Practice Movements: The Politics of Non-sovereign Power

Practice movements, that is, forms of unorganized collective action, are a central site of politics. Their defining moments are that their goals are expressed in practices rather than in words, and that these “pre-ideological” practices aim at access to or redistribution of goods, whether material or symbolic, rather than at representation. They are transgression rather than resistance in that they transgress restrictions inherent in the material organization of space, property relations, status orders, and normative regulations, be they laws, morals, or customs. Practice movements are above all about access and participation rather than about autonomy, and thus have an ambiguous relation to the transformation of the status quo. Their politics are transformative and they can produce temporary or lasting changes in the material grounds or in the regulation of the everyday life of those who pursue them, and potentially of the normativity and the organization of the wider social order.

Newton’s Metaphysics of Space as God’s Emanative Effect

In several of his writings, Isaac Newton proposed that physical space is God’s “emanative effect” or “sensorium,” revealing something interesting about the metaphysics underlying his mathematical physics. Newton’s conjectures depart from Plato and Aristotle’s metaphysics of space and from classical and Cambridge Neoplatonism. Present-day philosophical concepts of supervenience clarify Newton’s ideas about space and offer a portrait of Newton not only as a mathematical physicist but an independent-minded rationalist philosopher.

Differential spatial and structural organization of the X chromosome underlies dosage compensation in C. elegans.

The adjustment of X-linked gene expression to the X chromosome copy number (dosage compensation [DC]) has been widely studied as a model of chromosome-wide gene regulation. In Caenorhabditis elegans, DC is achieved by twofold down-regulation of gene expression from both Xs in hermaphrodites. We show that in males, the single X chromosome interacts with nuclear pore proteins, while in hermaphrodites, the DC complex (DCC) impairs this interaction and alters X localization. Our results put forward a structural model of DC in which X-specific sequences locate the X chromosome in transcriptionally active domains in males, while the DCC prevents this in hermaphrodites.

From Ribbons to Networks: Hierarchical Organization of DNA-Grafted Supramolecular Polymers

DNA-grafted supramolecular polymers (SPs) allow the programmed organization of DNA in a highly regular, one-dimensional array. Oligonucleotides are arranged along the edges of pyrene-based helical polymers. Addition of complementary oligonucleotides triggers the assembly of individual nanoribbons resulting in the development of extended supramolecular networks. Network formation is enabled by cooperative coaxial stacking interactions of terminal GC base pairs. The process is accompanied by structural changes in the pyrene polymer core that can be followed spectroscopically. Network formation is reversible, and disassembly into individual ribbons is realized either via thermal denaturation or by addition of a DNA separator strand.

Optical Light Curve Observations to Determine Attitude States of Space Debris

The currently proposed space debris remediation measures include the active removal of large objects and “just in time” collision avoidance by deviating the objects using, e.g., ground-based lasers. Both techniques require precise knowledge of the attitude state and state changes of the target objects. In the former case, to devise methods to grapple the target by a tug spacecraft, in the latter, to precisely propagate the orbits of potential collision partners as disturbing forces like air drag and solar radiation pressure depend on the attitude of the objects. Non-resolving optical observations of the magnitude variations, so-called light curves, are a promising technique to determine rotation or tumbling rates and the orientations of the actual rotation axis of objects, as well as their temporal changes. The 1-meter telescope ZIMLAT of the Astronomical Institute of the University of Bern has been used to collect light curves of MEO and GEO objects for a considerable period of time. Recently, light curves of Low Earth Orbit (LEO) targets were acquired as well. We present different observation methods, including active tracking using a CCD subframe readout technique, and the use of a high-speed scientific CMOS camera. Technical challenges when tracking objects with poor orbit redictions, as well as different data reduction methods are addressed. Results from a survey of abandoned rocket upper stages in LEO, examples of abandoned payloads and observations of high area-to-mass ratio debris will be resented. Eventually, first results of the analysis of these light curves are provided.

Extraction of spin periods of space debris from optical light curves

The population of space debris increased drastically during the last years. These objects have become a great threat for active satellites. Because the relative velocities between space debris and satellites are high, space debris objects may destroy active satellites through collisions. Furthermore, collisions involving massive objects produce large number of fragments leading to significant growth of the space debris population. The long term evolution of the debris population is essentially driven by so-called catastrophic collisions. An effective remediation measure in order to stabilize the population in Low Earth Orbit (LEO) is therefore the removal of large, massive space debris. To remove these objects, not only precise orbits, but also more detailed information about their attitude states will be required. One important property of an object targeted for removal is its spin period, spin axis orientation and their change over time. Rotating objects will produce periodic brightness variations with frequencies which are related to the spin periods. Such a brightness variation over time is called a light curve. Collecting, but also processing light curves is challenging due to several reasons. Light curves may be undersampled, low frequency components due to phase angle and atmospheric extinction changes may be present, and beat frequencies may occur when the rotation period is close to a multiple of the sampling period. Depending on the method which is used to extract the frequencies, also method-specific properties have to be taken into account. The astronomical Institute of the University of Bern (AIUB) light curve database will be introduced, which contains more than 1,300 light curves acquired over more than seven years. We will discuss properties and reliability of different time series analysis methods tested and currently used by AIUB for the light curve processing. Extracted frequencies and reconstructed phases for some interesting targets, e.g. GLONASS satellites, for which also SLR data were available for the period confirmation, will be presented. Finally we will present the reconstructed phase and its evolution over time of a High-Area-to-Mass-Ratio (HAMR) object, which AIUB observed for several years.

