Planck LFI flight model feed horns

this paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/jinst The Low Frequency Instrument is optically interfaced with the ESA Planck telescope through 11 corrugated feed horns each connected to the Radiometer Chain Assembly (RCA). This paper describes the design, the manufacturing and the testing of the flight model feed horns. They have been designed to optimize the LFI optical interfaces taking into account the tight mechanical requirements imposed by the Planck focal plane layout. All the eleven units have been successfully tested and integrated with the Ortho Mode transducers.Comment: This is an author-created, un-copyedited version of an article accepted for publication in JINST. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher authenticated version is available online at 10.1088/1748-0221/4/12/T1200

Good practice learning and teaching for sustainability in higher education

Over the past 30 years, sustainable development has emerged as the imperative for the 21st Century in response to global challenges such as pollution, biodiversity loss, and social inequality, to name but a few. Universities play a critical role in equipping graduates with the capabilities and knowledge to respond to issues in increasingly complex local and global systems. While the case for education for sustainability (EfS) in higher education (HE) is well researched, what constitutes quality learning and teaching (L&T) practice for sustainability needs further exploration. Through a qualitative, multiple case study inquiry of four university level courses, this dissertation explores what is unique to the learning experience and delivery of EfS in HE and what ‘good practice’ L&T in EfS should involve based on the accounts of learners and teachers in the case study courses. This research makes an original contribution to knowledge by combining existing theory of good practice EfS with empirical research using participant observation, learner surveys and focus groups, and interviews with educators to better understand what needs to be considered in course design and delivery of EfS based on lived experience of L&T in EfS. The research found that good practice is learner-centred. The empirical data validates existing theory and the findings provide insight into factors such as teacher passion, learner empowerment and reflexivity to facilitate deep, ongoing learning

Electrophysiological characterization of contact sites in brain mitochondria.

From morphological and biochemical studies it has been recognized that the regions where the outer and inner membranes of mitochondria come in close contact (contact sites) can be the route mechanism through which mitochondria interact directly with the cytoplasm. We have studied these regions electrophysiologically with the patch clamp technique, with the aim of understanding if this direct interaction is mediated by high conductance ion channels similar to the channel already detected in the inner membrane of mitochondria (Sorgato M. C., Keller, B. U., and Stühmer, W. (1987) Nature 330, 498-500). Contact sites isolated from rat brain mitochondria were thus incorporated into liposomes subsequently enlarged sufficiently to be patch clamped. This study shows that these particular fractions contain ion channels with conductances ranging from approximately 5 picosiemens to 1 nanosiemens (in symmetrical 150 mM KCl). Most of these channels are not voltage-dependent and can be open at physiological potentials sustained by respiring mitochondria. The lack of voltage sensitivity seems not to be the outcome of methodological artifacts, as voltage-gated channels are detected in giant liposomes containing either the outer mitochondrial membrane or a partially purified fraction of the inner mitochondrial membrane. These data therefore indicate that channels present in mitochondrial contact sites have properties which render them amenable to perform several of the functions hypothesized for these regions, particularly that of translocating macromolecules from the cytoplasm to the matrix of mitochondria

Planck-LFI radiometers' spectral response

The Low Frequency Instrument (LFI) is an array of pseudo-correlation radiometers on board the Planck satellite, the ESA mission dedicated to precision measurements of the Cosmic Microwave Background. The LFI covers three bands centred at 30, 44 and 70 GHz, with a goal bandwidth of 20% of the central frequency. The characterization of the broadband frequency response of each radiometer is necessary to understand and correct for systematic effects, particularly those related to foreground residuals and polarization measurements. In this paper we present the measured band shape of all the LFI channels and discuss the methods adopted for their estimation. The spectral characterization of each radiometer was obtained by combining the measured spectral response of individual units through a dedicated RF model of the LFI receiver scheme. As a consistency check, we also attempted end-to-end spectral measurements of the integrated radiometer chain in a cryogenic chamber. However, due to systematic effects in the measurement setup, only qualitative results were obtained from these tests. The measured LFI bandpasses exhibit a moderate level of ripple, compatible with the instrument scientific requirements.Comment: 16 pages, 9 figures, this paper is part of the Prelaunch status LFI papers published on JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/jins

High Performances Corrugated Feed Horns for Space Applications at Millimetre Wavelengths

We report on the design, fabrication and testing of a set of high performance corrugated feed horns at 30 GHz, 70 GHz and 100 GHz, built as advanced prototypes for the Low Frequency Instrument (LFI) of the ESA Planck mission. The electromagnetic designs include linear (100 GHz) and dual shaped (30 and 70 GHz) profiles. Fabrication has been achieved by direct machining at 30 GHz, and by electro-formation at higher frequencies. The measured performances on side lobes and return loss meet the stringent Planck requirements over the large (20%) instrument bandwidth. Moreover, the advantage in terms of main lobe shape and side lobes levels of the dual profiled designs has been demonstrated.Comment: 16 pages, 7 figures, accepted for publication in Experimental Astronom

