1000 resultados para Long-Term Potentiation


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Life history theory predicts that individuals make trade-offs between investment in current reproduction, future reproductive potential and success in order to maximise lifetime reproductive success (LRS). Factors that may influence LRS in seabirds include delayed maturity, small clutches, high adults survivorship and long life spans. Studies have shown that reproductive success of seabirds increases with age and experience. Australasian gannets are long-lived seabirds that typically commence breeding at five or six years of age. A small colony of gannets was monitored over 12 years. This study aimed to identify patterns of long-term individual breeding biology. Results indicate that nest site, pair bond duration, age and breeding experience are all important factors in reproductive success. Relationships were found between breeding success and several variables including breeding experience, pair bond duration and nest site quality. Identifying and understanding the factors that contribute to individuals’ reproductive success is of critical importance for future conservation and management of seabird species.

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With an increasing demand and reliance on volunteers in a host of different sectors, the need for organisations to understand motivating factors behind volunteering, and how to retain volunteer services, is crucial. This paper examines the recruitment, retention and attrition among a group of volunteers participating in a long-term monitoring program for the critically endangered orange-bellied parrot Neophema chrysogaster. This project is one of the longest running of its type in Australia with more than 20 years of survey activities. Volunteers were most often recruited via other environmental agencies. Almost three-quarters of respondents had been involved in birdwatching or other bird monitoring activities usually in connection with conservation organisations. The modal response was an involvement of 10-20 years, with most other responses in the range 0-5 years. The majority intend to continue volunteering, but cited perceived health and time commitments as the main factors behind possible future decisions to cease volunteering. Respondents suggested improvements in the volunteer management of the program, and in particular, thought a personal 'thank you', would maintain motivation and participation.

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A variety of nutrition screening instruments have been developed and implemented for identifying the risk of undernutrition among community and hospitalized older adults. Despite the high prevalence of undernutrition amongst older adults in long-term care, few screening instruments have been developed or evaluated in this setting. This review aims to evaluate the validity, reproducibility and feasibility of nutrition screening instruments developed for use, or described as being used, with older adults in long-term care. Ten publications encompassing nine independent nutrition screening tools were identified using electronic databases and manual searches of reference lists. The Mini Nutritional Assessment-Short Form (MNA-SF) was the most widely evaluated nutrition screening instrument and met the requirements for a valid instrument (sensitivity and specificity >0.9) for use in the long-term care setting. Modified versions of the MNA for use in China and South Africa also demonstrated acceptable levels of sensitivity and specificity. Other nutrition screening instruments were found to have variable levels of sensitivity and specificity and while some demonstrated levels consistent with the MNA-SF, only two were evaluated across more than one study population, Body Mass Index (BMI)+weight loss and BMI+albumin. These same instruments reported the highest levels of inter-rater and test-retest reproducibility, although this was only tested in one other instrument (Chinese Nutrition Screen -modified MNA). In conclusion, it is evident from this review that further work in this area is needed. Based on validity, reproducibility and feasibility it appears that BMI+weight loss is the most suitable nutrition screening instrument for use in the long-term care setting at this time. MNA-SF is promising; however, there is currently no data for inter-rater or test-retest reproducibility in the long-term care setting.

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Background
Studies support the positive effects that Tai Chi has on the physical health of older adults. However, many older adults residing in long-term care facilities feel too weak to practice traditional Tai Chi, and a more simplified style is preferred.
Objective
To test the effects of a newly-developed, Simplified Tai-Chi Exercise Program (STEP) on the physical health of older adults who resided in long-term care facilities.
Design
A single group design with multiple time points: three pre-tests, one month apart; four post-tests at one month, two months, three months, and six months after intervention started.
Settings
Two 300–400 bed veteran homes in Taiwan.
Participants
The 51 male older adults were recruited through convenience sampling, and 41 of them completed six-month study. Inclusion criteria included: (1) aged 65 and over; (2) no previous training in Tai Chi; (3) cognitively alert and had a score of at least eight on the Short Portable Mental Status Questionnaire; (4) able to walk without assistance; and (5) had a Barthel Index score of 61 or higher. Participants who had dementia, were wheel-chair bound, or had severe or acute cardiovascular, musculoskeletal, or pulmonary illnesses were excluded.
Methods
The STEP was implemented three times a week, 50 min per session for six months. The outcome measures included cardio-respiratory function, blood pressure, balance, hand-grip strength, lower body flexibility, and physical health actualization.
Results
A drop in systolic blood pressure (p=.017) and diastolic blood pressure (p<.001) was detected six months after intervention started. Increase in hand-grip strength from pre to post intervention was found (left hand: p<.001; right hand: p=.035). Participants also had better lower body flexibility after practicing STEP (p=.038).
Conclusions
Findings suggest that the STEP be incorporated as a floor activity in long-term care facilities to promote physical health of older adults.

