Entropy of Transcendental entire functions

We prove that all entire transcendental entire functions have infinite topological entropy.Comment: 13 page

Dynamics of transcendental H\'enon maps-II

Transcendental H\'enon maps are the natural extensions of the well investigated complex polynomial H\'enon maps to the much larger class of holomorphic automorphisms. We prove here that transcendental H\'enon maps always have non-trivial dynamical behavior, namely that they always admit both periodic and escaping orbits, and that their Julia sets are non-empty and perfect

Combined therapie of SMN-ASO and Plastin 3 overexpression rescues severe SMA in mice

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder characterized by the loss of α-motor neurons in the anterior horns of the spinal cord. This leads to atrophy of proximal symmetrical muscles and paralysis. Patients suffering from SMA in almost all cases show homozygous absence of the survival of motor neuron 1 gene (SMN1) and the severity of the disease is inversely correlated with the copy number of the main disease modifying gene survival motor neuron 2 (SMN2). Rarely, individuals with homozygous SMN1-deletion remain asymptomatic, suggesting the action of modifying gene(s). Plastin 3 (PLS3) – a F-actin binding and bundling protein - has been identified as a protective modifier showing high expression in SMN1-deleted asymptomatic siblings of SMA patients. PLS3 is highly expressed in spinal cord and axonal growth cones. PLS3 overexpression rescues the axonal outgrowth phenotype in SMA motor neuron cultures and SMA zebrafish (Oprea et al. 2008). Severely affected SMA mice carrying heterozygously a transgenic PLS3 overexpressing allele show improved motoric abilities as a consequence of improved innervation at neuromuscular junctions (NMJ), increased NMJs and muscle fibre size as well as an increase of proprioceptive input on motor neuron (MN) soma. Most importantly, PLS3 overexpression delays axon pruning and improves connectivity of the presynapse to motor endplates. Nonetheless, survival is only marginally increased by a few days, as a consequence of massive impairment of inner organs in SMA mice, which is not rescued by PLS3 overexpression (Ackermann et al. 2013). As PLS3 overexpression ameliorates some SMA hallmarks in the severe SMA mouse model, but its modifying function is likely diminished by the multi-organ impairment, we decided to study the effect of elevated PLS3 in an intermediate SMA mouse model, which would more faithfully model the condition of initially identified asymptomatic individuals. To do so, we made use of a low dose SMN-antisense oligonucleotide (ASO) that allows SMN2 splice correction (Hua et al. 2011). In this study, (1) an intermediately-affected SMA mouse model was produced by presymptomatic subcutaneous injection of low dose SMN-ASOs into the severely-affected SMA mouse model; (2) SMN-ASO treated SMA mice on congenic FVB/N background showed a much larger variability in survival than on C57BL/6N background. (3) The optimal conditions turned out to be 30 μg SMN-ASO, injected twice at P2 and P3 in C57BL/6N SMA mice. These mice showed an elongated lifespan from 14 to 28 days. (4) The suboptimal doses of SMN-ASO considerably decreased inner organ defects including intestine, lung and heart. (5) Additional overexpression of the PLS3 transgene either heterozygously or homozygously rescued survival from 28 to >250 days, weight and motoric abilities (grip strength force and tube test). These data proved that PLS3 is a protective modifier of SMA if elevated in an animal model that resembles the situation in the asymptomatic SMN1-deleted individuals. (6) In this low dose SMN-ASO injected intermediate SMA mouse model, PLS3 counteracts the defects within the neuronal circuitry by increasing NMJ size and thereby stabilizing AChR clustering at the postsynaptic site. Presynaptically, PLS3 increases the number of proprioceptive inputs at the MN soma and leads to enlarged MN soma size. (7) Even in MNs isolated from the severely affected SMA mouse model, PLS3 overexpression led to an increased length of the main axon. (8) As PLS3 knockout in yeast impairs endocytosis (Kubler and Riezman 1993), we hypothesized that disturbed endocytosis might be a key cellular mechanism underlying impaired neurotransmission and neuromuscular junction maintenance in SMA. Indeed, SMN deficit dramatically reduced endocytosis in murine embryonic fibroblasts, which was restored to control levels by overexpression of PLS3. Taken together, our findings in transgenic SMA mice demonstrate the efficacy of a combined treatment with SMN-ASO in addition to PLS3 overexpression, rather than solely increasing SMN levels. Hence, we suggest that compounds, which can restore endocytosis in combination with SMN-ASO therapy might not only improve the SMA phenotype but maybe even result in a complete rescue, and this possibility will be tested in future studies

Infinite entropy for transcendental entire functions with an omitted value

We prove that entire transcendental holomorphic functions with an omitted value have infinite entropy. A proof for general transcendental entire functions will be given in an upcoming paper.Comment: 4 page

Urbane imperiale Differenz: Verflechtungen postkolonialer und post(real) sozialistischer Konfigurationen am Beispiel von Cottbus

Der vorliegende Artikel unternimmt eine dekolonisierende Spurensuche im post(real)sozialistischen Raum Cottbus. Inspiriert durch post- und dekoloniale Städteinitiativen lokalisieren wir verschiedene Erinnerungsorte in der Stadt. Wir zeigen, wie der post(real)sozialistische urbane Raum, der aus der DDR hervorgegangen ist, auf ambivalente Weise in eine koloniale Matrix eingebunden ist. Wir rekonstruieren, wie diese spezifische Kolonialität/Modernität zur sozialen Hierarchisierung von sozialen, ökonomischen und epistemischen Beziehungen führte. Die ambivalente Positionierung der DDR, die einerseits koloniale Machtverhältnisse fortsetzte, diesen gleichzeitig entgegentrat sowie selbst von Prozessen der Abwertung betroffen war, konzeptualisieren wir als urbane imperiale Differenz. Wir argumentieren, dass die Aufarbeitung der Prozesse von Rassialisierung im (real)sozialistischen urbanen Raum wichtig ist, um gegenwärtige rechtsextreme, zuwanderungsfeindliche und rassistische Bewegungen besser verstehen zu können.This paper reflects on present and future strategies for decolonising the post(real)socialist city. Inspired by the demands of postcolonial and decolonial urban initiatives, we localise different sites of remembrance in the urban context. We show how the post(real)socialist urban space that emerged from the German Democratic Republic (GDR) ambivalently incorporated a colonial matrix. We conceptualise the ambivalent positioning of the GDR, which simultaneously continued and opposed colonial power relations, and was itself affected by processes of devaluation via urban imperial difference. We argue that it is important to reconstruct the processes of racialisation in the post(real)socialist urban space in order to better understand and oppose contemporary right wing and racist movements

Dynamics of transcendental Hénon maps-II

Transcendental Henon maps are the natural extensions of the well investigated complex polynomial Henon maps to the much larger class of holomorphic automorphisms. We prove here that transcendental Henon maps always have non-trivial dynamical behavior, namely that they always admit both periodic and escaping orbits, and that their Julia sets are non-empty and perfect

A highly prevalent filamentous algal endophyte in natural populations of the sugar kelp Saccharina latissima is not detected during cultivation in Northern Brittany

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