1,157 research outputs found
Endothelial dysfunction in a child with Pearson marrow-pancreas syndrome managed with Descemet stripping automated endothelial keratoplasty using a suture pull-through techniqu
A 4-year-old girl with a history of Pearson marrow-pancreas syndrome presenting with severe, progressive photophobia was found to have bilateral, diffuse corneal thickening and peripheral pigmentary retinopathy. She underwent Descemet stripping automated endothelial keratoplasty (DSAEK) surgery in both eyes using a modified suture pull-through technique. Postoperatively there was no evidence of cataract formation or graft detachment; her corneas thinned, and her photophobia improved dramatically
Four-Hundred-and-Ninety-Million-Year Record of Bacteriogenic Iron Oxide Precipitation at Sea-Floor Hydrothermal Vents
Fe oxide deposits are commonly found at hydrothermal vent sites at mid-ocean ridge and back-arc sea floor spreading centers, seamounts associated with these spreading centers, and intra-plate seamounts, and can cover extensive areas of the seafloor. These deposits can be attributed to several abiogenic processes and commonly contain micron-scale filamentous textures. Some filaments are cylindrical casts of Fe oxyhydroxides formed around bacterial cells and are thus unquestionably biogenic. The filaments have distinctive morphologies very like structures formed by neutrophilic Fe oxidizing bacteria. It is becoming increasingly apparent that Fe oxidizing bacteria have a significant role in the formation of Fe oxide deposits at marine hydrothermal vents. The presence of Fe oxide filaments in Fe oxides is thus of great potential as a biomarker for Fe oxidizing bacteria in modern and ancient marine hydrothermal vent deposits. The ancient analogues of modern deep-sea hydrothermal Fe oxide deposits are jaspers. A number of jaspers, ranging in age from the early Ordovician to late Eocene, contain abundant Fe oxide filamentous textures with a wide variety of morphologies. Some of these filaments are like structures formed by modern Fe oxidizing bacteria. Together with new data from the modern TAG site, we show that there is direct evidence for bacteriogenic Fe oxide precipitation at marine hydrothermal vent sites for at least the last 490 Ma of the Phanerozoic
Is a Trapped One-Dimensional Bose Gas a Luttinger Liquid?
The low-energy fluctuations of a trapped, interacting quasi one-dimensional
Bose gas are studied. Our considerations apply to experiments with highly
anisotropic traps. We show that under suitable experimental conditions the
system can be described as a Luttinger liquid. This implies that the
correlation function of the bosons decays algebraically preventing
Bose-Einstein condensation. At significantly lower temperatures a finite size
gap destroys the Luttinger liquid picture and Bose-Einstein condensation is
again possible.Comment: 4 pages (revtex), 1 figure (eps file
Quantum gates using electronic and nuclear spins of Yb in a magnetic field gradient
An efficient scheme is proposed to carry out gate operations on an array of
trapped Yb ions, based on a previous proposal using both electronic and
nuclear degrees of freedom in a magnetic field gradient. For this purpose we
consider the Paschen-Back regime (strong magnetic field) and employ a
high-field approximation in this treatment. We show the possibility to suppress
the unwanted coupling between the electron spins by appropriately swapping
states between electronic and nuclear spins. The feasibility of generating the
required high magnetic field is discussed
Modal Ω-Logic: Automata, Neo-Logicism, and Set-Theoretic Realism
This essay examines the philosophical significance of -logic in Zermelo-Fraenkel set theory with choice (ZFC). The duality between coalgebra and algebra permits Boolean-valued algebraic models of ZFC to be interpreted as coalgebras. The modal profile of -logical validity can then be countenanced within a coalgebraic logic, and -logical validity can be defined via deterministic automata. I argue that the philosophical significance of the foregoing is two-fold. First, because the epistemic and modal profiles of -logical validity correspond to those of second-order logical consequence, -logical validity is genuinely logical, and thus vindicates a neo-logicist conception of mathematical truth in the set-theoretic multiverse. Second, the foregoing provides a modal-computational account of the interpretation of mathematical vocabulary, adducing in favor of a realist conception of the cumulative hierarchy of sets
Recommended from our members
Iron free permanent magnet systems for charged particle beam optics
The strength and astounding simplicity of certain permanent magnet materials allow a wide variety of simple, compact configurations of high field strength and quality multipole magnets. Here we analyze the important class of iron-free permanent magnet systems for charged particle beam optics. The theory of conventional segmented multipole magnets formed from uniformly magnetized block magnets placed in regular arrays about a circular magnet aperture is reviewed. Practical multipole configurations resulting are presented that are capable of high and intermediate aperture field strengths. A new class of elliptical aperture magnets is presented within a model with continuously varying magnetization angle. Segmented versions of these magnets promise practical high field dipole and quadrupole magnets with an increased range of applicability
Do specialty registrars change their attitudes, intentions and behaviour towards reporting incidents following a patient safety course?
<p>Abstract</p> <p>Background</p> <p>Reporting incidents can contribute to safer health care, as an awareness of the weaknesses of a system could be considered as a starting point for improvements. It is believed that patient safety education for specialty registrars could improve their attitudes, intentions and behaviour towards incident reporting. The objective of this study was to examine the effect of a two-day patient safety course on the attitudes, intentions and behaviour concerning the voluntary reporting of incidents by specialty registrars.</p> <p>Methods</p> <p>A patient safety course was designed to increase specialty registrars' knowledge, attitudes and skills in order to recognize and cope with unintended events and unsafe situations at an early stage. Data were collected through an 11-item questionnaire before, immediately after and six months after the course was given.</p> <p>Results</p> <p>The response rate at all three points in time assessed was 100% (n = 33). There were significant changes in incident reporting attitudes and intentions immediately after the course, as well as during follow-up. However, no significant changes were found in incident reporting behaviour.</p> <p>Conclusions</p> <p>It is shown that patient safety education can have long-term positive effects on attitudes towards reporting incidents and the intentions of registrars. However, further efforts need to be undertaken to induce a real change in behaviour.</p
Re-cycling paradigms: cell cycle regulation in adult hippocampal neurogenesis and implications for depression
Since adult neurogenesis became a widely accepted phenomenon, much effort has been put in trying to understand the mechanisms involved in its regulation. In addition, the pathophysiology of several neuropsychiatric disorders, such as depression, has been associated with imbalances in adult hippocampal neurogenesis. These imbalances may ultimately reflect alterations at the cell cycle level, as a common mechanism through which intrinsic and extrinsic stimuli interact with the neurogenic niche properties. Thus, the comprehension of these regulatory mechanisms has become of major importance to disclose novel therapeutic targets. In this review, we first present a comprehensive view on the cell cycle components and mechanisms that were identified in the context of the homeostatic adult hippocampal neurogenic niche. Then, we focus on recent work regarding the cell cycle changes and signaling pathways that are responsible for the neurogenesis imbalances observed in neuropathological conditions, with a particular emphasis on depression
- …