Supramolecular Organization of Dye Molecules in Zeolite L Channels: Synthesis, Properties, and Composite Materials

Sequential insertion of different dyes into the 1D channels of zeolite L (ZL) leads to supramolecular sandwich structures and allows the formation of sophisticated antenna composites for light harvesting, transport, and trapping. The synthesis and properties of dye molecules, host materials, composites, and composites embedded in polymer matrices, including two- and three-color antenna systems, are described. Perylene diimide (PDI) dyes are an important class of chromophores and are of great interest for the synthesis of artificial antenna systems. They are especially well suited to advancing our understanding of the structure–transport relationship in ZL because their core fits tightly through the 12-ring channel opening. The substituents at both ends of the PDIs can be varied to a large extent without influencing their electronic absorption and fluorescence spectra. The intercalation/insertion of 17 PDIs, 2 terrylenes, and 1 quaterrylene into ZL are compared and their interactions with the inner surface of the ZL nanochannels discussed. ZL crystals of about 500 nm in size have been used because they meet the criteria that must be respected for the preparation of antenna composites for light harvesting, transport, and trapping. The photostability of dyes is considerably improved by inserting them into the ZL channels because the guests are protected by being confined. Plugging the channel entrances, so that the guests cannot escape into the environment is a prerequisite for achieving long-term stability of composites embedded in an organic matrix. Successful methods to achieve this goal are described. Finally, the embedding of dye–ZL composites in polymer matrices, while maintaining optical transparency, is reported. These results facilitate the rational design of advanced dye–zeolite composite materials and provide powerful tools for further developing and understanding artificial antenna systems, which are among the most fascinating subjects of current photochemistry and photophysics.

Cycling in the nucleus: regulation of RNA 3' processing and nuclear organization of replication-dependent histone genes.

The histones which pack new DNA during the S phase of animal cells are made from mRNAs that are cleaved at their 3' end but not polyadenylated. Some of the factors used in this reaction are unique to it while others are shared with the polyadenylation process that generates all other mRNAs. Recent work has begun to shed light on how the cell manages the assignment of these common components to the two 3' processing systems, and how it achieves their cell cycle-regulation and recruitment to the histone pre-mRNA. Moreover, recent and older findings reveal multiple connections between the nuclear organization of histone genes, their transcription and 3' end processing as well as the control of cell proliferation.

Preferences for the organization of long-term follow-up in adolescent and young adult cancer survivors.

PURPOSE As survival rates of adolescent and young adult (AYA) cancer patients increase, a growing number of AYA cancer survivors need follow-up care. However, there is little research on their preferences for follow-up care. We aimed to (1) describe AYA cancer survivors' preferences for the organization and content of follow-up care, (2) describe their preferences for different models of follow-up, and (3) investigate clinical and sociodemographic characteristics associated with preferences for the different models. METHODS AYA cancer survivors (diagnosed with cancer at age 16-25 years; ≥5 years after diagnosis) were identified through the Cancer Registry Zurich and Zug. Survivors completed a questionnaire on follow-up attendance, preferences for organizational aspects of follow-up care (what is important during follow-up, what should be included during appointments, what specialists should be involved, location), models of follow-up (telephone/questionnaire, general practitioner (GP), pediatric oncologist, medical oncologist, multidisciplinary team), and sociodemographic characteristics. Information on tumor and treatment was available through the Cancer Registry Zurich and Zug. RESULTS Of 389 contacted survivors, 160 (41.1 %) participated and 92 (57.5 %) reported still attending follow-up. Medical aspects of follow-up care were more important than general aspects (p < 0.001). Among different organizational models, follow-up by a medical oncologist was rated higher than all other models (p = 0.002). Non-attenders of follow-up rated GP-led follow-up significantly higher than attenders (p = 0.001). CONCLUSION Swiss AYA cancer survivors valued medical content of follow-up and showed a preference for medical oncologist-led follow-up. Implementation of different models of follow-up care might improve accessibility and attendance among AYA cancer survivors.