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Abstract - Parks Victoria manages Victoria's (Australia) national, state and urban parks. These parks make up approximately 17% of the state's area and annually receive 45.3 million visits. Parks Victoria has been dedicated to the development of scientifically sound methods for monitoring visitors and the community since 1994. The three main ongoing monitoring streams are: visit quantities, community perceptions of management and visitor experience (Visitor Satisfaction Monitor). Accumulated research data from the Visitor Satisfaction Monitor (VSM) has been used to profile and refine the organisation's understanding of its various park visitors. After 10 years that data has matured to produce a comprehensive visitor-product market segmentation. Over 11,000 interviews at 34 major parks (including 68 visitor sites) between 2000 and 2004 were used to group park visitors into seven segments. The segments are Nature Admirers, Urban Socials Trail Users, Passives and Other Users, Activity Centrics, Access Made Easy and Country Vacationers. Each park visitor segment, or group, had substantial differences from the other groups, while the individuals within each segment had much more in common; Nature Admirers visit in small groups for a short spectacular scenic experience whereas Urban Socials visit in large groups for half-day social interactions such as birthday parties and picnics. Further analyses have been conducted to identify individual sub-segments within each of the major segments. These sub-segments provide detailed information that can be used for the future development of parks and associated services. Subsequent analysis using Structural Equation Modelling provides evidence that the relationships between services and satisfaction are better understood when considering segments. Parks Victoria has been using segments in park management applications such as wild fire recovery plans, tourism strategy formulation, park management planning and visitor risk management. It has proved to be an efficient and effective systematic way of meeting visitor needs.

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Objective: This study assesses the long-term cost-effectiveness of a comprehensive model of mental health care for first-episode psychosis. The study is an extension of a previous economic evaluation of the Early Psychosis Prevention and Intervention Centre (EPPIC) that assessed the first-year costs and outcomes of treatment.

Method: The current study used a matched, historical control group design with a follow-up of approximately 8 years. Complete follow-up data were available for 65 of the original 102 participants. Direct public mental health service costs incurred subsequent to the first year of treatment and symptomatic and functional outcomes of 32 participants initially treated for up to 2 years at EPPIC were compared with a matched cohort of 33 participants initially treated by generic mental health services. Treatment-related resource use was measured and valued using Australian published prices.

Results: Almost 8 years after initial treatment, EPPIC subjects displayed lower levels of positive psychotic symptoms (P = .007), were more likely to be in remission (P = .008), and had a more favorable course of illness (P = .011) than the controls. Fifty-six percent of the EPPIC cohort were in paid employment over the last 2 years compared with 33% of controls (P = .083). Each EPPIC patient costs on average A$3445 per annum to treat compared with controls, who each costs A$9503 per annum.

Conclusions: Specialized early psychosis programs can deliver a higher recovery rate at one-third the cost of standard public mental health services. Residual methodological limitations and limited sample size indicate that further research is required to verify this finding.

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Background/Objectives:
Some epidemiological and clinical studies have shown that increased dairy consumption or calcium and/or vitamin D supplementation can have a beneficial effect on blood pressure, and lipid and lipoprotein concentrations. The aim of this study was to assess the long-term effects of calcium-vitamin D3 fortified milk on blood pressure and lipid-lipoprotein concentrations in community-dwelling older men.

Subjects/Methods:
This is a substudy of a 2-year randomized controlled trial in which 167 men aged >50 years were assigned to receive either 400 ml per day of reduced fat (approx1%) milk fortified with approximately 1000 mg of calcium and 800 IU of vitamin D3 or to a control group receiving no additional fortified milk. Weight, blood pressure, lipid and lipoprotein concentrations were measured every 6 months. Participants on lipid-lowering (n=32) or antihypertensive medication (n=39) were included, but those who commenced, increased or decreased their medication throughout the intervention were excluded (n=27).

Results:
In the 140 men included in this study (milk, n=73; control, n=67), there were no significant effects of the calcium-vitamin D3 fortified milk on weight, systolic or diastolic blood pressure, total cholesterol, high-density lipoprotein or low-density lipoprotein cholesterol or triglyceride concentrations at any time throughout the intervention. Similar results were observed after excluding men taking antihypertensive or lipid-lowering medication or limiting the analysis to those with baseline calcium intakes <1000 mg per day and/or with hypovitaminosis D (25(OH)D <75 nmol/l).

Conclusions:
Supplementation with reduced-fat calcium-vitamin D3 fortified milk did not have a beneficial (nor detrimental) effect on blood pressure, lipid or lipoprotein concentrations in healthy community-dwelling older men.

