In endoprosthesis surgery there are typically a high percentage of implant defects, these can lead to failure of the whole prosthesis. One type of total hip replacement function loss is acetabular cup loosening from the pelvic bone. This article examines manufacture perturbations as one of the possible reasons for this kind of failure. Both dimension and geometry manufacturing perturbations of ceramic head and polyethylen cup were analyzed. We find that perturbations in the variables analysed here affect considered values of contact pressure and frictional moment. Furthermore, contact pressure and frictonal moment are quantities affecting replacement success and durability. From obtained results we can recommend to fit head and cup with a clearance of between 0 mm andd 0.05 mm. We do not recommend using interference type of fit. Roundness perturbation of ceramic head should not exceed 0.025 mm. and Obsahuje seznam literatury
The responses of growth and leaf gas exchange to increasing salinity were measured in two halophytes [Atriplex nummularia (C4), Atriplex hastata (C3)] and one glycophyte [Hordeum vulgare (C3)]. The growth (dry mass) of both the halophytes was significantly increased, by 54 and 17 %, respectively, as salinity was increased in the range 0-200 mol m-^ NaCl. However, net CO2 assimilation rate (Pn)- the intercellular CO2 concentration (Cj) and leaf conductance (^1) were unaffected. At higher levels of salinity (in the range 400 - 600 mol m"^ NaCl) the growth of the two halophytes was severely reduced (by 44 and 51 %, respectively). At these levels of salinity q were significantly depressed. 25 mol m*^ NaCl significantly reduced the growth of H. vulgare by 44 %, but had no effect on Py^, g| and Cj. However, at 100 mol m'^ NaCl, where growth was decreased by 62 %, and g| were significantly reduced while q was unaltered. There was thus, no association between the effects of salinity on growth and leaf gas exchange at low salinities (25- 200 mol m'3 NaCl). At higher salinities, leaf gas exchange and growth were both severely inhibited but it is unlikely that a direct causal relationship existed. At these salinities sodium concentration in the leaves (tissue water basis) was above 400 mol m'3 in the halophytes and above 100 mol m'^ in H. vulgare which possibly affected both growth and leaf gas exchange independently. Also, the effects of salinity on total leaf chlorophyll concentration and net CO2 assimilation rate expressed on a chlorophyll (chl) basis (Pchi) were no better related to growth than was Pn
Soil sealing is the permanent covering of the land surface by buildings, infrastructures or any impermeable artificial material. Beside the loss of fertile soils with a direct impact on food security, soil sealing modifies the hydrological cycle. This can cause an increased flooding risk, due to urban development in potential risk areas and to the increased volumes of runoff. This work estimates the increase of runoff due to sealing following urbanization and land take in the plain of Emilia Romagna (Italy), using the Green and Ampt infiltration model for two rainfall return periods (20 and 200 years) in two different years, 1976 and 2008. To this goal a hydropedological approach was adopted in order to characterize soil hydraulic properties via locally calibrated pedotransfer functions (PTF). PTF inputs were estimated via sequential Gaussian simulations coupled with a simple kriging with varying local means, taking into account soil type and dominant land use. Results show that in the study area an average increment of 8.4% in sealed areas due to urbanization and sprawl induces an average increment in surface runoff equal to 3.5 and 2.7% respectively for 20 and 200-years return periods, with a maximum > 20% for highly sealed coast areas.
A graph is called magic (supermagic) if it admits a labelling of the edges by pairwise different (consecutive) positive integers such that the sum of the labels of the edges incident with a vertex is independent of the particular vertex. We characterize magic line graphs of general graphs and describe some class of supermagic line graphs of bipartite graphs.