Sacoglossa belongs to the Subclass of Opithsobrabchia (Class: Gastropoda). There are about 300 species in the world. The radula of Sacoglossa is composed of ascending limb, descending limb, and a ascus sac to store used teeth. This ascus sac is a unique character of sacoglossans in mollusus. In this study, I compared the morphology, and the composition of elements in sacoglossan radulae. A total of 16 species in 5 families, including 12 new records, has been observed. Their teeth morphology was triangular or blade-like. The radula sac is surrounded by a layer of epithelium cells and the arrangement of the teeth in the sac was linear, dense or fraction. Positive correlations between body length and the number of ascending radular teeth, descending radular teeth, teeth in ascus sac or the total number of teeth were found except for Volvatella vigourouxi (Family: Volvatellidae). The elemental compositions in various radula parts were examined by energy dispersive spectrometer. I found that sacoglossan teeth were composited by Fe, Na, Mg, Si, P, S and Ca, and no significant difference among parts but significantly different among species. In contrast, elemental compositions of sacoglossans were significantly different from Tambja sp. (Order: Nudibranchia), Aplysia parvula (Order: Anaspidea) and Cellana toreuma (Order: Archaeogastropoda). In the meantime, sacoglossans and Tambja sp. were closer than others. Additionally, hollow or broken teeth were found in some sacogloosan ascus indicates that tooth reabsorption may present. However, further study is necessary to elucidate the reabsorption mechanism.

Thesis (Ph. D.)--University of Chicago, Dept. of Organismal Biology and Anatomy, June 2001. / Includes bibliographical references. Also available on the Internet.

Includes bibliographical references (p. 118-122).

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Ecology and Evolution." Includes bibliographical references (p. 95-107).

Thesis (PH. P.)--University of Chicago, 1908. / "Reprinted from the Botanical gazette, vol. LIII, no. 3, March 1912." "Literature cited": p. 202.

ABSTRACT Infertility is a medical condition that affects approximately 16 % of Swedish couples in childbearing age and is a condition found in both men and women. When a couple has been trying to conceive for more than 12 months without success they need to see a health care provider. Infertility can be treated with medicine, insemination or assisted reproductive technology such as in-vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI). The aim of this study was to validate a morphokinetic selection model, KIDScore™ D3 Basic, against morphological selection model that is currently in use at the Fertility unit at University hospital in Orebro. A total of 782 embryos with known implantation data were assessed both y use of KIDScore™ D basic and the morphological selection model. The results from the study showed that KIDScore™ D3 Basic better discriminates between implanting and non-implanting embryos. Another strong finding in this study was the notion that presence of multinucleation at the two cell stage decreased chance of implantation significantly. The majority of implanting embryos belonged to the best morphokinetic class, whereas for morphology the majority of implanting embryos belonged to the second best class. The combination it of morphology and morphokinetic is to recommend as clinical use as it provided the best selection tool.

Parasite population dynamics and the evolution of life history characteristics are strongly correlated with the processes of host infection, survival within a host and reproduction, with each process posing a challenge to the parasitic lifestyle. Macroparasites living in marine environments have evolved extreme changes in physiology, morphology and life history traits to overcome these challenges. This study focused on the infective and reproductive stage of the parasitic isopod, Cymothoa excisa, a common parasite on Atlantic croaker, (Micropogonias undulatus), along the Texas coast. A two year survey identified infection rates and the relationship between fish density and size and parasite load, size and fecundity. Isopod morphology was quantified for each life stage, identifying shape transitions through ontogeny and sex change. Sex change in C. excisa was found to be driven by the absence of conspecific parasites within a host, where sex change only occurred in the first individual to arrive. To understand the infective stage of C. excisa parasite energetics and host detection mechanisms were tested. Parasites with free-living life stages have a narrow window to infect a host and have evolved a number of mechanisms to detect and locate a host. I used a series of energetic experiments to determine an infection window for free-swimming larvae (mancae) and behavioral response experiments testing both visual and chemical cues associated with host detection. Mancae were found to have a narrow infection window, where mancae began searching for a host as soon as they are born, but quickly switch to an ambush strategy to conserve energy. Mancae were also found to be responsive to both visual and chemical cues from its common fish host, as well as a non-host fish, indicating that chemical cues are used in host detection, but chemical specificity is not a mechanism that C. excisa uses to find its common host. The results from this study have implications to parasitic species and their hosts, as well as to other areas of study, including population and ecosystem dynamics. / text

