves performance restoration between two 1000-m kayak time trials achieved by elite athletes, in the heat.

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Previous short-term studies predict that the use of fire to manage lantana (Lantana camara) may promote its abundance. We tested this prediction by examining long-term recruitment patterns of lantana in a dry eucalypt forest in Australia from 1959 to 2007 in three fire frequency treatments: repeated annual burning, repeated triennial burning and long unburnt. The dataset was divided into two periods (1959–1972, 1974–2007) due to logging that occurred at the study site between 1972 and 1974 and the establishment of the triennial burn treatment in 1973. Our results showed that repeated burning decreased lantana regeneration under an annual burn regime in the pre- and post-logging periods and maintained low levels of regeneration in the triennial burn compartment during the post-logging period. In the absence of fire, lantana recruitment exhibited a dome-shaped response over time, with the total population peaking in 1982 before declining to 2007. In addition to fire regime, soil pH and carbon to nitrogen ratio, the density of taller conspecifics and the interaction between rainfall and fire regime were found to influence lantana regeneration change over time. The results suggest that the reported positive association between fire disturbance and abundance of lantana does not hold for all forest types and that fire should be considered as part of an integrated weed management strategy for lantana in more fire-tolerant ecosystems.

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This study investigated long-term use of custom-made orthopedic shoes (OS) at 1.5 years follow-up. In addition, the association between short-term outcomes and long-term use was studied. Patients from a previously published study who did use their first-ever pair of OS 3 months after delivery received another questionnaire after 1.5 years. Patients with different pathologies were included in the study (n = 269, response = 86%). Mean age was 63 ± 14 years, and 38% were male. After 1.5 years, 87% of the patients still used their OS (78% frequently [4-7 days/week] and 90% occasionally [1-3 days/week]) and 13% of the patients had ceased using their OS. Patients who were using their OS frequently after 1.5 years had significantly higher scores for 8 of 10 short-term usability outcomes (p-values ranged from <0.001 to 0.046). The largest differences between users and nonusers were found for scores on the short-term outcomes of OS fit and communication with the medical specialist and shoe technician (effect size range = 0.16 to 0.46). We conclude that patients with worse short-term usability outcomes for their OS are more likely to use their OS only occasionally or not at all at long-term follow-up.

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Background Australia has one of the highest rates of antibiotic use amongst OECD countries. Data from the Australian primary healthcare sector suggests unnecessary antibiotics were prescribed for self-resolving conditions. We need to better understand what drives general practitioners (GPs) to prescribe antibiotics, consumers to seek antibiotics, and pharmacists to fill repeat antibiotic prescriptions. It is also not clear how these individuals trade-off between the possible benefits that antibiotics may provide in the immediate/short term, against the longer term societal risk of antimicrobial resistance. This project investigates what factors drive decisions to use antibiotics for GPs, pharmacists and consumers, and how these individuals discount the future. Methods Factors will be gleaned from published literature and from semi-structured interviews, to inform the development of Discrete Choice Experiments (DCEs). Three DCEs will be constructed – one for each group of interest – to allow investigation of which factors are more important in influencing (a) GPs to prescribe antibiotics, (b) consumers to seek antibiotics, and (c) pharmacists to fill legally valid but old or repeat prescriptions of antibiotics. Regression analysis will be conducted to understand the relative importance of these factors. A Time Trade Off exercise will be developed to investigate how these individuals discount the future. Results Findings from the DCEs will provide an insight into which factors are more important in driving decision making in antibiotic use for GPs, pharmacists and consumers. Findings from the Time Trade Off exercise will show what individuals are willing to trade for preserving the miracle of antibiotics. Conclusion Research findings will contribute to existing national programs to bring about a reduction in inappropriate use of antibiotic in Australia. Specifically, influencing how key messages and public health campaigns are crafted, and clinical education and empowerment of GPs and pharmacists to play a more responsive role as stewards of antibiotic use in the community.

