Motor neuron differentiation in the developing and the regenerating adult spinal cord of zebrafish Danio rerio (Hamilton, 1822).

Zebrafish, in contrast to mammals, are capable of functional spinal cord regeneration. Spinal motor neurons are major targets for axons regenerating from the brainstem. Using immunohistochemical markers and transgenic reporter fish for motor neuron markers (H89, islet -1), this study demonstrates that large differentiated motor neurons are transiently lost after a spinal lesion, suggesting that these cells undergo cell death after a lesion and may be replaced by proliferation. Indeed, a massive and transient increase in the number of small, undifferentiated motor neurons, which were labelled by the proliferation marker bromodeoxyuridine, was observed. Proliferation and lineage tracing studies indicated significant proliferation only at the spinal ventricle and that a subset of olig2 expressing ependymo -radial glial cells are the likely motor neuron progenitor /stem cells in the lesioned spinal cord. A spinal lesion increased expression of sonic hedgehog (shh), an embryonic differentiation signal for motor neurons. Blocking this signal with an antagonist reduced progenitor cell proliferation and motor neuron differentiation. This suggests that shh is an important signal for motor neuron differentiation during adult motor neuron regeneration.To learn more about axonal differentiation of motor neurons, the role of the cell recognition molecule plexinA3 was investigated during the outgrowth of embryonic primary motor axons. The molecule is selectively expressed in primary motor neurons. Knockdown of expression led to ectopic exiting from the spinal cord and excessive branching of motor axons. Over -expression of full length plexinA3 rescued this effect, indicating specificity of experimental manipulations. Thus, plexinA3 expression is crucial for motor axon pathfinding during development. Overall, this study demonstrates that adult zebrafish are capable of motor neuron regeneration from endogenous progenitor /stem cells and that shh is an important regulator of motor neuron regeneration. PlexinA3 is crucial for motor axon differentiation in embryonic zebrafish. This study establishes adult spinal cord lesion as a model system for motor neuron regeneration, which may ultimately help to find ways to promote motor neuron regeneration also in human conditions, such as spinal cord injury or motor neuron disease

Neue Regionen durch Kooperation in der polyzentrischen "Metropole Ruhr"

Der vorliegende Beitrag setzt sich mit neuen Formen der Regionalisierung im Rahmen interkommunaler Kooperationen in der Metropole Ruhr auseinander. Diese strategisch ausgerichteten Interaktionen stehen häufig in einem Spannungsverhältnis sowohl mit formell verfassten als auch mit anderen informellen Regionen. Die sich hieraus ergebende Überlagerung der Handlungsräume, die Flexibilität der Abgrenzungen und die unterschiedlichen Dichten der Interaktionsbeziehungen zwischen den Akteuren zählen zu den Spezifika dieser neuen Regionalisierungsvarianten von unten. Anknüpfend an einige theoretisch-konzeptionelle Überlegungen werden beispielhaft Prozesse des „Region Building“ in der polyzentrischen Metropole Ruhr betrachtet, wobei insbesondere Fragen nach der Pfadabhängigkeit regionaler Kooperationsprozesse, dem Aufbau institutioneller Kapazitäten und den Handlungsmotiven der Akteure im Mittelpunkt stehen. Der Beitrag schließt mit einer kritischen Reflexion der fachtheoretischen Debatte um Regional Governance.This paper discusses new forms of regionalisation within the framework of intermunicipal co-operation within the Ruhr Metropolis. Frequently there is a distinct tension between these cases of strategic interaction, on the one hand, and both formally constituted and more informally perceived regions. Overlapping jurisdictions, flexible boundaries and divergences in the density of patterns of interaction among the various actors are some of the features which typify these new, bottom-up variants of regionalisation. In a theory-led approach, the authors provide illustration by examining processes of “region building” in the polycentric Ruhr Metropolis; the main focus here is on issues relating to the path-dependency of processes of regional co-operation, the creation of institutional capacity and the motivation of the various actors involved. The paper closes with a critical reflection on the on-going debate within planning theory on “regional governance”

Planungskultur

Planungskulturelle Ansätze tragen zu einem vertieften Verständnis der Planungspraxis bei, indem sie die Denkmuster und Handlungsroutinen von Planenden und Planungsinstitutionen auf Basis (gesellschaftlich) typischer Orientierungen und zugehöriger Werthaltungen identifizieren

Die REGIONALEN als Instrument regionalisierter Strukturpolitik in Nordrhein-Westfalen - das Beispiel der REGIONALE 2010 Köln/Bonn