Organization of the equine immunoglobulin heavy chain constant region genes; III. Alignment of c mu, c gamma, c epsilon and c alpha genes.

Previous restriction analysis of cloned equine DNA and genomic DNA of equine peripheral blood mononuclear cells had indicated the existence of one c epsilon, one c alpha and up to six c gamma genes in the haploid equine genome. The c epsilon and c alpha genes have been aligned on a 30 kb DNA fragment in the order 5' c epsilon-c alpha 3'. Here we describe the alignment of the equine c mu and c gamma genes by deletion analysis of one IgM, four IgG and two equine light chain expressing heterohybridomas. This analysis establishes the existence of six c gamma genes per haploid genome. The genomic alignment of the cH-genes is 5' c mu/(/) c gamma 1/(/) c gamma 2/(/) c gamma 3/(/) c gamma 4/(/) c gamma 5/(/) c gamma 6/(/) c epsilon-c alpha 3', naming the c gamma genes according to their position relative to c mu. For three of the c gamma genes the corresponding IgG isotypes could be identified as IgGa for c gamma 1, IgG(T) for c gamma 3 and IgGb for c gamma 4.

GENETIC ORGANIZATION OF THE STRUCTURAL GENES FOR NITRATE REDUCTASE (TN5)

Nitrate reductase in Escherichia coli is a membrane-bound anaerobic enzyme that is repressed by oxygen and induced by nitrate. The genetic organization of the structural genes for the two larger subunits of nitrate reductase ((alpha) and (beta)) was determined by immunoprecipitation analysis of the formation of these proteins in nitrate reductase-deficient mutants resulting from transposon Tn5 mutagenesis. The results suggested that the genes encoding the (alpha) and (beta) subunits (narG and H) were arranged in an operon with transcription in the direction promoter(--->)(alpha)(--->)(beta). Segments of the chromosome containing the Tn5 inserts from several of the mutants were cloned into plasmid pBR322 and the positions of the transposons determined by restriction mapping. The Tn5 insertion sites were localized on two contiguous EcoRI fragments spanning about 6.6 kilobases of DNA. The narI gene (proposed to encode the (gamma) subunit) was positioned immediately downstream from the (beta)-gene (narH) by Southern analysis of Tn10 insertions into the narI locus. A Tn10 insertion into the narK locus, proposed to encode a nitrate-sensitive repressor of other anaerobic enzymes, was located about 1.5 kilobases upstream from the narGHI operon promoter. The narL locus, proposed to encode a nitrate-sensitive positive regulator of the narGHI operon and known to be genetically linked to the other nar genes, was demonstrated to lie outside a 19.3-kilobase region of the chromosome which encompasses the other nar genes. The physical limit of the narGHI promoter was defined by studying the effect of Tn5 insertions into a hybrid plasmid containing the functional operon. The points of origin of the coding regions for the (alpha) and (beta) genes were deduced by alignment of the chromosomal map of Tn5 insertion sites with the sizes of (alpha) and (beta) subunit fragments produced by plasmids carrying these Tn5 inserts in the nar operon. The coding region for the (alpha) subunit (143,000 daltons) begins about 250 nucleotides downstream from the deduced limit of the promoter region and includes about 4.0 kilobases of DNA; the region encoding (beta) (60,000 daltons) lies immediately downstream from the (alpha)-gene and is approximately 1.6 kilobases in length. The adjacent region encoding the (gamma) subunit (19,000 daltons) is approximately 0.5 kilobase in length. ^

THE ULTRASTRUCTURAL ORGANIZATION OF THE HYPOGLOSSAL NUCLEUS IN THE RAT (SYNAPTOLOGY, CRANIAL NERVES)

An ultrastructural study of the hypoglossal nucleus (XII) in the rat has revealed two distinct neuronal populations. Hypoglossal motoneurons comprised the largest population of neurons in XII and were identified following injection of horseradish peroxidase (HRP) into the tongue. Motoneurons were large (25-50(mu)m), multipolar in shape and distributed throughout XII. The nucleus was large, round and centrally located, and the cytoplasm was characterized by dense lamellar arrays of rough endoplasmic reticulum. In contrast, a second population of small (10-18(mu)m), round to oval shaped neurons was found restricted to the ventral and dorsolateral regions of XII. The nucleus was markedly invaginated and eccentric, the cytoplasm scant and filled with free ribosomes, and the absence of lamellar arrays of rough endoplasmic reticulum was conspicuous. Neurons of this type were never found to contain HRP reaction product. These results demonstrate that the hypoglossal nucleus does not consist solely of motoneurons, but includes a distinctly separate, presumably non-motoneuronal pool. Arguments are presented in favor of this second neuron population being interneurons. The functional significance of these findings in relation to tongue control is discussed. ^