Operations on large arteries; application of recent advances

With the use of anticoagulants to prevent recurrence of thrombosis it is now possible to open a major artery which has been occluded by a thrombus, remove the thickened lining with the clot and restore the continuity of the vessel. Free vein grafts have been used successfully to replace arterial segments in the extremities. Vein inlay grafts are preferred in dealing with aneurysms of the abdominal aorta. The aneurysmal wall can be used to support the venous segments. It has been possible to by-pass aneurysms of the abdominal aorta by anastomosing the splenic artery to the left iliac artery. The use of the left superficial femoral artery as a by-pass to supply blood to the right leg is described.     

Canine teeth of bats (Microchiroptera): size, shape and role in crack propagation

Upper canines in microchiropteran bats show a variety of cross-sectional shapes. A consistent feature of all species studied here is that the tooth is edged and not simply round or oval. Prominent sharp edges are positioned in several directions but particularly antero-medially toward the incisors and posteriorly toward the premolars. These edges appear to direct the cracks made in food items to the incisors or to the premolars. A continuous cutting edge is apparent in the occlusal view of the palate running from tip of canine to the ectoloph of the molars. Size and shape analysis indicates that larger bats have slender, rather than stouter, canines for their height, a condition that may be attributable to the nature of the prey. Most bats take prey that have little hard substance imbedded within. The compromises in tooth shape may vary between that of a terrestrial predator with short, conical canines for processing endoskeletal prey to that of a small flying predator with long, slender, edged canines for capturing and processing exoskeletal prey. Unicuspid teeth and how they might function in food break-up have been overlooked to the literature; such a study could lead to an understanding of how more complex teeth function.     

Distribution of Vessel Ends in Stems of some Diffuse- and Ring-porous Trees: The Nodal Regions as 'Safety Zones' of the Water Conducting System

We report measurements of the number of vessels ending withinthe nodes in comparison with that in the internodes Such measurementshave been carried out during autumn 1982 and 1983 in 1-year-oldtwigs of three species with diffuse-porous wood (Vitis vintferaL. Populus deitoides Bartr and Olea europaea L) and three ring-poroustrees (Juglans nigra L, Castanea sativa Mill, Sophora JaponicaL) In all three species with diffuse-porous wood, a significantlyhigher percentage of vessels ending in the nodes (at the leafgap) was recorded when compared with that in the internodesNo significant differences were found between nodes and internodesin this respect in ring-porous trees. Since vessel ends arecapable of screening out gaseous emboli and/or particles biggerthan 1 µm in diameter, we interpret the nodes of diffuse-poroustrees as stem zones providing safety for the water conductingsystem .The reason why ring-porous trees are likely not to needsuch ‘safety zones’ is also discussed Vitis vinifera L, grapevine, Populus deltoides Bartr, poplar, Olea europaea L, olive, Juglans nigra L, Eastern black walnut, Castanea sativa Mill, European chestnut, Sophora japonica L, Japanese pagoda tree, vessel ends, nodes, internodes     

Characterization and the broad cross‐species applicability of 20 anonymous nuclear loci isolated from the Taiwan Hwamei (Garrulax taewanus)

We isolated 20 anonymous nuclear loci (8556 bp in total) from the Taiwan Hwamei (Garrulax taewanus), an endemic songbird of Taiwan. A panel of nine to 15 individuals with unknown relationship was used to characterize polymorphism of these loci. We identified 46 single nucleotide polymorphic sites (SNPs) in 15 polymorphic loci. Frequency of SNPs was one per every 186 bp in average. Nucleotide diversity, θ, ranged from 0.00054 to 0.00371 per locus. We also tested cross‐species applicability of these loci on 17 species from eight different passerine families. All 20 loci could be successfully amplified (ranged from one to 16 species, mean = 7.9 species).     

Growth models and the expected distribution of fluctuating asymmetry

Multiplicative error accounts for much of the size-scaling and leptokurtosis in fluctuating asymmetry. It arises when growth involves the addition of tissue to that which is already present. Such errors are lognormally distributed. The distribution of the difference between two lognormal variates is leptokurtic. If those two variates are correlated, then the asymmetry variance will scale with size. Inert tissues typically exhibit additive error and have a gamma distribution. Although their asymmetry variance does not exhibit size-scaling, the distribution of the difference between two gamma variates is nevertheless leptokurtic. Measurement error is also additive, but has a normal distribution. Thus, the measurement of fluctuating asymmetry may involve the mixing of additive and multiplicative error. When errors are multiplicative, we recommend computing log  E ( l ) − log  E ( r ), the difference between the logarithms of the expected values of left and right sides, even when size-scaling is not obvious. If l and r are lognormally distributed, and measurement error is nil, the resulting distribution will be normal, and multiplicative error will not confound size-related changes in asymmetry. When errors are additive, such a transformation to remove size-scaling is unnecessary. Nevertheless, the distribution of l  −  r may still be leptokurtic.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80, 57–65.     

Microhabitat use by Blennius fluviatilis in the Río Matarraña, Spain

SUMMARY.

• 1 Microhabitat use by Blennius fluviatilis in the Río Matarraña, Spain, varied significantly among dates during a 19-month study. Most temporal variation, however, was attributable to changes in microhabitat availability.
• 2 B. fluviatilis demonstrated non-random use of available microhabitats during each sampling period, and generally occupied deeper microhabitats with higher average current velocities dominated by rubblegravel substrates.
• 3 B. fluviatilis also demonstrated non-random use of available nest sites; males generally nested under the largest available pieces of rubble, in areas with less gravel or sand. Water column depth influenced nest site use in two of four study areas.
• 4 We found few microhabitat differences between spawning and nonspawning periods, or between males and females. In addition, microhabitat use was similar among B. fluviatilis size-groups.
• 5 Although B. fluviatilis often were over-represented in deeper, erosional areas, blennies necessarily inhabited a wide range of microhabitats because average current velocities and water depths fluctuated greatly during the study. Tolerance of a broad range of environmental conditions may contribute to the species' persistence in habitats that exhibit extreme seasonal changes in discharge such as the Matarraña.

     

Ultrasound acoustic emissions from dehydrating leaves of deciduous and evergreen trees

While drying, detached leaves produced ultrasound acoustic emissions (UAE) comparable to emissions from stem and twig wood. Experiments on Ilex aquifolium L. showed that the main source of these signals was cavitation in the veins, to which conduits and fibres probably both contributed. Regions of the leaf blade with abundant mesophyll and only small veins emitted few signals. More signals were counted on the adaxial side of the midrib than on the abaxial one and on the proximal third than on the distal one, in accordance with the anatomical structure. Sound attenuation was pronounced. Eight species were compared with respect to cavitation behaviour, field water relations and pressure–volume curves, and the data showed differences in cumulative number of events and resistance of leaves to cavitation. Data were generally in good agreement with anatomical structure and habitat preferences. The number of signals per conduit counted on cross-sections was in some leaves much higher than unity, which suggests short xylem elements or an acoustic activity of cells other than conduits. There was no correlation between cavitation threshold or cumulative number of signals and the degree of sclerophylly; unexpectedly, there was a correlation between the cumulative number of signals at a water potential of -1.3 MPa and the bulk modulus of elasticity.