Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars

Voids and hollow spheroids between ∼1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302-305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or the other form. The spheroids have 1-4 mm thick walls and appear relatively dark-toned in all cases, some with a reddish hue. Only one hollow spheroid (Winnipesaukee, sol 653) was analyzed for composition, appearing mafic (Fe-rich), in contrast to the relatively felsic host rock. The interior surface of the spheroid appears to have a similar composition to the exterior with the possible exceptions of being more hydrated and slightly depleted in Fe and K. Origins of the spheroids as Martian tektites or volcanic bombs appear unlikely due to their hollow and relatively fragile nature and the absence of in-place clearly igneous rocks. A more likely explanation to both the voids and the hollow spheroids is reaction of reduced iron with oxidizing groundwater followed by some re-precipitation as cemented rind concretions at a chemical reaction front. Although some terrestrial concretion analogs are produced from a precursor siderite or pyrite, diagenetic minerals could also be direct precipitates for other terrestrial concretions. The Gale sediments differ from terrestrial sandstones in their high initial iron content, perhaps facilitating a higher occurrence of such diagenetic reactions

Consilient Discrepancy: Porosity and Atmosphere in Cinema and Architecture

Cinema constitutes a way of looking at the world, at a world – its aspect, its appearance; but it also presents how that world looks, its prospect – by the prospective glance it throws back toward us. The “look” of a film – its mood, ambiance or atmosphere – eclipses formal and aesthetics registers. It is fundamentally world-forming, and therefore both cosmogonic and ethical: cosmogonic because it produces a world in the midst of, and as, the temporality that devolves through its passage; and ethical because the world it brings about is an inhabited world, a conjugation of people and place that constructs particular ways of being-there-together. The premise here is that atmosphere, ambiance and mood have never been vague categories for cinema and need not be for architecture: rather, that they are in fact producible through deliberate organizational strategies – kinematic and narrative in film, tectonic and material in architecture – according to what might be called “consilient discrepancy” – the coexistence of disseveral systems in unaligned multiplicity that, while never fusing, resonate to produce emergent conditions. Cinema offers architecture an accessible and instructive instance of such consilient discrepancy, because, in it, atmosphere is more fully captured and the conditions that create it more evidently analyzable. To that extent, cinema provides architecture with comparative grounds for engaging with atmosphere through a properly tectonic practice that can potentially enrich the design and experience of architecture. Consilient discrepancy is evident across multiple registers in film. It can function at the level of narrative, space and time and thus puts into question verisimilitude, causality, situational and durational veracity. An example of this is the constitutive disjunctions of Jean-Luc Godard’s jump cut montage where sampled film sequences, film and photographic stills, texts and citations, ambient sound, spoken word and music, build into complex assemblages of sense (Histoire(s) du Cinema, 1998). It is evident in Nicholas Roeg’s multiple, simultaneous temporalities where past and future events interpenetrate and mutually condition the narrative present (Bad Timing, 1980). Similarly, we can find it in Michelangelo Antonioni’s sequence shots that traverse multiple timeframes across the same space – a technique that enables past and present to communicate and amplify the affective, foundational value of the unseen and off-frame (The Passenger, 1975). Another example would be David Lynch’s labyrinthine existential settings, constituted of interminable slippages between indeterminable and infinitely potentialized spaces of dreams, imagination, memory and reality (Mulholland Drive, 2001). Likewise, we could cite Michael Hanake’s persistent displacement of causality and verisimilitude through ambiguous narrative viewpoints (Caché, 2005), and Roy Andersson’s radically liminal settings and characters whose lives constitute larval pre- and/or posthuman states of existence (A Pigeon Sat on a Branch Reflecting on Existence, 2014). This paper will foreground two foundational characteristics of atmosphere in cinema, as evident in the works just cited, and explore their applicability to architecture. The first characteristic is the consilient discrepancy outlined here by way of introduction, and the second, related characteristic, is a spatiality of porosity and occlusion. The provisional aim of comparing cinema and architecture according to this tectonic logic is to go beyond typical ways of understanding cinema’s formal engagement with architecture. For this purpose, a detailed analysis of Béla Tarr’s film Werckmeister Harmonies (2000) will serve as a case study for how the medium of cinema generates atmosphere, ambiance and mood through visual language. This will be followed by a similarly detailed consideration of concomitant qualities created in two recent works by the architects Flores Prats, the Mills Museum and Casal Balaguer. Functioning as exemplars of how cinematic qualities can be made manifest in architecture, these precedents will further substantiate the cinematic–architectonic proposition ventured in this paper

Centimeter to Decimeter Size Spherical and Cylindrical Features in Gale Crater Sediments

