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The eyes of suckermouth armoured catfish (Loricariidae, subfamily Hypostomus): pupil response, lenticular longitudinal spherical aberration and retinal topography
The dilated, round pupils of a species of suckermouth armoured catfish (Liposarcus pardalis) constrict slowly on illumination (over 35-40 min) to form crescent-shaped apertures. Ray tracing of He-Ne laser beams shows that the lenses of a related species (Pterygoplichthys etentaculus), which also has a crescent-shaped pupil, are well corrected for longitudinal spherical aberration, suggesting that the primary purpose of the irregular pupil in armoured catfish is not to correct such aberration. It is suggested that the iris operculum may serve to camouflage the pupil of these substrate-dwelling species. An examination of the catfish retina shows the photoreceptors to be exclusively single cones interspersed with elongate rods and demonstrates the presence of multiple optic nerve head papillae. Two areas of high ganglion cell density, each side of a vertically oriented falciform process, provide increased spatial resolving power along the axes examining the substrate in front of and behind the animal
INITIAL CHARACTERIZATION OF MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) CLASS IIB EXON 2 IN AN ENDANGERED RATTLESNAKE, THE EASTERN MASSASAUGA (SISTRURUS CATENATUS)
Genes of the major histocompatibility complex (MHC) play an important role in the vertebrate immune system and exhibit remarkably high levels of polymorphism, maintained by strong balancing selection. While the conservation implications of MHC variation have been explored in a variety of vertebrates, non-avian reptiles (most notably snakes) have received less attention. To address this gap and take the first steps toward more extensive population-level analyses, we cloned and sequenced MHC IIB exon 2 in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus). Based on three individuals, we found evidence of at least four putatively functional loci. These sequences exhibited relatively high levels of variation and significantly higher rates of nonsynonymous to synonymous substitutions, especially within the antigen-binding sites, indicating strong positive selection. Phylogenetic analysis revealed a pattern of trans-species polymorphism, also suggesting positive selection. These results contribute to our understanding of MHC variation in non-avian reptiles and form a basis for more studies of MHC variation in snakes of conservation concern
Topographic Organization of the Ganglion Cell Layer and Intraocular Vascularization in the Retinae of Two Reef Teleosts
The retinae of two species of teleosts, the rippled blenny Istiblennius edentulus and the blue tusk fish Choerodon albigena are examined in wholemount. The retinal topography of Nissl-stained cells within the ganglion cell layer in each species reveals a temporal (4.32 X 100 000 cells per mm2) and a nasal (3.83 X 100 000 cells per mm2) area centralis in the rippled blenny and two temporal areae centrales (8.30 X 100 000 and 8.00 X 100 000 cells per mm2) and a horizontal streak (5.00 X 100 000 cells per mm2) in the tusk fish. These areas are thought to subserve higher spatial resolution. Transcardial perfusions of indian ink reveal an extensive network of vitreal blood vessels which are supplied by the hyaloid artery and overlie the retina in each species. This rich network of vitreal vessels supplies areas of increased ganglion cell density although areas of maximum cell density are devoid of vessels to preserve the high spatial resolving power of the eye within this region. Unique blood vessel plexuses overlying the optic disc and falciform process in the tusk fish are also described. The diameter of the overlying vitreal vessels is compared to the soma sizes of cells within the ganglion cell layer
A VLBA Search for a Stimulated Recombination Line from the Accretion Region in NGC1275
The radio source 3C84, in NGC1275, has a two sided structure on parsec
scales. The northern feature, presumed to be associated with a jet moving away
from the Earth, shows strong evidence for free-free absorption. The ionized gas
responsible for that absorption would be a source of detectable stimulated
recombination line emission for a wide range of physical conditions. The VLBA
has been used to search for the H65 hydrogen recombination line. The
line is only expected to be seen against the northern feature which contains a
small fraction of the total radio flux density. This spatial discrimination
significantly aids the search for a weak line. No line was seen, with upper
limits of roughly 15% of the continuum over a velocity range of 1486 km/s with
resolutions up to 6.6 km/s. In the absence of a strong radiation field, this
would imply that the free-free absorbing gas has a wide velocity width, is
moving rapidly relative to the systemic velocity, or is concentrated in a thin,
high density structure. All of these possibilities are reasonably likely close
to an AGN. However, in the intense radiation environment of the AGN, even
considering only the radiation we actually observe passing through the
free-free absorbing gas, the non-detection is probably assured by a combination
of saturation and radiation damping.Comment: 14 pages with 4 postscript figures. Accepted for publication in the
April 2003 Astronomical Journa