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Measurement of fractional exhaled nitric oxide (FENO) has proven useful in assessment of patients with respiratory symptoms, especially in predicting steroid response. The objective of these studies was to clarify issues relevant for the clinical use of FENO. The influence of allergic sensitization per se on FENO in healthy asymptomatic subjects was studied, the association between airway inflammation and bronchial hyperresponsiveness (BHR) in steroid-naive subjects with symptoms suggesting asthma was examined, as well as the possible difference in this association between atopic and nonatopic subjects. Influence of smoking on FENO was compared between atopic and nonatopic steroid-naive asthmatics and healthy subjects. The short-term repeatability of FENO in COPD patients was examined in order to assess whether the degree of chronic obstruction influences the repeatability. For these purposes, we studied a random sample of 248 citizens of Helsinki, 227 army conscripts with current symptoms suggesting asthma, 19 COPD patients, and 39 healthy subjects. FENO measurement, spirometry and bronchodilatation test, structured interview. skin prick tests, and histamine and exercise challenges were performed. Among healthy subjects with no signs of airway diseases, median FENO was similar in skin prick test-positive and –negative subjects, and the upper normal limit of FENO was 30 ppb. In atopic and nonatopic subjects with symptoms suggesting asthma, FENO associated with severity of exercise- or histamine-induced BHR only in atopic patients. FENO in smokers with steroid-naive asthma was significantly higher than in healthy smokers and nonsmokers. Among atopic asthmatics, FENO was significantly lower in smokers than in nonsmokers, whereas no difference appeared among nonatopic asthmatics. The 24-h repeatability of FENO was equally good in COPD patients as in healthy subjects. These findings indicate that allergic sensitization per se does not influence FENO, supporting the view that elevated FENO indicates NO-producing airway inflammation, and that same reference range can be applied to both skin prick test-positive and -negative subjects. The significant correlation between FENO and degree of BHR only in atopic steroid-naive subjects with current asthmatic symptoms supports the view that pathogenesis of BHR in atopic asthma is strongly involved in NO-producing airway inflammation, whereas in development of BHR in nonatopic asthma other mechanisms may dominate. Attenuation of FENO only in atopic but not in nonatopic smokers with steroid-naive asthma may result from differences in mechanisms of FENO formation as well as in sensitivity of these mechanisms to smoking in atopic and nonatopic asthma. The results suggest, however, that in young adult smokers, FENO measurement may prove useful in assessment of airway inflammation. The short-term repeatability of FENO in COPD patients with moderate to very severe disease and in healthy subjects was equally good.

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Objective: Patients with atopic dermatitis often have a poor long-term response to conventional topical or systemic treatments. Staphylococcal superinfections, skin atrophy due to corticosteroid use, and asthma and allergic rhinitis are common. Only a few, usually short-term, studies have addressed the effects of different treatments on these problems. Tacrolimus ointment is the first topical compound suitable for long-term treatment. The aim of this thesis was to evaluate the effects of long-term topical tacrolimus treatment on cutaneous staphylococcal colonization, collagen synthesis, and symptoms and signs of asthma and allergic rhinitis. Methods: Patients with moderate-to-severe atopic dermatitis were treated with intermittent 0.1% tacrolimus ointment in prospective, open studies lasting for 6 to 48 months. In Study I, cutaneous staphylococcal colonization was followed for 6 to 12 months. In Study II, skin thickness and collagen synthesis were followed by skin ultrasound and procollagen I and III propeptide concentrations of suction blister fluid samples for 12 to 24 months and compared with a group of corticosteroid-treated atopic dermatitis patients and with a group of healthy subjects. Study III was a cross-sectional study of the occurrence of respiratory symptoms, bronchial hyper-responsiveness, and sputum eosinophilia in atopic dermatitis patients and healthy controls. In Study V, the same parameters as in Study III were assessed in atopic dermatitis patients before and after 12 to 48 months of topical tacrolimus treatment. Study IV was a retrospective follow-up of the effect of tacrolimus 0.03% ointment on severe atopic blepharoconjunctivitis and conjunctival cytology. Results: The clinical response to topical tacrolimus was very good in all studies (p≤0.008). Staphylococcal colonization decreased significantly, and the effect was sustained throughout the study (p=0.01). Skin thickness (p<0.001) and markers of collagen synthesis (p<0.001) increased in the tacrolimus-treated patients significantly, whereas they decreased or remained unchanged in the corticosteroid-treated controls. Symptoms of asthma and allergic rhinitis (p<0.0001), bronchial hyper-responsiveness (p<0.0001), and sputum eosinophilia (p<0.0001) were significantly more common in patients with atopic dermatitis than in healthy controls, especially in subjects with positive skin prick tests or elevated serum immunoglobulin E. During topical tacrolimus treatment the asthma and rhinitis (p=0.005 and p=0.002) symptoms and bronchial hyper-responsiveness (p=0.02) decreased significantly, and serum immunoglobulin E and sputum eosinophils showed a decreasing trend in patients with the best treatment response. Treatment of atopic blepharoconjunctivitis resulted in a marked clinical response and a significant decrease in eosinophils, lymphocytes, and neutrophils in the conjunctival cytology samples. No significant adverse effects or increase in skin infections occurred in any study. Conclusions: The studies included in this thesis, except the study showing an increase in skin collagen synthesis in tacrolimus-treated patients, were uncontrolled, warranting certain reservations. The results suggest, however, that tacrolimus ointment has several beneficial effects in the long-term intermittent treatment of atopic dermatitis. Tacrolimus ointment efficiently suppresses the T cell-induced inflammation of atopic dermatitis. It has a normalizing effect on the function of the skin measured by the decrease in staphylococcal colonization. It does not cause skin atrophy as do corticosteroids but restores the skin collagen synthesis in patients who have used corticosteroids. Tacrolimus ointment has no marked systemic effect, as the absorption of the drug is minimal and decreases along with skin improvement. The effects on the airway: decrease in bronchial hyper-responsiveness and respiratory symptoms, can be speculated to be caused by the decrease in T cell trafficking from the skin to the respiratory tissues as the skin inflammation resolves, as well as inhibition of epicutaneous invasion of various antigens causing systemic sensitization when the skin barrier is disrupted as in atopic dermatitis. Patients with moderate-to-severe atopic dermatitis seem to benefit from efficient long-term treatment with topical tacrolimus.