This report presents a classification of the verbs of Zenzontepec Chatino (ZEN) based on which allomorphs of the aspect markers they select. The selection of aspect markers is determined by the semantics of the verbs, derivational morphology, and phonological factors. Before now, aspect marking in Chatino has proven opaque because previously documented varieities have undergone considerable phonological and morphological reduction, wiping out some of the earlier patterns. ZEN, on the other hand, is conservative in this respect. There are three verb classes, each with a few sub-classes, and they line up well with the verb classes that Kaufman (1993) has proposed for Proto-Zapotec. In addition to describing the verb class system for ZEN in synchronic terms, this study provides insight into the Proto-Zapotecan verb class system and documents in Chatino several derivational morphemes reconstructed for Proto-Zapotec, proving that they are of Proto-Zapotecan vintage. / text

A knowledge of morphology can be useful for many natural language processing systems. Thus, much effort has been expended in developing accurate computational tools for morphology that lemmatize, segment and generate new forms. The most powerful and accurate of these have been manually encoded, such endeavors being without exception expensive and time-consuming. There have been consequently many attempts to reduce this cost in the development of morphological systems through the development of unsupervised or minimally supervised algorithms and learning methods for acquisition of morphology. These efforts have yet to produce a tool that approaches the performance of manually encoded systems. Here, I present a strategy for dealing with morphological clustering and segmentation in a minimally supervised manner but one that will be more linguistically informed than previous unsupervised approaches. That is, this study will attempt to induce clusters of words from an unannotated text that are inflectional variants of each other. Then a set of inflectional suffixes by part-of-speech will be induced from these clusters. This level of detail is made possible by a method known as alignment and transfer (AT), among other names, an approach that uses aligned bitexts to transfer linguistic resources developed for one language–the source language–to another language–the target. This approach has a further advantage in that it allows a reduction in the amount of training data without a significant degradation in performance making it useful in applications targeted at data collected from endangered languages. In the current study, however, I use English as the source and German as the target for ease of evaluation and for certain typlogical properties of German. The two main tasks, that of clustering and segmentation, are approached as sequential tasks with the clustering informing the segmentation to allow for greater accuracy in morphological analysis. While the performance of these methods does not exceed the current roster of unsupervised or minimally supervised approaches to morphology acquisition, it attempts to integrate more learning methods than previous studies. Furthermore, it attempts to learn inflectional morphology as opposed to derivational morphology, which is a crucial distinction in linguistics. / text

A focus on river and stream morphology with a specific emphasis on how urbanization and human impacts affect river channels. In the study of rivers, specifically looking at how the channel geometry changes with time, there are five main physical factors described that affect the channel morphology: (1) bank and bar stability; (2) sediment size distribution; (3) sediment supply; (4) flow variability; and (5) downstream slope, width and height. Understanding how these five factors affect channel form is vital in constructing realistic and accurate models of rivers and how they change over time. It is also important to understand some of the limitations of the combined modeling of all these factors together for a general stream. Research studies are presented in order to further understand what knowledge has been acquired, and what areas are lacking in adequate understanding. Examples of cases where urbanization and land use change have a large impact and almost no impact are examined. It is important to understand what the limiting factors are in such cases, and whether it is possible to mitigate the effects or urbanization by any means other than natural channel phenomenon. A two-dimensional hydrodynamic and sediment transport model is thoroughly described. The model is evaluated and verified, and potential problems and limitations are then discussed. Then a one-dimensional sediment transport and bed variation model is examined and tested using parameter controlled cases. Urbanization increase near rivers and streams reduces the time frame over which certain natural events would have occurred in those channels. The affects of urbanization include but are not limited to changes in streamflow, sediment transport and deposition, channel bank stability, and increased channel widening. The magnitude of these affects will increase over time if careful steps are not taken to minimize the human influence within channels. / text