NUDIBRANCHS OF THE ROSS SEA, ANTARCTICA: PHYLOGENY, DIVERSITY, AND DIVERGENCE

The Southern Ocean (SO) surrounding Antarctica is extremely cold and geographically isolated. The phylogenetic affinities of only a few SO taxa have been examined in detail; in these, a high degree of endemism and radiation within the SO has been established using molecular phylogenetic methods. In order to address these Antarctic paradigms, we used Bayesian inference to construct phylogenetic trees of nudibranch molluscs based on mitochondrial cytochrome-c oxidase I (COI) and 18S ribosomal DNA. We gathered sequences from temperate (COI n=37; 18S n=31) and polar (COI n=21; 18S n=22) species and then combined them with sequences retrieved from GenBank (COI n=141; 18S n=91) in order to construct phylogenies using all available sequences. We found broad taxonomic diversity within the Nudibranchia of the Ross Sea and recovered reciprocally monophyletic clades of Anthobranchia and Cladobranchia as reported in previous molecular work. Estimates of divergence times of SO lineages from temperate taxa were calculated in three ways, with Bayesian branch lengths and using two molecular clock models implemented using BEAST v1.4.8, a program that jointly infers divergence times as well as phylogenetic relationships among taxa. The COI and 18S tree topologies both show 15 lineages (all \u3e23% divergent at COI from the nearest sequence in the tree) of Antarctic nudibranchs. Seven of these 15 SO lineages contain a single taxon whose closest relative in the phylogeny is a temperate species, while the other eight are contained in three separate clades of SO lineages. This suggests radiation within the SO over the last 25-60 Mya, coinciding with glacial disturbance of the benthos and the initiation of the Antarctic Circumpolar Current

Intentionality and Isomorphism in Aristotle

In this paper I investigate one central source of Aristotle\u27s dissatisfaction with a comprehensive analogy between aisthêsis and noêsis. I will argue that his conception of nous as organless is neither empirically motivated nor obviously misguided. On the contrary, Aristotle\u27s insistence that nous is separate and unmixed with the body is grounded in an approach to intentionality nascent in his treatment of noêsis. This approach to intentionality helps motivate the special status he awards nous

Ousia in Metaphysics VII and VIII: A Syntactic Study

The submitted paper IS the original abstract

Soul as Subject in Aristotle’s \u3cem\u3eDe Anima\u3c/em\u3e

I shall argue that we need not regard Aristotle as inconsistent as a consequence of his seeming reservations about the suitability of souls as hupokeimena; nor need we accept the suggestion of those commentators who agree with Hamlyn in holding that DA 408b11-15 provides evidence that the concept of a person or subject is generally missing from Aristotle\u27s discussion of the problems in the philosophy of mind. But it will not be possible to avail ourselves of the solutions of those commentators who seek to deny either of the first two propositions in our prima facie inconsistent triad; and by focusing on the third proposition we can come to appreciate just how concerned Aristotle is with the questions which motivate our investigations into the nature of persons and personal identity, including especially the nature of the diachronic identity of persons

In the Shadows of Dominion: Anthropocentrism and the Continuance of a Culture of Oppression

The oppression of nonhuman animals in Western culture observed in societal institutions and practices such as the factory farm, hunting, and vivisection, exhibits alarming linkages and parallels to some episodes of the oppression of human animals. This work traces the foundations of anthropocentrism in Western philosophy and connects them to the oppressions of racism, sexism, and ethnocentrism. In outlining a uniform theory of oppression detailed through the marginalization, isolation, and exploitation of human and nonhuman animals alike, parallels among the groups emerge as the fused oppression of each exhibits a commonality among them. The analysis conducted within this work highlights the development and sustainment of oppression in the West and illuminates the socio-historical tendencies apparent in the oppression of human and nonhuman animals alike