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Objective(s) To describe how doctors define and use the terms “futility” and “futile treatment” in end-of-life care. Design, Setting, Participants A qualitative study using semi-structured interviews with 96 doctors across a range of specialties who treat adults at the end of life. Doctors were recruited from three large Australian teaching hospitals and were interviewed from May to July 2013. Results Doctors’ conceptions of futility focused on the quality and chance of patient benefit. Aspects of benefit included physiological effect, weighing benefits and burdens, and quantity and quality of life. Quality and length of life were linked, but many doctors discussed instances when benefit was determined by quality of life alone. Most doctors described the assessment of chance of success in achieving patient benefit as a subjective exercise. Despite a broad conceptual consensus about what futility means, doctors noted variability in how the concept was applied in clinical decision-making. Over half the doctors also identified treatment that is futile but nevertheless justified, such as short-term treatment as part of supporting the family of a dying person. Conclusions There is an overwhelming preference for a qualitative approach to assessing futility, which brings with it variation in clinical decision-making. “Patient benefit” is at the heart of doctors’ definitions of futility. Determining patient benefit requires discussions with patients and families about their values and goals as well as the burdens and benefits of further treatment.

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Increased media exposure to layoffs and corporate quarterly financial reporting have created arguable a common perception – especially favored by the media itself – that the companies have been forced to improve their financial performance from quarter to quarter. Academically the relevant question is whether companies themselves feel that they are exposed to short-term pressure to perform even if it means that they have to compromise company’s long-term future. This paper studies this issue using results from a survey conducted among the 500 largest companies in Finland. The results show that companies in general feel moderate short-term pressure, with reasonable dispersion across firms. There seems to be a link between the degree of pressure felt, and the firm’s ownership structure, i.e. we find support for the existence of short-term versus long-term owners. We also find significant ownership related differences, in line with expectations, in how such short-term pressure is reflected in actual decision variables such as the investment criteria used.

