Waveguide grating mirror in a fully suspended 10 meter Fabry-Perot cavity

We report on the first demonstration of a fully suspended 10m Fabry-Perot cavity incorporating a waveguide grating as the coupling mirror. The cavity was kept on resonance by reading out the length fluctuations via the Pound-Drever-Hall method and employing feedback to the laser frequency. From the achieved finesse of 790 the grating reflectivity was determined to exceed 99.2% at the laser wavelength of 1064\,nm, which is in good agreement with rigorous simulations. Our waveguide grating design was based on tantala and fused silica and included a ~20nm thin etch stop layer made of Al2O3 that allowed us to define the grating depth accurately during the fabrication process. Demonstrating stable operation of a waveguide grating featuring high reflectivity in a suspended low-noise cavity, our work paves the way for the potential application of waveguide gratings as mirrors in high-precision interferometry, for instance in future gravitational wave observatories

Michelson interferometer with diffractively-coupled arm resonators in second-order Littrow configuration

Michelson-type laser-interferometric gravitational-wave (GW) observatories employ very high light powers as well as transmissively- coupled Fabry-Perot arm resonators in order to realize high measurement sensitivities. Due to the absorption in the transmissive optics, high powers lead to thermal lensing and hence to thermal distortions of the laser beam profile, which sets a limit on the maximal light power employable in GW observatories. Here, we propose and realize a Michelson-type laser interferometer with arm resonators whose coupling components are all-reflective second-order Littrow gratings. In principle such gratings allow high finesse values of the resonators but avoid bulk transmission of the laser light and thus the corresponding thermal beam distortion. The gratings used have three diffraction orders, which leads to the creation of a second signal port. We theoretically analyze the signal response of the proposed topology and show that it is equivalent to a conventional Michelson-type interferometer. In our proof-of-principle experiment we generated phase-modulation signals inside the arm resonators and detected them simultaneously at the two signal ports. The sum signal was shown to be equivalent to a single-output-port Michelson interferometer with transmissively-coupled arm cavities, taking into account optical loss. The proposed and demonstrated topology is a possible approach for future all-reflective GW observatory designs

¿Qué leían los cruzados argentinos? : Las lecturas del nacionalismo católico a través de 'Cabildo' (1973-1976)

En el siguiente artículo se aborda la revista nacionalista católica Cabildo desde una perspectiva sensible a la historia intelectual. El objetivo es ampliar y completar, a partir de las lecturas promocionadas en las publicidades y de los libros reseñados, el universo de representaciones políticas y religiosas. Luego de presentar la revista, largamente estudiada por la historiografía, se analizan las publicidades identificando redes intelectuales locales, pero también transnacionales. En forma posterior se examinan tres reseñas dedicadas a la lectura de la historia, la ciencia ficción y la guerra contrarrevolucionaria. Se concluye que el nacionalismo católico, lejos de impugnar la modernidad en un nivel ontológico, trazó un diálogo práctico bajo la condición de corregir sus peligrosas derivas.En el següent article s'aborda la revista nacionalista catòlica Cabildo des d'una perspectiva sensible a la història intel·lectual. L'objectiu és ampliar i completar, a partir de les lectures promocionades en les publicitats i dels llibres ressenyats, l'univers de representacions polítiques i religioses. Després de presentar la revista, llargament estudiada per la historiografia, s'analitzen les publicitats tot identificant xarxes intel·lectuals locals, però també transnacionals. Més endavant s'examinen tres ressenyes dedicades a la lectura de la història, la ciència-ficció i la guerra contrarevolucionària. Es conclou que el nacionalisme catòlic, lluny d'impugnar la modernitat en un nivell ontològic, va traçar un diàleg pràctic sota la condició de corregir les seves perilloses derives.The following paper focuses on the Catholic nationalist magazine Cabildo from an Intellectual History standpoint. The aim is to expand and complete, from the reading matter promoted in its advertisements and the books reviewed, the universe of its political and religious representations. After a brief introduction to the magazine, long studied in the literature, the advertisements are analyzed and transnational as well as local intellectual networks are identified. Later, three book reviews, focusing on the interpretation of Argentine history, science fiction, and the counterrevolutionary war, are examined. It is concluded that, far from challenging modernity on an ontological level, Cabildo entered into a practical dialogue with it without accepting its dangerous deviations

Eco-aesthetic dimensions: Herbert Marcuse, ecollogy and art

In his last book, The Aesthetic Dimension (1978), Marcuse argued that a concern for aesthetics is justified when political change is unlikely. But the relation between aesthetics and politics is oblique: “Art cannot change the world, but it can contribute to changing the consciousness … of the men and women who could change the world.” (p. 33). Marcuse also linked his critique of capitalism to environmentalism in the early 1970s: “the violation of the Earth is a vital aspect of the counterrevolution.” (Ecology and Revolution, in The New Left and the 1960s, Collected Papers 3, 2005, p. 173). This article revisits Marcuse’s ideas on aesthetics and ecology, and reviews two recent art projects which engage their audiences in ecological issues: The Jetty Project (2014) by Wolfgang Weileder—which used recycled material and community participation to construct a temporary monument within a wider conservation project on the Tyne, N-E England—and Fracking Futures by HeHe (Helen Evans and Heiko Hansen)—which turned the interior of the gallery at FACT, Liverpool, into what appeared to be a fracking site. The aim is not to evaluate the projects, nor to test the efficacy of Marcuse’s ideas, more to ask again whether art has a role in a shift of attitude which might contribute to dealing with the political and economic causes of climate change