Normalish amenable subgroups of the R. Thompson groups
Funding: UK Engineering and Physical Sciences Research Council (EPSRC) grant EP/R032866/1.Results in C∗ algebras, of Matte Bon and Le Boudec, and of Haagerup and Olesen, apply to the R. Thompson groups F≤T≤V. These results together show that F is non-amenable if and only if T has a simple reduced C∗-algebra. In further investigations into the structure of C∗-algebras, Breuillard, Kalantar, Kennedy, and Ozawa introduce the notion of a normalish subgroup of a group G. They show that if a group G admits no non-trivial finite normal subgroups and no normalish amenable subgroups then it has a simple reduced C∗-algebra. Our chief result concerns the R. Thompson groups F<T<V; we show that there is an elementary amenable group E<F [where here, E≅…)≀Z)≀Z)≀Z] with E normalish in V. The proof given uses a natural partial action of the group V on a regular language determined by a synchronising automaton in order to verify a certain stability condition: once again highlighting the existence of interesting intersections of the theory of V with various forms of formal language theory.PostprintPeer reviewe
The Creation of Nona: A Look at Fantasy Literature, Real Life Trauma, and World-Building
My Honors Thesis Project looks at the relationship between fantasy literature, real life trauma, and world-building. The scholarly portion of my thesis includes research that looks at the relationship through both literary and psychological perspectives. This research included looking at the works of J.R.R. Tolkien, as well as fantasy games like Dungeons & Dragons, and how they both relate or have been used to cope with trauma. The works of Cathy Caruth and Bruno Bettelheim are used to look at the relationship from a psychological perspective with the introduction of trauma theory and its ties to literature. My project also looks at how this all relates to mine and my friends’ own traumatic experience and how I have used fantasy literature to help deal with said experiences by creating a fantasy world and narrative of my own called Nona. On top of all of this, my Honors Project also includes a compendium to the fantasy world I have created called “The Traveler’s Guide to Nona”. This compendium acts as the creative project side of my Honors Thesis Project, and includes looking at some of the basic aspects of world-building, including the history of the world, its theology, races, and cultures
War Courts: Terror\u27s Distorting Effects on Federal Courts
In recent years, federal courts have tried an increasing number of suspected terrorists. In fact, since 2001, federal courts have convicted over 403 people for terrorism-related crimes. Although much has been written about the normative question of where terrorists should be tried, scant research exists about the impact these recent trials have had upon the Article III court system. The debate, rather, has focused almost exclusively upon the proper venue for these trials and the hypothetical problems and advantages that might inhere in each venue.
The war in Afghanistan, presenting a host of thorny legal issues, is now the longest war in United States history. This means that the federal courts have never endured wartime conditions for so long. As a result of this prolonged martial influence, it is clear that this war is corroding federal court jurisprudence. My research represents a first attempt at synthesizing what impact the war in general, and terror trials in particular, have had upon the federal courts. I argue that the hypothetical fear of “seepage” has become concrete. Indeed, judges already admit that the war has taken a regrettable toll on courts’ opinions.
In a trend that should alarm both tribunal proponents and detractors alike, tribunals and criminal trials are gradually growing to resemble one another. While efforts to improve the military tribunal system have enjoyed a fair level of success, long-entrenched Article III standards are deteriorating at a pace that mirrors the pace of tribunals’ improvements. A cluster of recent cases, proposed bills, and regulatory actions have narrowed the gap between Article III courts and military tribunals considerably. When viewed as a whole, these blurred lines between the military and domestic spheres draw the federal courts into disquieting congruity with the tribunal system.
I argue that these decisions and bills have altered (1) habeas jurisprudence, (2) detention policy, and (3) criminal investigatory procedure. More specifically, I contend that, as a result of a decade of federal courts accommodating the government’s campaign against terror, the criminal justice system is beginning to resemble the very military tribunals that were once the antithesis of Article III courts. In Part II, I discuss how the federal judiciary’s perspective on habeas corpus review has shifted dramatically even since the beginning of the global war on terror. In Part III, I argue that recent court decisions and administrative agency actions have created an Article III-sanctioned indefinite detention system that is almost indistinguishable from Guantánamo Bay. In Part IV, I observe that courts have relaxed their threshold evidentiary requirements to a point that is strikingly similar to those of military tribunals. In short, courts are becoming military commissions that convict
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