Integrating high and moderate spatial resolution image data to estimate forest age structure

The collection of spatial information to quantify changes to the state and condition of the environment is a fundamental component of conservation or sustainable utilization of tropical and subtropical forests, Age is an important structural attribute of old-growth forests influencing biological diversity in Australia eucalypt forests. Aerial photograph interpretation has traditionally been used for mapping the age and structure of forest stands. However this method is subjective and is not able to accurately capture fine to landscape scale variation necessary for ecological studies. Identification and mapping of fine to landscape scale vegetative structural attributes will allow the compilation of information associated with Montreal Process indicators lb and ld, which seek to determine linkages between age structure and the diversity and abundance of forest fauna populations. This project integrated measurements of structural attributes derived from a canopy-height elevation model with results from a geometrical-optical/spectral mixture analysis model to map forest age structure at a landscape scale. The availability of multiple-scale data allows the transfer of high-resolution attributes to landscape scale monitoring. Multispectral image data were obtained from a DMSV (Digital Multi-Spectral Video) sensor over St Mary's State Forest in Southeast Queensland, Australia. Local scene variance levels for different forest tapes calculated from the DMSV data were used to optimize the tree density and canopy size output in a geometric-optical model applied to a Landsat Thematic Mapper (TU) data set. Airborne laser scanner data obtained over the project area were used to calibrate a digital filter to extract tree heights from a digital elevation model that was derived from scanned colour stereopairs. The modelled estimates of tree height, crown size, and tree density were used to produce a decision-tree classification of forest successional stage at a landscape scale. The results obtained (72% accuracy), were limited in validation, but demonstrate potential for using the multi-scale methodology to provide spatial information for forestry policy objectives (ie., monitoring forest age structure).

Age changes in personality traits and their heritabilities during the adult years: evidence from Australian Twin Registry samples

Short versions of four Eysenck personality scales had been included in questionnaires given to several adult samples from the Australian Twin Registry, comprising altogether some 5400 pairs. Means and regressions with age are compared for three samples at average ages of 23, 37, and 61 years, and for two samples of retested individuals, one tested twice at average ages of 29 and 37 years, and one tested three times at average ages of 45, 56, and 62 years, For both males and females the trends for Psychoticism (P), Extraversion (E), and Neuroticism (N) were generally downward with age, and for Lie (L), upward. However, in the longitudinal sample between ages 56 and 62 the trends for P, E, and I stopped or reversed, although N continued downward. Heritabilities were reasonably stable across age for P, E, and N, and the effects of shared environments negligible, but L showed some influence of shared environment as well as genes in all but the oldest age group. (C) 2001 Elsevier Science Ltd. All rights reserved.

Living with osteoarthritis: Patient expenditures, health status, and social impact

Objective. To determine out-of-pocket expenditures related to osteoarthritis (OA) and to explore whether demographic details, health status scores (Medical Outcomes Study 36-item Short Form [SF-36] and Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), or perception of social effect were expenditure determinants. Methods. A prospective cohort study of community-dwelling subjects with OA completed 4 consecutive 3-month cost diaries. In addition, subjects completed the SF-36 and WOMAC at baseline and at 12 months. Social impact at baseline was collected. Four groups categorized by age and sex were compared. Patients undergoing joint replacement were excluded. Results. Differences in health status were defined more by age than by sex, especially for physical function. The costs to the patients were high, particularly for women, who spent more on medications and special equipment. Women also reported receiving more assistance from family and friends. Higher disease-related expenditures were associated with greater pain levels, poorer social function and mental health, and longer duration of disease. Significant independent predictors of total patient expenditures related to OA were being female and having joint stiffness. Conclusion. Despite having heavily subsidized health care and access to the Pharmaceutical Benefits Scheme, out-of-pocket costs for patients with OA in Australia are considerable. Higher expenditures for patients with OA are related to more advanced disease, especially for women.