Change and Persistence, Proceedings of the International Conference, Tunis, 12-13 November 2013

This publication is based on the proceedings of an international conference entitled ‘Arab Revolutions and Beyond: Change and Persistence’, which was held in the framework of a multilateral project called ‘Challenges and Transformations in the Wake of the Arab Spring’ (2012-2014). The project is funded by the DAAD (German Academic Exchange Service) and based upon the longstanding partnership between Cairo University in Egypt and Freie Universität Berlin in Germany, specifically between the EuroMed Study Program at the Faculty of Economics and Political Sciences (FEPS) and the Centre for Middle Eastern and North African Politics at Otto-Suhr-Institute, Department for Political and Social Sciences. Dieser Sammelband ist ein Ergebnis der internationalen Tunis-Konferenz "Arab Revolutions and Beyond: Change and Persistence", die im Rahmen des multinationalen DAAD-Projekts "Challenges and Transformations in the Wake of the Arab Spring" im November 2013 stattfand. Neben Kolleg_innen der Universität Kairo, mit der bereits eine langjährige Partnerschaft besteht, sind auch Nachwuchsforscher_innen aus Tunesien, Libyen, Jordanien und weiteren Arabischen Staaten beteiligt. Das Projekt stellt sich den Herausforderungen, welche sich durch die politischen und sozialen Umbrüche in der Region für die akademische Bildung, v.a. in den Sozialwissenschaften ergeben haben. Hieraus soll ein produktiver Dialog über theoretische, methodische und thematische Felder der Sozialwissenschaften eröffnet werden, um die Strukturen von Forschung und Lehre dauerhaft zu verbessern.This publication is based on the proceedings of an international conference entitled ‘Arab Revolutions and Beyond: Change and Persistence’, which was held in the framework of a multilateral project called ‘Challenges and Transformations in the Wake of the Arab Spring’ (2012-2014). The project is funded by the DAAD (German Academic Exchange Service) and based upon the longstanding partnership between Cairo University in Egypt and Freie Universität Berlin in Germany, specifically between the EuroMed Study Program at the Faculty of Economics and Political Sciences (FEPS) and the Centre for Middle Eastern and North African Politics at Otto-Suhr-Institute, Department for Political and Social Sciences. The project addresses the challenges of current political and social transformations and their ramifications for higher education and the social sciences in Egypt and the region. The overarching objective of the project is to enter a productive dialogue on theories, methodologies and topics in social science research among Arab and German researchers. At the same time, we aim to improve teaching and research structures in the social sciences in a sustainable and efficient way. This will build students’ and teachers’ capacities on both shores of the Mediterranean and at the same time strengthen institutional efforts to promote the role of social sciences in the current transformations

Domesticação de paisagens utilizando sistemas agroflorestais no Alto Vale do Ribeira (PR/SP) e suas implicações para a conservação ambiental.

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Planck-LFI: Design and Performance of the 4 Kelvin Reference Load Unit

The LFI radiometers use a pseudo-correlation design where the signal from the sky is continuously compared with a stable reference signal, provided by a cryogenic reference load system. The reference unit is composed by small pyramidal horns, one for each radiometer, 22 in total, facing small absorbing targets, made of a commercial resin ECCOSORB CR (TM), cooled to approximately 4.5 K. Horns and targets are separated by a small gap to allow thermal decoupling. Target and horn design is optimized for each of the LFI bands, centered at 70, 44 and 30 GHz. Pyramidal horns are either machined inside the radiometer 20K module or connected via external electro-formed bended waveguides. The requirement of high stability of the reference signal imposed a careful design for the radiometric and thermal properties of the loads. Materials used for the manufacturing have been characterized for thermal, RF and mechanical properties. We describe in this paper the design and the performance of the reference system.Comment: This is an author-created, un-copyedited version of an article accepted for publication in JINST. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher authenticated version is available online at [10.1088/1748-0221/4/12/T12006]. 14 pages, 34 figure

Precise Measurement of Sigma Beam Asymmetry for Positive Pion Photoproduction on the Proton from 800 to 1500 Mev

The Sigma beam asymmetry for positive pion photoproduction on the proton has been measured over an angular range of 40-170 deg at photon energies from 0.8 to 1.5 GeV. The resulting data set includes 237 accurate points, 136 of these belonging to an almost unexplored domain above 1.05 GeV. Data of such high precision provide severe constraints for partial wave analyses. The influence of this experiment on the GW multipole analysis is demonstrated. Significant changes are found in multipoles connected to the S31(1620) and P13(1720) resonances. Comparisons using the MAID analysis are also presented.Comment: 11 pages, 4 eps figures. to be published in Physics Letters