Investigation of mechanical losses of thin silicon flexures at low temperatures

The investigation of the mechanical loss of different silicon flexures in a temperature region from 5 to 300 K is presented. The flexures have been prepared by different fabrication techniques. A lowest mechanical loss of $3\times10^{-8}$ was observed for a 130 $\mu$m thick flexure at around 10 K. While the mechanical loss follows the thermoelastic predictions down to 50 K a difference can be observed at lower temperatures for different surface treatments. This surface loss will be limiting for all applications using silicon based oscillators at low temperatures. The extraction of a surface loss parameter using different results from our measurements and other references is presented. We focused on structures that are relevant for gravitational wave detectors. The surface loss parameter $\alpha_s$ = 0.5 pm was obtained. This reveals that the surface loss of silicon is significantly lower than the surface loss of fused silica.Comment: 16 pages, 7 figure

Educational inequalities in obesity: a multilevel analysis of survey data from cities in Latin America

Abstract Using newly harmonised individual-level data on health and socio-economic environments in Latin American cities (from the Salud Urbana en América Latina (SALURBAL) study), we assessed the association between obesity and education levels and explored potential effect modification of this association by city-level socio-economic development. Design This cross-sectional study used survey data collected between 2002 and 2017. Absolute and relative educational inequalities in obesity (BMI ≥ 30 kg/m2, derived from measured weight and height) were calculated first. Then, a two-level mixed-effects logistic regression was run to test for effect modification of the education–obesity association by city-level socio-economic development. All analyses were stratified by sex. Setting: One hundred seventy-six Latin American cities within eight countries (Brazil, Chile, Colombia, Costa Rica, El Salvador, Guatemala, Mexico and Peru). Results: Among women, 25 % were living with obesity and obesity was negatively associated with educational level (higher education–lower obesity) and this pattern was consistent across city-level socio-economic development. Among men, 18 % were living with obesity and there was a positive association between education and obesity (higher education–higher obesity) for men living in cities with lower levels of development, whereas for those living in cities with higher levels of development, the pattern was inverted and university education was protective of obesity. Conclusions: Among women, education was protective of obesity regardless, whereas among men, it was only protective in cities with higher levels of development. These divergent results suggest the need for sex- and city-specific interventions to reduce obesity prevalence and inequalities

Scientific Objectives of Einstein Telescope

The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.Comment: 18 pages, 4 figures, Plenary talk given at Amaldi Meeting, July 201

Preventing carbon nanoparticle-induced lung inflammation reduces antigen-specific sensitization and subsequent allergic reactions in a mouse model

BACKGROUND: Exposure of the airways to carbonaceous nanoparticles can contribute to the development of immune diseases both via the aggravation of the allergic immune response in sensitized individuals and by adjuvant mechanisms during the sensitization against allergens. The cellular and molecular mechanisms involved in these adverse pathways are not completely understood. We recently described that the reduction of carbon nanoparticle-induced lung inflammation by the application of the compatible solute ectoine reduced the aggravation of the allergic response in an animal system. In the current study we investigated the influence of carbon nanoparticles on the sensitization of animals to ovalbumin via the airways. Ectoine was used as a preventive strategy against nanoparticle-induced neutrophilic lung inflammation. METHODS: Balb/c mice were repetitively exposed to the antigen ovalbumin after induction of airway inflammation by carbon nanoparticles, either in the presence or in the absence of ectoine. Allergic sensitization was monitored by measurement of immunoglobulin levels and immune responses in lung and lung draining lymph nodes after challenge. Furthermore the role of dendritic cells in the effect of carbon nanoparticles was studied in vivo in the lymph nodes but also in vitro using bone marrow derived dendritic cells. RESULTS: Animals exposed to antigen in the presence of carbon nanoparticles showed increased effects with respect to ovalbumin sensitization, to the allergic airway inflammation after challenge, and to the specific T(H)2 response in the lymph nodes. The presence of ectoine during the sensitization significantly reduced these parameters. The number of antigen-loaded dendritic cells in the draining lymph nodes was identified as a possible cause for the adjuvant effect of the nanoparticles. In vitro assays indicate that the direct interaction of the particles with dendritic cells is not able to trigger CCR7 expression, while this endpoint is achieved by lung lavage fluid from nanoparticle-exposed animals. CONCLUSIONS: Using the intervention strategy of applying ectoine into the airways of animals we were able to demonstrate the relevance of neutrophilic lung inflammation for the adjuvant effect of carbon nanoparticles on allergic sensitization. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12989-015-0093-5) contains supplementary material, which is available to authorized users

PCNA dependent cellular activities tolerate dramatic perturbations in PCNA client interactions

Proliferating cell nuclear antigen (PCNA) is an essential cofactor for DNA replication and repair, recruiting multiple proteins to their sites of action. We examined the effects of the PCNA(S228I) mutation that causes PCNA-associated DNA repair disorder (PARD). Cells from individuals affected by PARD are sensitive to the PCNA inhibitors T3 and T2AA, showing that the S228I mutation has consequences for undamaged cells. Analysis of the binding between PCNA and PCNA-interacting proteins (PIPs) shows that the S228I change dramatically impairs the majority of these interactions, including that of Cdt1, DNMT1, PolD3(p66) and PolD4(p12). In contrast p21 largely retains the ability to bind PCNA(S228I). This property is conferred by the p21 PIP box sequence itself, which is both necessary and sufficient for PCNA(S228I) binding. Ubiquitination of PCNA is unaffected by the S228I change, which indirectly alters the structure of the inter-domain connecting loop. Despite the dramatic in vitro effects of the PARD mutation on PIP-degron binding, there are only minor alterations to the stability of p21 and Cdt1 in cells from affected individuals. Overall our data suggests that reduced affinity of PCNA(S228I) for specific clients causes subtle cellular defects in undamaged cells which likely contribute to the etiology of PARD