Alan Turing-ek morfogenesiaren inguruan egindako ikerketaren analisi matematikoa

Artikulu honetan, Alan Turing matematikariak 1952an morfogenesiaren inguruan aurkeztu zuen «The Chemical Basis of Morphogenesis» lanaren zati bat aurkeztu eta matematikoki garatuko dugu. Horretarako, beharrezkoak diren matematikako kontzeptuak eta baliabideak azalduko ditugu. Konkretuki, Alan Turingek lan horretako “Reactions and Diffusion in a Ring of Cells” (eraztun diskretuko eremua) eta “Continuous Ring of Tissue” (eraztun jarraituko eremua) ataletan gehiegi sakondu edo zehaztu gabe erabili zituen ekuazio diferentzialak, erreakzio-difusio ekuazioak, Fourier-en serieak eta funtzioen linealizazioa azalduko ditugu eta bi eremu horietan planteatutako ekuazio sistemen soluzioak bilatzeko erabiliko ditugu. Artikulu hau UPV/EHUko Idoia Marauri ikasle ohiaren Gradu Amaierako Lanean oinarrituta dago.

Intracorneal circular ring implant with femtosecond laser: Pocket versus tunnel

Purpose: To evaluate and compare visual and refractive outcomes after implantation of the intracorneal continuous ring 360° arc (ICCR) versus the intracorneal ring segment 340° arc (ICRS) using femtosecond laser for central keratoconus. Setting: Research Department, Oftalmosalud, Instituto de Ojos, Lima, Peru. Methods: Randomized study that included 40 eyes of 32 patients diagnosed with central keratoconus between November 2014 and March 2015. Twenty eyes had an implantation of ICCR (MyoRing, Dioptex GmbH, Austria) through an intrastromal pocket and 20 eyes had an implantation of ICRS (Keraring, Mediphacos, Brazil) through an intrastromal tunnel. Both procedures were performed with a femtosecond laser (LDV Z6 model, Ziemer Ophthalmic Systems AG). Visual acuity (VA), refraction, and Scheimpflug imaging analysis were performed pre- and postoperatively at 1 month and 1 year. Comparisons of means were performed using the Student’s t-test. Results: At 1 year, uncorrected VA improved 0.77 LogMAR ( p < 0.001) in the ICCR group and 0.79 LogMAR ( p = 0.01) in the ICRS group; mean sphere improvement was 5.13 Diopters (D) in the ICCR group and 6.27 D in the ICRS group ( p < 0.001 both); mean Steeper Keratometry improvement was 4.24 D in the ICCR group and 5.53 D in the ICRS group ( p < 0.001 both). In the ICCR group, mean decrease in the pachymetry at the thinnest point of the cornea was 32.16 µm ( p = 0.01), and in the ICRS group, mean increase was 4.2 µm at 1 year ( p = 0.61). Conclusion: Intracorneal continuous ring 360° arc (ICCR) and intracorneal ring segment 340° (ICRS) are effective treatments for central keratoconus. No significant differences between rings were found on visual acuity, refraction, and keratometry improvement.

Six observational pieces of evidence against corotation as the main cause for the aurora at Jupiter

&lt;p&gt;The Main Emissions are the most recognizable feature of the aurorae at Jupiter and they are responsible for roughly 1/3rd of the total emitted power. They form an ever-present and quasi-continuous ring of emission centered on the magnetic poles. The most widely accepted explanation for these auroral emissions involves a current system related to the corotation enforcement of the plasma in the Jovian magnetosphere. Models based on this theory explain many characteristics of the aurorae. However, recent observations from the NASA Juno spacecraft and the ESA/NASA Hubble Space Telescope, complemented by previous results from the NASA Galileo spacecraft, challenge this theoretical framework. In this presentation, we will review six specific sets of observations contradictory with expectations from the corotation enforcement theory:&lt;/p&gt; &lt;ol&gt; &lt;li&gt;&amp;#160;dawn/dusk asymmetries in the particle angular velocity and magnetic field bend-back,&lt;/li&gt; &lt;li&gt;fragmented and asymmetric field-aligned currents,&lt;/li&gt; &lt;li&gt;dawn/dusk brightness asymmetry,&lt;/li&gt; &lt;li&gt;global auroral brightening in response to solar wind compression,&lt;/li&gt; &lt;li&gt;auroral brightness variations as a response to magnetic loading/unloading,&lt;/li&gt; &lt;li&gt;energy distribution of the charged particles precipitating into the main auroral emissions.&lt;/li&gt; &lt;/ol&gt; &lt;p&gt;We will expose their implications for the modelling of the Jovian magnetosphere and aurorae and we will discuss promising paths forward.&amp;#160;&lt;/p&gt;

On self-injectivity of the f-ring Frm(𝓟(ℝ), L)

Let 𝓕𝓟L := Frm(𝓟(ℝ), L). We show that if L is a P-frame then 𝓕𝓟L is an ℵ0-self-injective ring. We prove that a zero-dimensional frame L is extremally disconnected if and only if 𝓕𝓟L is a self-injective ring. Finally, it is shown that 𝓕𝓟L is a Baer ring if and only if 𝓕𝓟L is a continuous ring if and only if 𝓕𝓟L is a complete ring if and only if 𝓕𝓟L is a CS-ring.