Der Beitrag beschäftigt sich mit den REGIONALEN in Nordrhein-Westfalen als Instrument regionalisierter Strukturpolitik. Im Rahmen der mittlerweile sechsten REGIONALEN präsentiert die Region Köln/Bonn im Jahr 2010 die Ergebnisse eines mehrjährigen Kooperationsprozesses. Die „Zukunftssicherung“ wurde zum zentralen Thema des zeitlich befristeten, projektorientierten Ansatzes gemacht. Bei den beteiligten Akteuren und der Öffentlichkeit konnte sich die REGIONALE 2010 als positives Schlüsselsymbol etablieren. Als Erfolgsfaktoren lassen sich die Organisations- und Kooperationsstrukturen, die Förderung und gebaute bzw. erlebbare Erfolge sowie deren Vermarktbarkeit identifizieren. Mit hohem Aufwand gelingt es, in der heterogenen Region ein gemeinsames Agieren vieler zentraler Akteure zu erzeugen, was sich auch in der frühzeitigen Festlegung auf eine Nachfolgestruktur manifestiert. Die Chancen stehen gut, dass die im Rahmen der „Institutionalisierung auf Zeit“ geschaffenen Grundlagen sowohl auf der Projekt- als auch auf der programmatischen und organisatorischen Ebene über das Präsentationsjahr hinaus tragen.This paper is concerned with the programme of REGIONALE events organised in North Rhine-Westphalia as an instrument of regionalised structure policy. Within the framework of what is now the sixth REGIONALE, in 2010 the Cologne/Bonn region will present the results of a process of co-operation which stretches back over many years. The central theme chosen for this project-based and time-limited programme is “Safeguarding the Future”. REGIONALE 2010 has been able to establish itself both among the actors involved and among the general public as a positive and emblematic symbol. The factors behind its success can be identified as the organisational and co-operative structures it employs, the funding it receives, as well as the physical and tangible successes it presents, and the manner in which they are marketed. With a great deal of effort, and at considerable expense, the REGIONALE is able to generate joint action within this heterogeneous region on the part of a host of key actors; this is manifested not least in the success in deciding on a follow-up structure at a relatively early point in the process. There is every likelihood that the foundation which was established as part of what is termed “long-term institutionalisation” – both at the project level and at the programme and organisational level – will remain in place after the presentation year comes to an end

A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope to study the gamma-ray emission towards 13 globular clusters. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices $(0.7 < \Gamma <1.4)$ and clear evidence for an exponential cut-off in the range 1.0-2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices $(1.0 < \Gamma < 1.7)$, however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600-4700 MSPs in Galactic globular clusters, commensurate with previous estimates. The observation of high-energy gamma-ray emission from a globular cluster thus provides a reliable independent method to assess their millisecond pulsar populations that can be used to make constraints on the original neutron star X-ray binary population, essential for understanding the importance of binary systems in slowing the inevitable core collapse of globular clusters.Comment: Accepted for publication in A&A. Corresponding authors: J. Kn\"odlseder, N. Webb, B. Pancraz

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

Generation and processing of complex photon states with quantum frequency combs

The development of technologies for quantum information (QI) science demands the realization. and precise control of complex (multipartite and high dimensional) entangled systems on practical and scalable platforms. Quantum frequency combs (QFCs) represent a powerful tool towards this goal. They enable the generation of complex photon states within a single spatial mode as well as their manipulation using standard fiber-based telecommunication components. Here, we review recent progress in the development of QFCs, with a focus on results that highlight their importance for the realization of complex quantum states. In particular, we outline recent work on the use of integrated QFCs for the generation of high-dimensional multipartite optical cluster states - lying at the basis of measurement-based quantum computation. These results confirm that the QFC approach can provide a stable, practical, low-cost, and established platform for the development of quantum technologies, paving the way towards the advancement of QI science for out-of-the-lab applications, ranging from practical quantum computing to more secure communications

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Strategic green infrastructure planning in Germany and the UK: a transnational evaluation of the evolution of urban greening policy and practice

The evolution of Green Infrastructure (GI) planning has varied dramatically between nations. Although a grounded set of principles are recognized globally, there is increasing variance in how these are implemented at a national and sub-national level. To investigate this the following paper presents an evaluation of how green infrastructure has been planned for in England and Germany illustrating how national policy structures facilitate variance in application. Adopting an evaluative framework linked to the identification of GI, its development and monitoring/ feedback the paper questions the impacts on delivery of intersecting factors including terminology, spatial distribution and functionality on effective GI investment. This process reviews how changing policy structures have influenced the framing of green infrastructure policy, and subsequent impact this has on the delivery of green infrastructure projects

Fully Immunocompetent CD8+ T Lymphocytes Are Present in Autologous Haematopoietic Stem Cell Transplantation Recipients Despite an Ineffectual T-Helper Response

BACKGROUND: Reduced CD4 T lymphocytes counts can be observed in HIV infection and in patients undergoing autologous haematopoietic stem cell transplantation (ASCT). Nevertheless, whereas opportunistic infections (OI) are frequent in HIV-infected individuals with low cell counts, OI are uncommon in ASCT patients. METHODOLOGY/PRINCIPAL FINDINGS: To verify whether this observation could be secondary to intrinsic HIV-correlated T cell defects, we performed in-depth immunologic analyses in 10 patients with comparable CD4 counts in whom lymphopenia was secondary either to HIV-infection or ASCT-associated immunosuppressive therapy and compared them to age-matched healthy subjects. Results showed the presence of profound alterations in CD4+ T lymphocytes in both groups of patients with respect to healthy controls. Thus, a low percentage of CCR7+ CD4+ T cells and a compensative expansion of CD45RA-CCR7- CD4+ T cells, a reduced IL-2/IFN-gamma cytokine production and impaired recall antigens-specific proliferative responses were detected both in ASCT and HIV patients. In stark contrast, profound differences were detected in CD8+ T-cells between the two groups of patients. Thus, mature CD8+ T cell prevailed in ASCT patients in whom significantly lower CD45RA-CCR7- cells, higher CD45RA+CCR7- CD8+ cells, and an expansion of CCR7+CD8+ cells was detected; this resulted in higher IFN-gamma +/TNFalpha production and granzyme CD8+ expression. The presence of strong CD8 T cells mediated immune responses justifies the more favorable clinical outcome of ASCT compared to HIV patients. CONCLUSION/SIGNIFICANCE: These results indicate that CD8 T cells maturation and functions can be observed even in the face of a profound impairment of CD4+ T lymphocytes in ASCT but not in HIV patients. Primary HIV-associated CD8 defects or an imprinting by an intact CD4 T cell system in ASCT could justify these results