Older adults' trait ratings of three age groups around the Pacific rim

In this paper, we assess the traits that older adultsassociate with younger, middle-aged, and older adults in fivePacific Rim nations from Western and Eastern cultural traditions(Australia, People's Republic of China (PRC), Hong Kong,Philippines, Thailand). We find cross-cultural trends whichreplicate patterns found in the US context. In most cultures,attractiveness, strength, activity, liberalism, health, andflexibility are seen to decline with increasing age. Kindnessassessments are positively associated with age across cultures. Mixed patterns are found with assessments of wisdom andgenerosity, with respondents from the PRC and Hong Kong beingnotably more negative about increasing age than otherrespondents. Implications for the aging process across culturesare discussed, and suggestions made for future research.

Class I histone deacetylases sequentially interact with MyoD and pRb during skeletal myogenesis

We describe a functional and biochemical link between the myogenic activator MyoD, the deacetylase HDAC1, and the tumor suppressor pRb. Interaction of MyoD with HDAC1 in undifferentiated myoblasts mediates repression of muscle-specific gene expression. Prodifferentiation cues, mimicked by serum removal, induce both downregulation of HDAC1 protein and pRb hypophosphorylation. Dephosphorylation of pRb promotes the formation of pRb-HDAC1 complex in differentiated myotubes. pRb-HDAC1 association coincides with disassembling of MyoD-HDAC1 complex, transcriptional activation of muscle-restricted genes, and cellular differentiation of skeletal myoblasts. A single point mutation introduced in the HDAC1 binding domain of pRb compromises its ability to disrupt MyoD-HDAC1 interaction and to promote muscle gene expression. These results suggest that reduced expression of HDAC1 accompanied by its redistribution in alternative nuclear protein complexes is critical for terminal differentiation of skeletal muscle cells.

Dietary and supplement treatment of iron deficiency results in improvements in general health and fatigue in Australian women of childbearing age

Objective: To examine the effects of iron deficiency and its treatment by iron supplementation or a high iron diet on fatigue and general health measures in women of childbearing age. Design: Randomised controlled trial to compare supplement and dietary treatment of iron deficiency. Subjects: 44 iron deficient (serum ferritin < 15 mug/L or serum ferritin 15-20 mug/L, plus two of the following: serum iron < 10 mu mol/L, total iron binding capacity > 68 mu mol/L or transferrin saturation < 15%) and 22 iron replete (hemoglobin greater than or equal to 120 g/L and serum ferritin > 20 mug/L) women 18 to 50 years of age were matched for age and parity. Interventions: Iron deficient women were randomly allocated to either iron supplementation or a high iron diet for 12 weeks. Measures of Outcome: Iron deficient and iron replete participants had iron studies performed and completed the Piper Fatigue Scale (PFS) and the SF-36 general health and well-being questionnaire at baseline (TO), following the 12 week intervention (TI) and again after a six-month non-intervention phase (T2). The SF-36 includes measures of physical (PCS) and mental (MCS) health and vitality (VT). Results: MCS and VT scores were lower and PFS scores were higher for iron deficient women (diet and supplement groups) than iron replete women at baseline. Both intervention groups showed similar improvements in MCS, VT and PFS scores during the intervention phase, but mean increases in serum ferritin were greater in the supplement than the diet group. PCS scores were not related to iron status. Conclusions: Treatment of iron deficiency with either supplementation or a high iron diet results in improved mental health and decreased fatigue among women of childbearing age.

Dietary treatment of iron deficiency in women of childbearing age

Background: The Australian Iron Status Advisory Panel advocates dietary intervention as the first treatment option for mild iron deficiency [serum ferritin (SF) = 10-15 mug/L]. However, there appear to be no studies on the efficacy of dietary treatment for iron deficiency. Objective: We compared the effects of iron supplementation and of a high-iron diet on serum ferritin (SF) and hemoglobin in iron-deficient women of childbearing age. Design: Forty-four iron-deficient women (SF < 15 mug/L or SF = 15-20 mug/L plus serum iron < 10 mu mol/L and total-iron-binding capacity > 68 mu mol/L) and 22 iron-replete women (hemoglobin greater than or equal to 120 g/L and SF > 20 mug/L) matched for age and parity categories were enrolled and completed 7-d weighed food records at baseline. The iron-deficient women were randomly allocated to receive iron supplementation (105 mg/d; supplement group) or a high-iron diet (recommended intake of absorbable iron: 2.25 mg/d; diet group) for 12 wk. Hematologic and dietary assessments were repeated at the end of the intervention and again after a 6-mo follow-up. Results: Mean SF in the supplement group increased from 9.0 +/- 3.9 mug/L at baseline to 24.8 +/- 10.0 mug/L after the intervention and remained stable during follow-up (24.2 +/- 9.8 mug/L whereas the diet group had smaller increases during the intervention (8.9 +/- 3.1 to 11.0 +/- 5.9 mug/L) but continued to improve during follow-up (to 15.2 +/- 9.5 mug/L). Mean hemoglobin tended to improve in both intervention groups, but the change was only significant in the supplement group. Conclusions: In iron-deficient women of childbearing age, a high-iron diet produced smaller increases in SF than did iron supplementation but resulted in continued improvements in iron status during a 6-mo follow-up.

