50 resultados para Gross anatomy


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Using matched employer-employee data from the German LIAB for 2001, the authors found that German works councils are in general associated with higher earnings, even after accounting for establishment- and worker heterogeneity. Works Council wage premia exceed those of collective bargaining and are higher, in fact, where both institutions are present in the workplace. The authors also found evidence indicating that works councils benefit women relative to men and appear to favor foreign, east-German, and service-sector workers as well. Separate evidence from quantile regressions suggests that the conjunction of works council presence and collective bargaining is important to the narrowing process. In smaller plants even the presence of a works council markup depends on the coexistence of the works council entity With the machinery of collective bargaining.

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Chitons are often referred to as “living fossils” in part because they are proposed as one of the earliest-diverging groups of living molluscs, but also because the gross morphology of the polyplacophoran shell has been conserved for hundreds of millions of years. As such, the analysis of evolution and radiation within polyplacophorans is of considerable interest not only for resolving the shape of pan-molluscan phylogeny but also as model organisms for the study of character evolution. This study presents a new, rigorous cladistic analysis of the morphological characters used in taxonomic descriptions for chitons in the living suborder Lepidopleurina Thiele, 1910 (the earliest-derived living group of chitons). Shell-based characters alone entirely fail to recover any recognized subdivisions within the group, which may raise serious questions about the application of fossil data (from isolated shell valves). New analysis including characters from girdle armature and gill arrangements recovers some genera within the group but also points to the lack of monophyly within the main genus Leptochiton Gray, 1847. Additional characters from molecular data and soft anatomy, used in combination, are clearly needed to resolve questions of chiton relationships. However, the data sets currently available already provide interesting insights into the analytical power of traditional morphology as well as some knowledge about the early evolution and radiation of this group.

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Modiolarca tumida (Hanley, 1843) is a member of the sub-family Crenellinae (Mytilidae). The preferred habitat of the species is the test of certain ascidians. The shell is dorsally flattened, which prevents it from cutting into the test during dorso-ventral contraction of the byssal retractors. The use of the byssus enables it to surround itself completely with host tissue. Adoption of the feeding posture involves the anterior-posterior contraction of the byssal retractors, which elevates the posterior margin above the host's surface using the anterior margin as the fulcrum against the host. Modiolarca tumida are attracted by the tunicin of the host, a process probably facilitated by the host's feeding currents. The smallest individuals are found round the oral aperture. Colonization of other parts of the host may result from surface migration as M. tumida can be highly mobile, crawling by means of the very extensible foot. It is during this process that individuals may be swept away in local currents and be forced to adopt a free-living existence.

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P>The current paper provides an overview of current knowledge on the structure and function of the eye. It describes in depth the different parts of the eye that are involved in the ocular manifestations seen in the mucopolysaccharidoses (MPS). The MPS are a group of rare inheritable lysosomal storage disorders characterized by the accumulation of glycosaminoglycans (GAGs) in cells and tissues all over the body, leading to widespread tissue and organ dysfunction. GAGs also tend to accumulate in several tissues of the eye, leading to various ocular manifestations affecting both the anterior (cornea, conjunctiva) and the posterior parts (retina, sclera, optic nerve) of the eye.