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Internal Features (internal + feature)
Selected AbstractsThe human hippocampus at 7 T,In vivo MRIHIPPOCAMPUS, Issue 1 2009Jens M. Theysohn Abstract The human hippocampus plays a central role in various neuropsychiatric disorders, such as temporal lobe epilepsy (TLE), Alzheimer's dementia, mild cognitive impairment, and schizophrenia. Its volume, morphology, inner structure, and function are of scientific and clinical interest. Magnetic resonance (MR) imaging is a widely employed tool in neuroradiological workup regarding changes in brain anatomy, (sub-) volumes, and cerebral function including the hippocampus. Gain in intrinsic MR signal provided by higher field strength scanners and concomitant improvements in spatial resolution seem highly valuable. An examination protocol permitting complete, high-resolution imaging of the human hippocampus at 7 T was implemented. Coronal proton density, T2, T2*, and fluid-attenuated inversion recovery contrasts were acquired as well as an isotropic 3D magnetization-prepared rapid acquisition gradient-echo (500 ,m isotropic voxel dimension, noninterpolated). Observance of energy deposition restrictions within acceptable scan times remained challenging in the acquisition of thin, spin-echo-based sections. At the higher resolution enabled by 7 T, demarcation of the hippocampus and some internal features including gray/white matter differentiation and depiction of the hippocampal mantle becomes much more viable when compared with 1.5 T; thus, in the future, this imaging technology might help in the diagnosis of subtle hippocampal changes. © 2008 Wiley-Liss, Inc. [source] Syntheses of Porous Self-Supporting Metal-Nanoparticle Assemblies with 3D Morphologies Inherited from Biosilica Templates (Diatom Frustules)ADVANCED MATERIALS, Issue 4 2009Zhihao Bao Porous 3D metal-nanoparticle assemblies with selectable morphologies are synthesized. Biosilica templates (diatom frustules) are first converted into silicon replicas via magnesiothermic reduction. Electroless metal deposition, followed by silicon dissolution, then yields metal-nanoparticle assemblies with the 3D template morphology (figure reveals a silver assembly; inset images reveal internal features after partial ion milling and EDX analysis). [source] Pseudotracheal tubes, larval head, and mycophagy in Sepedophilus (Coleoptera: Staphylinidae: Tachyporinae)JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 1-2 2001Leschen Newton (in: Wheeler, Q.; Blackwell, M. (eds), Fungus-Insect Relationships: Perspectives in Ecology and Evolution. New York: Columbia University Press, pp. 302–353, 1984) characterized five types of Sepedophilus larvae based on head structures and the external and internal features of the head of larvae of Sepedophilus type C are described in detail herein. A functional interpretation of structures involved with feeding is made on the basis of morphological and behavioural observations. Types C and D larvae possess tube-like epipharyngeal structures resembling dipteran labial pseudotrachea, which may play an important role in a specialized liquid-feeding process. Based on a preliminary analysis of head characters delimited by Newton (1984) it is shown that mycophagy has evolved once from a predatory ancestor, although some Sepedophilus groups may have mixed feeding strategies. The epipharyngeal tubes are demonstrated to be unique to mycophagous Sepedophilus in Coleoptera whereas the overall head structure is very similar to mycophagous larvae in the family Sphindidae. Pseudotracheen, Larvale Kopfstrukturen und Mycetophagie bei Sepedophilus (Coleoptera: Staphylinidae: Tachyporinae) Newton (in: Wheeler, Q.; Blackwell, M. (eds), Fungus-Insect Relationships: Perspectives in Ecology and Evolution. New York: Columbia University Press, pp. 302–353, 1984) charakterisierte fünf Larventypen von Sepedophilus Gistel, 1856 basierend auf abweichenden Kopfstrukturen. In der vorliegenden Arbeit werden äußere und innere Merkmale des Kopfes von Larven des Typs C detailliert beschrieben. Eine funktionelle Interpretation der am Freßvorhang beteiligten Kopfstrukturen beruht auf morphologischen Befunden und Lebendbeobachtungen. Larven der Typen C und D besitzen röhrenförmige epipharyngeale Strukturen, die an labiale Pseudotracheen von Dipteren erinnern. Sie spielen wahrscheinlich eine wichtige Rolle bei der Ernährung von verflüssigtem Substrat. Eine vorläufige Analyse von Kopfmerkmalen, die von Newton (1984) definiert wurden, ergibt ein nur einmaliges Entstehen von Mycetophagie ausgehend wahrscheinlich von räuberischen Vorfahren. Dabei kann allerdings nicht ausgeschlossen werden, daßSepedophilus -Larven auch unterschiedliche Nahrungsresourcen nutzen können. Die epipharyngealen Röhren kommen außer bei mycetophagen Sepedophilus -Arten bei keiner anderen Coleopterengruppe vor. Die übrigen Kopfstrukturen erinnern dagegen stark an mycetophage Larven der Familie Sphindidae. [source] Folk Theories of the Third KindRATIO, Issue 3 2004David Braddon-Mitchell The idea of a folk theory has played many important roles in much recent philosophy. To do the work they are designed for, they need to be both internal features of agents who possess them, and yet scrutable without the full resources of empirical cognitive science. The worry for the theorist of folk theories, is that only one of these desiderata is met in each plausible conception of a folk theory. This paper outlines a third conception that meets them both.1 [source] Smooth, undisturbed dwarf spheroidal galaxies in the Perseus cluster core: Implications for dark matter contentASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009Sj. Penny Abstract Using deep HST/ACS observations of the core of the Perseus Cluster, we identify a large population of dwarf elliptical galaxies down to MV = ,12. All these dwarfs are remarkably smooth in appearance, showing no evidence for internal features that could be the result of tidal processes or star formation induced by the cluster potential. Based on these observations and the relatively large sizes of these dwarfs, we argue that at least some must have a large dark matter component to prevent their disruption by the cluster potential. We further derive a new method to quantify the dark matter content of cluster dSphs without the use of kinematics, which are impossible to obtain at these distances. We find that mass-to-light ratios for dwarfs in the core of the Perseus Cluster are comparable to those found for Local Group dSphs, ranging between M,/L, , 1 and 120. This is evidence that dwarf spheroidals reside in dark matter subhalos that protect them from tidal processes in the cores of dense clusters (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||