Effects of vitamin E and alpha-lipoic acid on skeletal muscle contractile properties

Initial experiments were conducted using an in situ rat tibialis anterior (TA) muscle preparation to assess the influence of dietary antioxidants on muscle contractile properties. Adult Sprague-Dawley rats were divided into two dietary groups: 1) control diet (Con) and 2) supplemented with vitamin E (VE) and alpha -lipoic acid (alpha -LA) (Antiox). Antiox rats were fed the Con rats' diet (AIN-93M) with an additional 10,000 IU VE/kg diet and 1.65 g/kg alpha -LA. After an 8-wk feeding period, no differences existed (P > 0.05) between the two dietary groups in maximum specific tension before or after a fatigue protocol or in force production during the fatigue protocol. However, in unfatigued muscle, maximal twitch tension and tetanic force production at stimulation frequencies less than or equal to 40 Hz were less (P < 0.05) in Antiox animals compared with Con. To investigate which antioxidant was responsible for the depressed force production, a second experiment was conducted using an in vitro rat diaphragm preparation. Varying concentrations of VE and dihydrolipoic acid, the reduced form of -LA, were added either individually or in combination to baths containing diaphragm muscle strips. The results from these experiments indicate that high levels of VE depress skeletal muscle force production at low stimulation frequencies.

Long-term metabolic and skeletal muscle adaptations to short-sprint training: Implications for sprint training and tapering

The adaptations of muscle to sprint training can be separated into metabolic and morphological changes. Enzyme adaptations represent a major metabolic adaptation to sprint training, with the enzymes of all three energy systems showing signs of adaptation to training and some evidence of a return to baseline levels with detraining. Myokinase and creatine phosphokinase have shown small increases as a result of short-sprint training in some studies and elite sprinters appear better able to rapidly breakdown phosphocreatine (PCr) than the sub-elite. No changes in these enzyme levels have been reported as a result of detraining. Similarly, glycolytic enzyme activity (notably lactate dehydrogenase, phosphofructokinase and glycogen phosphorylase) has been shown to increase after training consisting of either long (> 10-second) or short (< 10-second) sprints. Evidence suggests that these enzymes return to pre-training levels after somewhere between 7 weeks and 6 months of detraining. Mitochondrial enzyme activity also increases after sprint training, particularly when long sprints or short recovery between short sprints are used as the training stimulus. Morphological adaptations to sprint training include changes in muscle fibre type, sarcoplasmic reticulum, and fibre cross-sectional area. An appropriate sprint training programme could be expected to induce a shift toward type Ha muscle, increase muscle cross-sectional area and increase the sarcoplasmic reticulum volume to aid release of Ca2+. Training volume and/or frequency of sprint training in excess of what is optimal for an individual, however, will induce a shift toward slower muscle contractile characteristics. In contrast, detraining appears to shift the contractile characteristics towards type IIb, although muscle atrophy is also likely to occur. Muscle conduction velocity appears to be a potential non-invasive method of monitoring contractile changes in response to sprint training and detraining. In summary, adaptation to sprint training is clearly dependent on the duration of sprinting, recovery between repetitions, total volume and frequency of training bouts. These variables have profound effects on the metabolic, structural and performance adaptations from a sprint-training programme and these changes take a considerable period of time to return to baseline after a period of detraining. However, the complexity of the interaction between the aforementioned variables and training adaptation combined with individual differences is clearly disruptive to the transfer of knowledge and advice from laboratory to coach to athlete.