The Curiosity rover traverse in Gale crater has explored a large series of sedimentary deposits in an ancient lake on Mars. Over the nine kilometers of traverse a recurrent observation has been southward-dipping sedimentary strata, from Shaler at the edge of Yellowknife Bay to the striated units near the Kimberley. Within the sedimentary strata cm- to decimeter- size hollow spheroidal objects and some apparent cylindrical objects have been observed. These features have not been seen by previous landed missions. The first of these were observed on sol 122 in the Gillespie Lake member at Yellowknife Bay. Additional hollow features were observed in the Point Lake outcrop in the same area. More recently a spherical and apparently hollow object, Winnipesaukee, was observed by ChemCam and Mastcam on sol 653. Here we describe the settings, morphology, and associated compositions, and we discuss possible origins of these objects

Silica nanofibrous membranes for the separation of heterogeneous azeotropes

Nanofibrous materials produced through electrospinning are characterized by a high porosity, large specific surface area, and high pore interconnectivity and, therefore, show potential for, e.g., separation and filtration. The development of more inert nanofibers with higher thermal and chemical resistance extends the application field to high-end purification. Silica nanofibrous membranes produced by direct electrospinning of a sol-gel solution without a sacrificing carrier, starting from tetraethoxysilane, meet these challenging requirements. After electrospinning the membrane is highly hydrophobic. Storage under dry conditions preserves this property. Oppositely, a superhydrophilic membrane is obtained by storage under high humidity (month scale). This switch is caused by the reaction of ethoxy groups, present due to incomplete hydrolysis of the precursor, with moisture in the air, resulting in an increased amount of silanol groups. This transition can be accelerated to hour scale by applying a heat treatment, with the additional increase in cross-linking density for temperatures above 400 degrees C, enabling applications that make use of hydrophobic and hydrophilic membranes by tuning the functionalization. It is showcased that upon designing the water repellent or absorbing nature of the silica material, fast gravity-driven membrane separation of heterogeneous azeotropes can be achieved

Search for gravitational waves associated with the InterPlanetary Network short gamma ray bursts

We outline the scientific motivation behind a search for gravitational waves associated with short gamma ray bursts detected by the InterPlanetary Network (IPN) during LIGO's fifth science run and Virgo's first science run. The IPN localisation of short gamma ray bursts is limited to extended error boxes of different shapes and sizes and a search on these error boxes poses a series of challenges for data analysis. We will discuss these challenges and outline the methods to optimise the search over these error boxes.Comment: Methods paper; Proceedings for Eduardo Amaldi 9 Conference on Gravitational Waves, July 2011, Cardiff, U

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom

A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007

We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access area to figures, tables at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000

Is the northern high-latitude land-based CO2 sink weakening?

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 25 (2011): GB3018, doi:10.1029/2010GB003813.Studies indicate that, historically, terrestrial ecosystems of the northern high-latitude region may have been responsible for up to 60% of the global net land-based sink for atmospheric CO2. However, these regions have recently experienced remarkable modification of the major driving forces of the carbon cycle, including surface air temperature warming that is significantly greater than the global average and associated increases in the frequency and severity of disturbances. Whether Arctic tundra and boreal forest ecosystems will continue to sequester atmospheric CO2 in the face of these dramatic changes is unknown. Here we show the results of model simulations that estimate a 41 Tg C yr−1 sink in the boreal land regions from 1997 to 2006, which represents a 73% reduction in the strength of the sink estimated for previous decades in the late 20th century. Our results suggest that CO2 uptake by the region in previous decades may not be as strong as previously estimated. The recent decline in sink strength is the combined result of (1) weakening sinks due to warming-induced increases in soil organic matter decomposition and (2) strengthening sources from pyrogenic CO2 emissions as a result of the substantial area of boreal forest burned in wildfires across the region in recent years. Such changes create positive feedbacks to the climate system that accelerate global warming, putting further pressure on emission reductions to achieve atmospheric stabilization targets.This study was supported through grants provided as part of the Arctic System Science Program (NSF OPP‐ 0531047), the North American Carbon Program (NASA NNG05GD25G), and the Bonanza Creek Long‐Term Ecological Program (funded jointly by NSF grant DEB‐0423442 and USDA Forest Service, Pacific Northwest Research Station grant PNW01‐JV11261952‐231)

Swift follow-up observations of candidate gravitational-wave transient events

We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors and their candidate sky locations were observed by the Swift observatory. Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge". With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.Comment: Submitted for publication 2012 May 25, accepted 2012 October 25, published 2012 November 21, in ApJS, 203, 28 ( http://stacks.iop.org/0067-0049/203/28 ); 14 pages, 3 figures, 6 tables; LIGO-P1100038; Science summary at http://www.ligo.org/science/Publication-S6LVSwift/index.php ; Public access area to figures, tables at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p110003