Surfatron and stochastic acceleration of electrons in astrophysical plasmas

Electron acceleration by large amplitude electrostatic waves in astrophysical plasmas is studied using particle-in-cell (PIC) simulations. The waves are excited initially at the electron plasma frequency $\omega_{\rm pe}$ by a Buneman instability driven by ion beams: the parameters of the ion beams are appropriate for high Mach number astrophysical shocks, such as those associated with supernova remnants (SNRs). If $\omega_{\rm pe}$ is much higher than the electron cyclotron frequency $\Omega_{\rm e}$, the linear phase of the instability does not depend on the magnitude of the magnetic field. However, the subsequent time evolution of particles and waves depends on both $\omega_{\rm pe}/\Omega_{\rm e}$ and the size of the simulation box $L$. If $L$ is equal to one wavelength, $\lambda_0$, of the Buneman-unstable mode, electrons trapped by the waves undergo acceleration via the surfatron mechanism across the wave front. This occurs most efficiently when $\omega_{\rm pe}/\Omega_{\rm e} \simeq 100$: in this case electrons are accelerated to speeds of up $c/2$ where $c$ is the speed of light. In a simulation with $L=4\lambda_0$ and $\omega_{\rm pe}/\Omega_{\rm e} = 100$, it is found that sideband instabilities give rise to a broad spectrum of wavenumbers, with a power law tail. Some stochastic electron acceleration is observed in this case, but not the surfatron process. Direct integration of the electron equations of motion, using parameters approximating to those of the wave modes observed in the simulations, suggests that the surfatron is compatible with the presence of a broad wave spectrum if $\omega_{\rm pe}/\Omega_{\rm e}> 100$. It is concluded that a combination of stochastic and surfatron acceleration could provide an efficient generator of mildly relativistic electrons at SNR shocks

Die Lebenssituation von älteren Menschen mit lebenslanger Behinderung in Nordrhein-Westfalen

Dieser Bericht widmet sich der Lebenssituation von alten Menschen mit einer lebenslangen Behinderung in Nordrhein-Westfalen. Von einer lebenslangen Behinderung sprechen wir, wenn sie bis zum 35. Lebensjahr erworben wird, weil danach die Berufsfindung, der Einstieg ins Erwerbsleben und die Familiengründung – Ereignisse, die sich stark auf Teilhabemöglichkeiten im Alter auswirken – weitgehend abgeschlossen sind. Wie groß ist der Personenkreis und was lässt sich über seine zahlenmäßige Entwicklung sagen? In NRW leben zum 31.12.2011 gemäß eigener Berechnung 294.961 Menschen mit lebenslanger Behinderung, davon sind 69.613 über 60 Jahre alt. Etwa 1,5% aller Menschen über 60 Jahre in NRW haben eine lebenslange Behinderung, von den schwerbehinderten alten Menschen (über 60 Jahre) 6,2%. Die Anzahl und der relative Anteil der Seniorinnen und Senioren mit lebenslanger Behinderung an der Bevölkerungsgruppe der alten wie der behinderten Menschen werden in den nächsten Jahrzehnten deutlich steigen. Dabei handelt es sich um eine „Normalisierung“ der Altersstruktur von Menschen mit lebenslanger Behinderung, eine nachholende Entwicklung im Vergleich zur Gesamt-bevölkerung. Die durchschnittliche Lebenserwartung beträgt z. B. für Männer mit geistiger Behinderung nach einer Studie für Westfalen für die Jahre 2007–2009 71,0 Jahre und für Frauen 72,8 Jahre. Sie ist trotz eines starken Anstiegs immer noch deutlich niedriger als die der Gesamtbevölkerung. Sowohl die allgemeinen Unterstützungsstrukturen in den Gemeinwesen wie die spezifischen für Menschen mit lebenslanger Behinderung müssen sich auf Anforderungen einstellen, die mit dieser demografischen Entwicklung verbunden sind. Die gegenüber einer familiären oder beruflichen Normalbiografie veränderten Lebensläufe und das Angewiesensein auf Unterstützung lassen die Herausforderungen, die mit dem Älterwerden für diesen Personenkreis einhergehen, allerdings in einem anderen Licht erscheinen. Auf alte Menschen mit lebenslanger Behinderung werden überwiegend negative Altersbilder projiziert (doppelte Stigmatisierung). Falls sie überhaupt gesellschaftlich wahrgenommen werden, werden Defizite konstatiert, werden sie sehr schnell den negativ bewerteten „gebrechlichen“ und nicht den „erfolgreichen“ Alten zugeordnet

Concise Synthesis of the Macrocyclic Core of Rhizopodin by a Heck Macrocyclization Strategy

