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Refraktives und visuelles Ergebnis nach Neuausrichtung von rotierten torischen Intraokularlinsen
(2023)
Hintergrund und Ziel der Studie
Das Ziel der Studie ist die Beurteilung des refraktiven und visuellen Ergebnisses von Patienten mit fehlausgerichteten torischen IOLs nach operativer Neuausrichtung, mit und ohne Rückberechnung der torischen Achse nach Implantation der IOL.
Methoden
Dies ist eine retrospektive Analyse von 39 Patienten, die sich von August 2013 bis Dezember 2019 an der Klinik für Augenheilkunde der Goethe-Universität Frankfurt am Main einer zweiten Operation zur Neuausrichtung einer fehlausgerichteten torischen IOL unterzogen haben. Die zweite Operaton zur Korrektur der Achsenlage wurde auf zwei Weisen durchgeführt: In der ersten Gruppe wurde auf die primär berechnete Achse rotiert und in der zweiten Gruppe wurde die Rotation auf eine neu berechnete Achse mit dem Rückrechner von astigmatisfix.com vorgenommen.
Ergebnisse
In dieser retrospektiven Studie wurden 39 Augen von 39 Patienten eingeschlossen. Die Ergebnisse nach der ersten Operation (die Linsenoperation) zeigte eine Besserung der (BCVA) von 0,28 ± 0,22 logMAR (20/40) auf 0,15 ± 0,14 logMAR (20/32). Nach der Linsenoperation zeigten die torischen IOLs durchschnittlich eine postoperative Fehlstellung von 25,69° ± 26,06°. Verglichen vor und nach der Rotation der torischen IOL blieb der BCVA unverändert bei 0,14 ± 0,14 logMAR (20/32), während sich der UDVA signifikant von 0,39 ± 0,29 logMAR (20/50) auf 0,27 ± 0,18 logMAR (20/40) verbesserte. Das refraktive Ergebnis zeigte eine Reduktion sowohl in der Restsphäre sowie in dem Zylinder. Die Ergebnisse der Gruppenanalyse demonstrierte für die erste Gruppe (Neuausrichtung auf die präoperativ berechnete Achse) eine postoperative UDVA 0,24 ± 0,16 logMAR mit einem Zylinder von 0,90 ± 0,90 D. In der zweiten Gruppe (Ausrichtung auf eine zurückberechnete Achse) betrug die UDVA 0,32 ± 0,20 logMAR mit einem Zylinder von 0,76 ± 0,72 D. Die IOLs mit hoher Zylinderstärke (≥ 2 D) zeigten bei der Rückberechnung eine stärkere Abnahme des Restzylinders als IOL mit niedriger Zylinderstärke (< 2 D) (27 % vs. 9 %). Der mittlere sphärische Äquivalent-Vorhersagefehler der Rückberechnung betrug 0,54 ± 0,55 D.
Schlussfolgerung
Die Neuausrichtung von fehlausgerichteten torischen IOLs verbessert die Sehschärfe und reduziert verbleibende Brechungsfehler. Insbesondere bei IOL mit hoher Zylinderstärke kann ein besseres refraktives Ergebnis erzielt werden, wenn vor der Neuausrichtung eine Rückberechnung durchgeführt wird.
Epigenetic neural glioblastoma enhances synaptic integration and predicts therapeutic vulnerability
(2023)
Neural-tumor interactions drive glioma growth as evidenced in preclinical models, but clinical validation is nascent. We present an epigenetically defined neural signature of glioblastoma that independently affects patients survival. We use reference signatures of neural cells to deconvolve tumor DNA and classify samples into low- or high-neural tumors. High-neural glioblastomas exhibit hypomethylated CpG sites and upregulation of genes associated with synaptic integration. Single-cell transcriptomic analysis reveals high abundance of stem cell-like malignant cells classified as oligodendrocyte precursor and neural precursor cell-like in high-neural glioblastoma. High-neural glioblastoma cells engender neuron-to-glioma synapse formation in vitro and in vivo and show an unfavorable survival after xenografting. In patients, a high-neural signature associates with decreased survival as well as increased functional connectivity and can be detected via DNA analytes and brain-derived neurotrophic factor in plasma. Our study presents an epigenetically defined malignant neural signature in high-grade gliomas that is prognostically relevant.