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In a cross-sectional study, we determined whether results from the Mini Nutritional Assessment (MNA), Geriatric Depression Scale (GDS), and Katz Activities of Daily Living (ADL), were associated with nutritional status and mobility in long-term care residents. One hundred and fifteen study participants (mean [SD] age: 80.2 [10.6]) provided informed consent. Fifty eight percent (n = 66) responded to all three questionnaires: 12 were assessed as malnourished (MNA < 17) and 28 were depressed (GDS ≥ 6). Higher levels of depression were associated with lower serum zinc (n = 71, r = -.356, p = .001) and associated with a slower Timed Up and Go test (TUG, n = 38, r = .301, p = .030). MNA was also associated with serum zinc (n = 44, r = .307, P = .021). Non responders to questionnaires (n = 36) had a lower BMI (mean difference: -2.5 ± 1.0 kg/m2, p = .013) and serum 25(OH)D (-8.7 ± 3.8 nmol/l, p = .023) vs. responders. The GDS, in addition to the MNA, is useful in identifying poor nutritional status in residential care. Intervention programs that target depression and poor nutritional status could potentially improve overall quality of life, but it is not clear if depression is leading to poor nutritional status or if poor nutrition is leading to depression.

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The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p < 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81 - 0.84, p < 0.0001). The correlations were still significant after adjusting for whole-body BMC body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.

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The benefit of impact-loading activity for bone strength depends on whether the additional bone mineral content (BMC) accrued at loaded sites is due to an increased bone size, volumetric bone mineral density (vBMD) or both. Using magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DXA), the aim of this study was to characterize the geometric changes of the dominant radius in response to long-term tennis playing and to assess the influence of muscle forces on bone tissue by investigating the muscle–bone relationship. Twenty tennis players (10 men and 10 women, mean age: 23.1 ± 4.7 years, with 14.3 ± 3.4 years of playing) were recruited. The total bone volume, cortical volume, sub-cortical volume and muscle volume were measured at both distal radii by MRI. BMC was assessed by DXA and was divided by the total bone volume to derive vBMD. Grip strength was evaluated with a dynamometer. Significant side-to-side differences (P < 0.0001) were found in muscle volume (+9.7%), grip strength (+13.3%), BMC (+13.5%), total bone volume (+10.3%) and sub-cortical volume (+20.6%), but not in cortical volume (+2.6%, ns). The asymmetry in total bone volume explained 75% of the variance in BMC asymmetry (P < 0.0001). vBMD was slightly higher on the dominant side (+3.3%, P < 0.05). Grip strength and muscle volume correlated with all bone variables (except vBMD) on both sides (r = 0.48–0.86, P < 0.05–0.0001) but the asymmetries in muscle parameters did not correlate with those in bone parameters. After adjustment for muscle volume or grip strength, BMC was still greater on the dominant side. This study showed that the greater BMC induced by long-term tennis playing at the dominant radius was associated to a marked increase in bone size and a slight improvement in volumetric BMD, thereby improving bone strength. In addition to the muscle contractions, other mechanical stimuli seemed to exert a direct effect on bone tissue, contributing to the specific bone response to tennis playing.

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Mechanical loading during growth magnifies the normal increase in bone diameter occurring in long bone shafts, but the response to loading in long bone ends remains unclear. The aim of the study was to investigate the effects of tennis playing during growth at the distal radius, comparing the bone response at trabecular and cortical skeletal sites. The influence of training duration was examined by studying bone response in short-term (children) and long-term (young adults) perspectives. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the radius were measured by DXA in 28 young (11.6 ± 1.4 years old) and 47 adult tennis players (22.3 ± 2.7 years old), and 70 age-matched controls (12 children, 58 adults) at three sites: the ultradistal region (trabecular), the mid-distal region, and the third-distal region (cortical). At the ultradistal radius, young and adult tennis players displayed similar side-to-side differences, the asymmetry in BMC reaching 16.3% and 13.8%, respectively (P < 0.0001). At the mid- and third-distal radius, the asymmetry was much greater in adults than in children (P < 0.0001) for all the bone parameters (mid-distal radius, +6.6% versus +15.6%; third-distal radius, +6.9% versus +13.3%, for BMC). Epiphyseal bone enduring longitudinal growth showed a great capacity to respond to mechanical loading in children. Prolonging tennis playing into adulthood was associated with further increase in bone mineralization at diaphyseal skeletal sites. These findings illustrate the benefits of practicing impact-loading sports during growth and maintaining physical activity into adulthood to enhance bone mass accrual and prevent fractures later in life.