A highly convergent synthesis of the central dimeric core of the potent antibiotic macrolide rhizopodin is reported. Notable features of the highly concise route include an effective preparation of the key C8-C22 building block based on an iridium-catalyzed Krische allylation and a chemoselective cross-coupling approach toward the macrocycle involving a highly advantageous Heck reaction for macrocyclization

Proliferative and anti-proliferative effects of titanium- and iron-based metallocene anti-cancer drugs

In previous work we have found that Cp2TiCl2 and its corresponding deriv. of tamoxifen, Titanocene tamoxifen, show an unexpected proliferative effect on hormone dependent breast cancer cells MCF-7. In order to check if this behavior is a general trend for titanocene derivs. we have tested two other titanocene derivs., Titanocene Y and Titanocene K, on this cell line. Interestingly, these two titanocene complexes behave in a totally different manner. Titanocene K is highly proliferative on MCF-7 cells even at low concns. (0.5 .mu.M), thus behave almost similarly to Cp2TiCl2. This proliferative effect is also obsd. in the presence of bovine serum albumin (BSA). In contrast, Titanocene Y alone has almost no effect on MCF-7 at a concn. of 10 .mu.M, but exhibits a significant dose dependent cytotoxic effect of up to 50% when incubated with BSA (20-50 .mu.g/mL). This confirms the crucial role played by the binding to serum proteins in the expression of the in vivo, cytotoxicity of the titanocene complexes. From the hydridolithiation reaction of 6-p-anisylfulvene with LiBEt3H followed by transmetallation with iron dichloride [bis-[(p-methoxy-benzyl)cyclopentadienyl]iron(II)] (Ferrocene Y) was synthesized. This complex, which was characterized by single crystal X-ray diffraction, contains the robust ferrocenyl unit instead of Ti assocd. with easily leaving groups such as chlorine and shows only a modest cytotoxicity against MCF-7 or MDA-MB-231 cells

Rhenium Complexes with Visible-Light-Induced Anticancer Activity

US National Institutes of Health [CA114046

Scientific background document in support of the development of a CCAMLR MPA in the Weddell Sea (Antarctica) – Version 2014

Germany intends to present the Scientific Committee the background document that provides the scientific basis for the evaluation of marine protected areas (MPAs) in the Weddell Sea. Please note, that the current state of the background document presents a comprehensive yet incomplete first version concerning chapters that have to be (further) developed or revised. The contents and structure of the document reflect also its main objectives, i.e. (i) to set out the general background and context of the establishment of MPAs, (ii) to describe the boundaries of the Weddell Sea MPA Planning Area, (iii) to inform on the data retrieval process, (iv) to provide - for the first time- a comprehensive, yet succinct, general description of the Weddell Sea ecosystem to reflect the state of the science, and additionally to present the results of the various preliminary scientific analyses that were carried out so far within the framework of the MPA Weddell Sea project, and finally (v) to describe future work beyond the development of the scientific basis for the evaluation of a Weddell Sea MPA

Scientific background document in support of the development of a CCAMLR MPA in the Weddell Sea (Antarctica) - Version 2015 - Part A: General context of the establishment of MPAs and background information on the Weddell Sea MPA planning area-

Germany intends to present the Working Group on Ecosystem Monitoring and Management (WG EMM) the background document that provides the scientific basis for the evaluation of a marine protected area (MPA) in the Weddell Sea planning area. The contents and structure of the whole document reflect its main objectives, i.e. to set out the general context of the establishment of MPAs and to provide the background information on the Weddell Sea MPA (WSMPA) planning area (Part A); to inform on the data retrieval process (Part B) and to describe the results of the scientific analyses and the MPA scenario development with the directly science-based aspects of the WSMPA proposal, i.e. the objectives and the boundaries and zones of the MPA (Part C). Here, the authors intend to update WG EMM on the current state of Part A of the document that has been presented at the meeting of the CCAMLR Scientific Committee in 2014. The Scientific Committee had welcomed and endorsed the scientific background document (SC-CAMLR-XXXIII/BG/02) as a foundation reference for the Weddell Sea MPA planning (SC-CAMLR-XXXIII, § 5.21). Part A contains (i) a synopsis in terms of the establishment of MPAs (chapter 1); (ii) a description of the boundaries of the WSMPA planning area (chapter 2); (iii) a comprehensive, yet succinct, general description of the Weddell Sea ecosystem (chapter 3); (iv) and finally a guidance regarding the future work beyond the development of the scientific basis for the evaluation of a WSMPA (chapter 4). Please note that the current state of Part A of the document presents a comprehensive yet incomplete version concerning chapters that have to be (further) developed or revised