A Laser-Guided Spinal Cord Displacement Injury in Adult Mice

Mouse models are unique for studying molecular mechanisms of neurotrauma because of the availability of various genetic modified mouse lines. For spinal cord injury (SCI) research, producing an accurate injury is essential, but it is challenging because of the small size of the mouse cord and the inconsistency of injury production. The Louisville Injury System Apparatus (LISA) impactor has been shown to produce precise contusive SCI in adult rats. Here, we examined whether the LISA impactor could be used to create accurate and graded contusive SCIs in mice. Adult C57BL/6 mice received a T10 laminectomy followed by 0.2, 0.5, and 0.8 mm displacement injuries, guided by a laser, from the dorsal surface of the spinal cord using the LISA impactor. Basso Mouse Scale (BMS), grid-walking, TreadScan, and Hargreaves analyses were performed for up to 6 weeks post-injury. All mice were euthanized at the 7th week, and the spinal cords were collected for histological analysis. Our results showed that the LISA impactor produced accurate and consistent contusive SCIs corresponding to mild, moderate, and severe injuries to the cord. The degree of injury severities could be readily determined by the BMS locomotor, grid-walking, and TreadScan gait assessments. The cutaneous hyperalgesia threshold was also significantly increased as the injury severity increased. The terminal lesion area and the spared white matter of the injury epicenter were strongly correlated with the injury severities. We conclude that the LISA device, guided by a laser, can produce reliable graded contusive SCIs in mice, resulting in severity-dependent behavioral and histopathological deficits

Dissecting the Power Sources of Low-Luminosity Emission-Line Galaxy Nuclei via Comparison of HST-STIS and Ground-Based Spectra

Using a sample of ~100 nearby line-emitting galaxy nuclei, we have built the currently definitive atlas of spectroscopic measurements of H_alpha and neighboring emission lines at subarcsecond scales. We employ these data in a quantitative comparison of the nebular emission in Hubble Space Telescope (HST) and ground-based apertures, which offer an order-of-magnitude difference in contrast, and provide new statistical constraints on the degree to which Transition Objects and low-ionization nuclear emission-line regions (LINERs) are powered by an accreting black hole at <10 pc. We show that while the small-aperture observations clearly resolve the nebular emission, the aperture dependence in the line ratios is generally weak, and this can be explained by gradients in the density of the line-emitting gas: the higher densities in the more nuclear regions potentially flatten the excitation gradients, suppressing the forbidden emission. The Transition Objects show a threefold increase in the incidence of broad H_alpha emission in the high-resolution data, as well as the strongest density gradients, supporting the composite model for these systems as accreting sources surrounded by star-forming activity. The narrow-line LINERs appear to be the weaker counterparts of the Type 1 LINERs, where the low accretion rates cause the disappearance of the broad-line component. The enhanced sensitivity of the HST observations reveals a 30% increase in the incidence of accretion-powered systems at z~0. A comparison of the strength of the broad-line emission detected at different epochs implies potential broad-line variability on a decade-long timescale, with at least a factor of three in amplitude.Comment: 27 pages, 13 figures, 4 tables, accepted for publication in Ap

Idiopathic Lesions and Visual Deficits in the American Lobster (Homarus americanus) From Long Island Sound, NY

In 1999, a mass mortality of the American lobster (Homarus americanus) occurred in western Long Island Sound (WLIS). Although the etiology of this event remains unknown, bottom water temperature, hypoxia, heavy metal poisoning, and pesticides are potential causal factors. Lobsters from WLIS continue to display signs of morbidity, including lethargy and cloudy grey eyes that contain idiopathic lesions. As the effect of these lesions on lobster vision is unknown, we used electroretinography (ERG) to document changes in visual function in lobsters from WLIS, while using histology to quantify the extent of physical damage. Seventy-three percent of lobsters from WLIS showed damage to photoreceptors and optic nerve fibers, including necrosis, cellular breakdown, and hemocyte infiltration in the optic nerves, rhabdoms, and ommatidia. Animals with more than 15% of their photoreceptors exhibiting damage also displayed markedly reduced responses to 10-ms flashes of a broad-spectrum white light. Specifically, maximum voltage (Vmax) responses were significantly lower and occurred at a lower light intensity compared to responses from lobsters lacking idiopathic lesions. Nearly a decade after the 1999 mortality event, lobsters from WLIS still appear to be subjected to a stressor of unknown etiology that causes significant functional damage to the eyes