Supporting cystic fibrosis disease management during adolescence: the role of family and friends.

BACKGROUND: Successful management of a complex disease, such as cystic fibrosis (CF), requires support from family and friends; however, few studies have examined social support in adolescents with CF. METHODS: Twenty-four adolescents were interviewed about the support they receive from family and friends. Interviews were transcribed, coded and analysed to determine the types, frequency and perceived supportiveness of specific behaviours. RESULTS: Both family and friends provided treatment-related support to adolescents with CF. Family provided more tangible support and friends provided more relational support. Adolescents also reported that the manner, timing and context of support behaviours influenced their perceptions of the behaviours' supportiveness. A subset of adolescents (17%) chose not to disclose their diagnosis to their friends. CONCLUSIONS: The provision of support appears to be distinct from adolescent's perception of support and there may be some behaviours, such as treatment reminders, that are important to disease management but viewed as less supportive by adolescents. Facilitating increased social support holds the promise of improving disease management during adolescents, but more work is need to understand which aspects of support are related to management outcomes.

Enhanced monsoon precipitation and nitrogen deposition affect leaf traits and photosynthesis differently in spring and summer in the desert shrub Larrea tridentata.

Leaf-level CO2 assimilation (A(area)) can largely be predicted from stomatal conductance (g(s)), leaf morphology (SLA) and nitrogen (N) content (N(area)) in species across biomes and functional groups. The effects of simulated global change scenarios, increased summer monsoon rain (+H2O), N deposition (+N) and the combination (+H2O +N), were hypothesized to affect leaf trait-photosynthesis relationships differently in the short- and long-term for the desert shrub Larrea tridentata. During the spring, +H2O and +H2O +N plants had lower A(area) and g(s), but similar shoot water potential (Psi(shoot)) compared with control and +N plants; differences in A(area) were attributed to lower leaf N(area) and g(s). During the summer, +H2O and +H2O +N plants displayed higher A(area) than control and +N plants, which was attributed to higher Psi(shoot), g(s) and SLA. Throughout the year, A(area) was strongly correlated with g(s) but weakly correlated with leaf N(area) and SLA. We concluded that increased summer monsoon had a stronger effect on the performance of Larrea than increased N deposition. In the short term, the +H2O and +H2O +N treatments were associated with increasing A(area) in summer, but also with low leaf N(area) and lower A(area) in the long term the following spring.

The xanthophyll cycle and energy dissipation in differently oriented faces of the cactus Opuntia macrorhiza.

 Diurnal changes in titratable acidity, photosynthesis, energy dissipation activity, and the carotenoid composition of differently oriented cladodes of the cactus Opuntia macrorhiza were characterized during exposure to full sunlight in the field. Four cladode faces were chosen such that each was exposed to maximum photon flux densities (PFD) at different times of the day in addition to receiving different daily integrated PFDs. The sum of all carotenoids per chlorophyll was found to increase with increasing exposure to PFD, with the carotenoids of the xanthophyll cycle present in the most exposed face at more than twice the concentration found in the least exposed face. All faces exhibited large increases in xanthophyll cycle-dependent energy dissipation as the sun rose in the morning, even those receiving only minimal levels of diffuse radiation. The transient high levels of energy dissipation in those faces that did not receive direct sunlight in the morning may have been due to low temperature inhibition of photosynthesis (predawn low of 2°C). For the two faces receiving peak PFDs in the morning hours (north and east faces), the level of energy dissipation activity increased rapidly during exposure to direct sunlight in the early morning, gradually declining in the late morning under warm temperatures, and was negligible during the afternoon low light conditions. Changes in the xanthophyll cycle paralleled the changes in energy dissipation with the majority of the cycle present as violaxanthin (V) prior to sunrise, largely de-epoxidized to zeaxanthin (Z) and antheraxanthin (A) during exposure to direct sunlight, and reconverted to V during the afternoon. For the two faces receiving peak PFDs in the afternoon (south and west faces), energy dissipation activity increased dramatically during the early morning low light period, subsequently decreasing during midday as decarboxylation of malic acid proceeded maximally (providing a high concentration of CO2 for photosynthesis), and then increased to the highest level in the late afternoon as the supply of malic acid was depleted and rates of photosynthetic electron transport declined. The xanthophyll cycle, largely present as Z and A prior to sunrise in the south and west faces, was de-epoxidized to the greatest extent in the late afternoon, followed by epoxidation back to the predawn level by sunset. In all cladode faces high levels of energy dissipation activity were accompanied by decreases in the intrinsic efficiency of photosystem II (PSII), indicative of a regulatory process that diverted the excess energy away from the reaction centers during periods of excess light. Furthermore, the overnight retention of Z and A by the south and west faces was accompanied by a sustained reduction in PSII efficiency (i.e., "photoinhibition"). We suggest that this "photoinhibition" represents the sustained engagement of nocturnally retained Z and A in the photoprotective down-regulation of PSII.

Far infrared imagery.

Active imaging experiments are described in the 300 microm-l mm-region of the far infrared (FIR) spectrum. Transmission data are presented for a wide variety of common materials indicating the range of applicability of FIR imaging to law enforcement or nondestructive testing. The FIR images of several objects are presented, and the practicality of FIR imaging is discussed in light of straightforward improvements that can be made in the simple imaging system employed in these studies.