Elliptic flow of heavy-flavor decay electrons in Au+Au collisions at √sNN = 27 and 54.4 GeV at RHIC
(2023)
We report on new measurements of elliptic flow (v2) of electrons from heavy-flavor hadron decays at mid-rapidity (|y|<0.8) in Au+Au collisions at sNN−−−√ = 27 and 54.4\,GeV from the STAR experiment. Heavy-flavor decay electrons (eHF) in Au+Au collisions at sNN−−−√ = 54.4\,GeV exhibit a non-zero v2 in the transverse momentum (pT) region of pT< 2\,GeV/c with the magnitude comparable to that at sNN−−−√=200 \,GeV. The measured eHF v2 at 54.4\,GeV is also consistent with the expectation of their parent charm hadron v2 following number-of-constituent-quark scaling as other light and strange flavor hadrons at this energy. These suggest that charm quarks gain significant collectivity through the evolution of the QCD medium and may reach local thermal equilibrium in Au+Au collisions at sNN−−−√=54.4\,GeV. The measured eHF v2 in Au+Au collisions at sNN−−−√= 27\,GeV is consistent with zero within large uncertainties. The energy dependence of v2 for different flavor particles (π,ϕ,D0/eHF) shows an indication of quark mass hierarchy in reaching thermalization in high-energy nuclear collisions.
The elliptic (v2) and triangular (v3) azimuthal anisotropy coefficients in central 3He+Au, d+Au, and p+Au collisions at sNN−−−√ = 200 GeV are measured as a function of transverse momentum (pT) at mid-rapidity (|η|<0.9), via the azimuthal angular correlation between two particles both at |η|<0.9. While the v2(pT) values depend on the colliding systems, the v3(pT) values are system-independent within the uncertainties, suggesting an influence on eccentricity from sub-nucleonic fluctuations in these small-sized systems. These results also provide stringent constraints for the hydrodynamic modeling of these systems.
Uniform sampling from the set G(d) of graphs with a given degree-sequence d=(d1,…,dn)∈Nn is a classical problem in the study of random graphs. We consider an analogue for temporal graphs in which the edges are labeled with integer timestamps. The input to this generation problem is a tuple D=(d,T)∈Nn×N>0 and the task is to output a uniform random sample from the set G(D) of temporal graphs with degree-sequence d and timestamps in the interval [1,T]. By allowing repeated edges with distinct timestamps, G(D) can be non-empty even if G(d) is, and as a consequence, existing algorithms are difficult to apply.
We describe an algorithm for this generation problem which runs in expected time O(M) if Δ2+ϵ=O(M) for some constant ϵ>0 and T−Δ=Ω(T) where M=∑idi and Δ=maxidi. Our algorithm applies the switching method of McKay and Wormald [1] to temporal graphs: we first generate a random temporal multigraph and then remove self-loops and duplicated edges with switching operations which rewire the edges in a degree-preserving manner.
Uniform sampling from the set G(d) of graphs with a given degree-sequence d=(d1,…,dn)∈Nn is a classical problem in the study of random graphs. We consider an analogue for temporal graphs in which the edges are labeled with integer timestamps. The input to this generation problem is a tuple D=(d,T)∈Nn×N>0 and the task is to output a uniform random sample from the set G(D) of temporal graphs with degree-sequence d and timestamps in the interval [1,T]. By allowing repeated edges with distinct timestamps, G(D) can be non-empty even if G(d) is, and as a consequence, existing algorithms are difficult to apply.
We describe an algorithm for this generation problem which runs in expected time O(M) if Δ2+ϵ=O(M) for some constant ϵ>0 and T−Δ=Ω(T) where M=∑idi and Δ=maxidi. Our algorithm applies the switching method of McKay and Wormald [1] to temporal graphs: we first generate a random temporal multigraph and then remove self-loops and duplicated edges with switching operations which rewire the edges in a degree-preserving manner.
