Abstract.— Phylogenetic inertia is a difficult issue in evolutionary biology because we have yet to reach a consensus about how to measure it. In this study a comparative approach is used to evaluate phylogenetic inertia in 14 demographic and morphological characters in 10 species and one subspecies of the genus Tithonia (Asteraceae). Three different methods, autocorrelational analysis, phylogenetic correlograms, and ancestor-state reconstruction, were used to evaluate phylogenetic inertia in these traits. Results were highly dependent on the method applied. Autoregression and phylogenetic eigenvector regression (PVR) methods found more inertia in morphological traits. In contrast, phylogenetic correlograms and ancestor-state reconstruction suggest that morphological characters exhibit less phylogenetic inertia than demographic ones. The differences between results are discussed and methods are compared in an effort to understand phylogenetic inertia more thoroughly. 相似文献
To show the relationships of calcium accumulation in the thoracic aorta to the other tissues, calcium contents were determined
with a microwave-induced plasma-atomic emission spectrometer on arteries, veins, cartilages, ligaments, and bones. These tissues
were resected from 18 individuals, consisting of 11 men and 7 women who died in the age range 59–91 yr. As thoracic and abdominal
aortas are routinely used for radiographic examination of arterial calcification, they appear to be standard tissues of the
calcium accumulation. The calcium accumulations were determined in the femoral artery, the superior and inferior venae cavae,
the internal jugular vein, cartilages of the articular disk of the temporomandibular joint and the intervertebral disk, both
the ligaments of the anterior cruciate ligament and the ligamentum capitis femoris, and the calcaneus, in contrast with the
thoracic aorta.
As calcium increased in the thoracic aorta, it increased in the femoral artery, the articular disk of the temporomandibular
joint, the intervertebral disk, both ligaments of the anterior cruciate ligament, and the ligamentum capitis femoris, but
it did not increase in veins, such as the superior and inferior venae cavae and the internal jugular vein. In contrast, it
decreased in the calcaneus. 相似文献
Ossification of the posterior longitudinal ligament of the spine (OPLL) is recognized as a common disorder among Japanese and throughout Asia. Estimates of its prevalence are in the range of 1. 9%-4.3%. Although its etiology is thought to involve a multiplicity of factors, epidemiological and family studies strongly implicate genetic susceptibility in the pathogenesis of OPLL. In this study we report an identification of a predisposing locus for OPLL, on chromosome 6p, close to the HLA complex. The evidence for this localization is provided by a genetic-linkage study of 91 affected sib pairs from 53 Japanese families. In this sib-pair study, D6S276, a marker lying close to the HLA complex, gives evidence for strongly significant linkage (P = .000006) to the OPLL locus. A candidate gene in the region, that for collagen 11A2, was analyzed for the presence of molecular variants in affected probands. Of 19 distinct variants identified, 4 showed strong statistical associations with OPLL (highest P = .0004). These observations of linkage and association, taken together, show that a genetic locus for OPLL lies close to the HLA region, on chromosome 6p. 相似文献
In the treatment of the soft tissue defect of the elbow, flap reconstruction is necessitated in many cases because of thinness of soft tissue at this region. In addition, reacquirement of tactile sensation is desirable because of the anatomical and specific functions of the elbow. Of three cases treated for elbow defects, one was reconstructed with a pedicled island forearm flap containing the lateral cutaneous nerve of the forearm, another was reconstructed with a venoneuro-accompanying artery fasciocutaneous flap (VNAF flap) containing the basilic vein, and the third with the VNAF flap containing the cephalic vein. The three cases demonstrated a sudden change of sensory territory 4 to 6 months after surgery, which was confirmed by touching the reconstructed region with patients'' eye-closed: from its original territory to the elbow in a “switching”-like action. Here we describe and discuss the concept of “sensory switching.” 相似文献
Optoacoustic (photoacoustic) imaging is often performed with one‐dimensional transducer arrays, in analogy to ultrasound imaging. Optoacoustic imaging using linear arrays offers ease of implementation but comes with several performance drawbacks, in particular poor elevation resolution, i.e. the resolution along the axis perpendicular to the focal plane. Herein, we introduce and investigate a bi‐directional scanning approach using linear arrays that can improve the imaging performance to quasi‐isotropic transverse resolution. We study the approach theoretically and perform numerical simulations and phantom measurements to evaluate its performance under defined conditions. Finally, we discuss the features and the limitations of the proposed method.
The poor elevation resolution in a linear scan (left image) is overcome by the proposed bi‐directional scanning approach that yields isotropic transverse resolution (right). 相似文献
Forest structural reference conditions are widely used to understand how ecosystems have been altered and guide restoration and management objectives. We used six stem‐mapped permanent plots established in the early twentieth century to provide precise structural reference conditions for ponderosa pine forests of northern Arizona prior to Euro‐American settlement. Reference conditions for these plots in 1873–1874 included the following historical attributes: tree densities of 45–127 trees/ha, mean tree diameter at breast height (dbh) of 43.8 cm with a corresponding quadratic mean diameter range of 41.5–51.3 cm, and a stand basal area of 9.2–18.0 m2/ha. The reconstructed diameter distributions (for live ponderosa pine trees with dbh ≥9.14 cm) prior to fire exclusion varied in shape but generally displayed an irregular unimodal distribution. We suggest that management objectives for the structural restoration of ponderosa pine forests of northern Arizona emphasize: (1) conservation and retention of all pre‐settlement (>130 years) trees; (2) reduction of tree densities with a restoration objective ranging between 50 and 150 trees/ha having a large‐tree component between 25 and 50% of the total trees per hectare, respectively; (3) manipulation of the diameter distribution to achieve a unimodal or irregular, uneven‐aged shape (possibly targeting a balanced, uneven‐aged shape on cinder soil types) through the use of harvest and thinning practices that mimic gap disturbances (i.e., individual tree selection system); and (4) retention of 3–11 snags and logs per hectare resulting from natural mortality. 相似文献
Abstract. A new species in the cephalaspidean family Diaphanidae, Toledonia warenella n. sp., is described from New South Wales, Australia. Three-dimensional, computer-aided reconstructions of the anatomy, based on serial histological sections, show that T. warenella n. sp. has some features in common with other diaphanids, including lack of jaws, gizzard plates, or an operculum. A gill was not detected in the mantle cavity, which is dominated by large, triangular, opposed ciliary bands and a kidney with lobed edges. The buccal mass is large with thick, muscular walls, perhaps indicative of a suctorial feeding behavior. Comparison with other diaphanid genera was hindered by lack of detailed published anatomical data, but shell and radula morphology suggests a close relationship between the new species and the polar genera Toledonia and Bogasonia (members of Toledoniinae), and for this reason, it is provisionally included in Toledonia. The systematics of Diaphanidae are addressed in the light of the anatomical data presented here. 相似文献