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Hamiltonian systems in stellar and planetary dynamics are typically near integrable. For example, Solar System planets are almost in two-body orbits, and in simulations of the Galaxy, the orbits of stars seem regular. For such systems, sophisticated numerical methods can be developed through integrable approximations. Following this theme, we discuss three distinct problems. We start by considering numerical integration techniques for planetary systems. Perturbation methods (that utilize the integrability of the two-body motion) are preferred over conventional "blind" integration schemes. We introduce perturbation methods formulated with Cartesian variables. In our numerical comparisons, these are superior to their conventional counterparts, but, by definition, lack the energy-preserving properties of symplectic integrators. However, they are exceptionally well suited for relatively short-term integrations in which moderately high positional accuracy is required. The next exercise falls into the category of stability questions in solar systems. Traditionally, the interest has been on the orbital stability of planets, which have been quantified, e.g., by Liapunov exponents. We offer a complementary aspect by considering the protective effect that massive gas giants, like Jupiter, can offer to Earth-like planets inside the habitable zone of a planetary system. Our method produces a single quantity, called the escape rate, which characterizes the system of giant planets. We obtain some interesting results by computing escape rates for the Solar System. Galaxy modelling is our third and final topic. Because of the sheer number of stars (about 10^11 in Milky Way) galaxies are often modelled as smooth potentials hosting distributions of stars. Unfortunately, only a handful of suitable potentials are integrable (harmonic oscillator, isochrone and Stäckel potential). This severely limits the possibilities of finding an integrable approximation for an observed galaxy. A solution to this problem is torus construction; a method for numerically creating a foliation of invariant phase-space tori corresponding to a given target Hamiltonian. Canonically, the invariant tori are constructed by deforming the tori of some existing integrable toy Hamiltonian. Our contribution is to demonstrate how this can be accomplished by using a Stäckel toy Hamiltonian in ellipsoidal coordinates.

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Using US data for the period 1967:5-2002:4, this paper empirically investigates the performance of a Fed’s reaction function (FRF) that (i) allows for the presence of switching regimes, (ii) considers the long-short term spread in addition to the typical variables, (iii) uses an alternative monthly indicator of general economic activity suggested by Stock and Watson (1999), and (iv) considers interest rate smoothing. The estimation results show the existence of three switching regimes, two characterized by low volatility and the remaining regime by high volatility. Moreover, the scale of the responses of the Federal funds rate to movements in the rate of inflation and the economic activity index depends on the regime. The estimation results also show robust empirical evidence that the importance of the term spread in the FRF has increased over the sample period and the FRF has been more stable during the term of office of Chairman Greenspan than in the pre-Greenspan period.

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Published as an article in: Studies in Nonlinear Dynamics & Econometrics, 2004, vol. 8, issue 3, article 6.

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This paper considers the basic present value model of interest rates under rational expectations with two additional features. First, following McCallum (1994), the model assumes a policy reaction function where changes in the short-term interest rate are determined by the long-short spread. Second, the short-term interest rate and the risk premium processes are characterized by a Markov regime-switching model. Using US post-war interest rate data, this paper finds evidence that a two-regime switching model fits the data better than the basic model. The estimation results also show the presence of two alternative states displaying quite different features.

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Using U.S. interest rate data covering the period 1950:1-1992:7, this paper tests the rational expectations model of the term structure of interest rates. We show evidence that the rational expectations model of the term structure is supported by the data during the seventies and a period lasting from the mid-eighties to the end of the sample. However, during the …fties, sixties and a period that covers most of the Volcker’s office term (from September 1979 to April 1986) the term structure model is rejected by the data. Moreover, wefind evidence of regime changes in the short-term rate process and the term structure of interest rates. These regime switches roughly coincide with changes in the Federal Reserve chairman. The switches in monetary policy taking place when the chairmanship of the Federal Reserve changes therefore seem to play an important role in characterizing the term structure of interest rates.

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Using US data for the period 1967:5-2002:4, this paper empirically investigates the performance of an augmented version of the Taylor rule (ATR) that (i) allows for the presence of switching regimes, (ii) considers the long-short term spread in addition to the typical variables, (iii) uses an alternative monthly indicator of general economic activity suggested by Stock and Watson (1999), and (iv) considers interest rate smoothing. The estimation results show the existence of switching regimes, one characterized by low volatility and the other by high volatility. Moreover, the scale of the responses of the Federal funds rate to movements in the term spread, inflation and the economic activity index depend on the regime. The estimation results also show robust empirical evidence that the ATR has been more stable during the term of office of Chairman Greenspan than in the pre-Greenspan period. However, a closer look at the Greenspan period shows the existence of two alternative regimes and that the response of the Fed funds rate to inflation has not been significant during this period once the term spread is considered.

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Previous research has shown a strong positive correlation between short-term persistence and long-term output growth as well as between depreciation rates and long-term output growth. This evidence, therefore, contradicts the standard predictions from traditional neoclassical or AK-type growth models with exogenous depreciation. In this paper, we first confirm these findings for a larger sample of 101 countries. We then study the dynamics of growth and persistence in a model where both the depreciation rate and growth are endogenous and procyclical. We find that the model s predictions become consistent with the empirical evidence on persistence, long-term growth and depreciation rates.