Predator-prey interactions are vital for organismal survival. They shape anti-predator mechanisms and often depend on sensory abilities. Tadpoles use chemical cues, such as injury cues (alarm cues), to assess predation risks and modify their life-history, morphology, and behaviours accordingly. However, the prevalence of chemically mediated anti-predator responses in species with distinct ecological niches (e.g. within phytotelmata) remains unknown, hindering our understanding of the ecological significance and evolution of alarm substances. Therefore, our study aimed to investigate chemically mediated anti-predator responses in tadpoles of two Neotropical poison dart frogs, Ranitomeya sirensis and Epipedobates anthonyi (and compare their responses to two Palearctic model organisms, Rana temporaria and Bufo bufo, which are known to utilise alarm substances). Through behavioural bioassays, we exposed predator-naïve tadpoles to extracts of each species (i.e. con- and heterospecific cues), including water as a control (i.e. five treatments per species). We assessed changes in their activity before and after stimulus introduction. Our results show that E. anthonyi did not respond to any of the stimuli, whereas R. sirensis displayed increased activity levels exclusively in response to conspecific cues, but not to heterospecific cues. With this, our findings suggest a specialized recognition system in R. sirensis, potentially directed at conspecific competitors but likely unrelated to anti-predator mechanisms. In contrast, E. anthonyi may be insensitive to injury cues or utilize alternative sensory modalities to respond to acute predation events. This study sheds light on the chemical alarm response system of Neotropical poison dart frog tadpoles, providing foundational understanding of how dendrobatids react to injury cues. It prompts questions about the ecological significance and evolutionary implications of chemical communication in species facing extreme resource limitation during development and underscores the importance of comparative research for understanding chemical communication in diverse aquatic ecosystems.
Geometry is part of the core of mathematics. It has been relevant ever since people have interacted with nature and its phenomena. Geometry’s relevance to the teaching and learning of mathematics can be emphasized, too. Nevertheless, a current potential shift in the topics of mathematics education to the detriment of geometry might be emerging. That is, other topics related to mathematics are seeming to grow in importance in comparison to geometry. Despite this, or perhaps because of it, geometry is an important component of current research in mathematics education. In the literature review, we elaborate relevant foci on the basis of current conference proceedings. By means of about 50 journal articles, five main topics are elaborated in more detail: geometric thinking and practices, geometric contents and topics, teacher education in geometry, argumentation and proof in geometry, as well as the use of digital tools for the teaching and learning of geometry. Conclusions and limitations for current and future research on geometry are formulated at the end of the article. In particular, the transfer to the practices of geometric teaching is explored on the basis of the elaborated research findings in order to combine both aspects of the teaching and learning of geometry.
Highlights
• We propose a framework to address landscape effects on ecosystem services.
• We expect ecosystem service flows to be modulated by the amount and configuration of supply and demand areas.
• We stress the role of neutral areas in facilitating or hindering ecosystem service flows.
• Supply/demand ratios, spatial overlap, and ES characteristics need to be accounted for when assessing flows.
• We propose a research agenda with challenges to couple the effects of landscape configuration on ES flow.
Abstract
Despite advances in understanding the effects of landscape structure on ecosystem services (ES), many challenges related to these complex spatial interactions remain. In particular, the integration of landscape effects on different components of the service provision chain (supply, demand, and flow) remains poorly understood and conceptualized. Here we propose a theoretical framework to further explore how the spatial flow of ES can vary according to landscape structure (i.e. composition and configuration) emphasizing the role played by the configuration of supply, demand, and neutral areas, as well as individual characteristics of ES (e.g., service rivalry). For this, we expand the discussion on how landscape changes can affect ES flows and propose a theoretical representation of ES flows variation led by different supply-demand ratios. Additionally, we expand this discussion by integrating the potential effects of neutral areas in the landscape as well as of supply/demand spatial overlap. This novel approach links the spatial arrangement (e.g. fragmentation, network complexity, matrix resistance) usually captured by landscape metrics, and ratios of ES supply and demand areas to potential effects on spatial flows of ES. We discuss the application of this model using widely studied ES, such as pollination, pest control by natural enemies, and microclimate regulation. Finally, we propose a research agenda to connect the presented ideas with other prominent research topics that must be further developed to support landscape management targeting ES provision. The prominence of ES science calls for contributions such as this to give the scientific community the opportunity to reflect on the underlying mechanisms of ES and avoid oversimplified spatial assessments.