Luminescence Sensitivity of Rhine Valley Loess: Indicators of Source Variability?

Loess provides a valuable terrestrial record of past environmental conditions, including the dynamics and trajectories of air mass circulation responsible for dust transport. Here we explore variations in the luminescence sensitivity characteristics of sedimentary quartz and feldspar as possible tools for identifying changes in source down a loess-palaeosol sequence (LPS). Luminescence sensitivity is a rapidly measurable index which is the product of interplay between source lithology and the history of the quartz or feldspar clasts. Variations in sensitivity of down profile may therefore reflect changes in sediment provenance as well as other factors such as weathering through pedogenesis. We undertake an empirical investigation of the luminescence sensitivity of quartz and feldspar from different grain-size fractions from the Schwalbenberg LPS in the German Rhine valley. We compare samples from a 30 m core spanning the last full glacial cycle with samples of oxygen isotope stage (OIS) 3–2 age exposed within nearby profile. We find an overall inverse relationship between quartz and feldspar sensitivity, as well as variability in sensitivity between different quartz grain sizes. Statistical analyses yield a significant correlation between IR50 sensitivity from unprocessed sediments and clay content, and feldspar sensitivity and Si/Al ratios down the core. Since Si/Al ratios may indicate changes in provenance, the latter correlation suggests that IR50 measurements on unprocessed samples may be used to provide a reliable, rapid scan of source variability over millennial timescales.

Stratosphere-Mesosphere exchange: Long term changes and drivers

<p>The meridional overturning mass circulation in the middle atmosphere, i.e. the Brewer-Dobson circulation (BDC), was first discovered before decades based on the distribution of trace gases and a basic analytical concept of BDC has been derived using the transformed Eulerian mean equations. Since then, BDC is usually defined as consisting of a diffusive part, and an advective, residual mean circulation. In the vertical, BDC is separated into two branches – a shallow branch in the lower stratosphere and a deep branch higher in the middle atmosphere.<br />Climate model simulations robustly show that the advective BDC part accelerates in connection to the greenhouse gas-induced climate change and this acceleration dominates the middle atmospheric changes in climate model projections. A prominent quantity that is being studied as a proxy for advective BDC changes is the net tropical upwelling across the tropopause, which measures the amount of mass advected by residual circulation from the troposphere to the stratosphere per unit of time. The upper BDC branch received considerably less research attention than its shallow part, but features some striking phenomenon in the terrestrial atmosphere. It couples the stratosphere and mesosphere and is also responsible for a large portion of interhemispheric transport and coupling in the middle atmosphere.<br />In our research, for the first time, we produce a conceptual study of the advective stratosphere-mesosphere exchange. The analysis of advective exchange of mass between the stratosphere and mesosphere, i.e. the advective mass transport across the stratopause represents another step towards a better understanding of the structure of the upper BDC part and at the same time provides valuable insights into the relatively little-explored stratopause region. We investigate the variability and trends in mass fluxes from the stratosphere to the mesosphere and vice versa based on data from the EMAC-L90 model CCMI-1 simulation for the period 1960-2100. We develop an analytical method that allows us to attribute the changes of transport to causative factors such as acceleration of residual circulation, variable height of the stratopause, change of a geometric shape of the stratopause and changes in width of the upwelling and downwelling regions. The main driver of the increasing mass exchange between the stratosphere and the mesosphere is the faster circulation, however, the other terms are not negligible. The derived methodology offers the possibility of using an analogous procedure also for the tropopause in the future.</p>

A Place for Shadows: A Prolegomena to the Authorship Practices and Films of Joanna Margaret Paul

<p>This is an "authorship" study of New Zealand artist Joanna Margaret Paul, with specific reference to her "experimental film" works. Though I will draw on a wide range of theorists, my overall approach is what Laura Marks calls "intercultural cinema." For Marks the term "intercultural cinema" refers to a specific "genre" or "movement" of experimental films created by authors caught "between two or more cultural regimes of knowledge." Intercultural film-makers include feminist, queer, indigenous and immigrant authors (any "minority" which possesses its own "regime of knowledge" and makes experimental film) living in "Western metropolitan areas," whose dominant culture is capitalist, masculine, "hegemonic, white and Euro-American" (a second regime of knowledge). What draws intercultural cinema together (and indeed, one could argue, experimental film in general) is an oppositional stance toward capitalist ideology, the commodification of the art object and the uniformity of classical narrative forms. As David Bordwell and Kristen Thompson write, experimental films are "often deliberate attempts to undercut the conventions of commercial narrative filmmaking" and, as Marks writes, intercultural cinema "flows against waves of economic neocolonialism," and is "suspicious of mass circulation... [as] making commercial cinema still involves significant compromises."</p>

A Place for Shadows: A Prolegomena to the Authorship Practices and Films of Joanna Margaret Paul

<p>This is an "authorship" study of New Zealand artist Joanna Margaret Paul, with specific reference to her "experimental film" works. Though I will draw on a wide range of theorists, my overall approach is what Laura Marks calls "intercultural cinema." For Marks the term "intercultural cinema" refers to a specific "genre" or "movement" of experimental films created by authors caught "between two or more cultural regimes of knowledge." Intercultural film-makers include feminist, queer, indigenous and immigrant authors (any "minority" which possesses its own "regime of knowledge" and makes experimental film) living in "Western metropolitan areas," whose dominant culture is capitalist, masculine, "hegemonic, white and Euro-American" (a second regime of knowledge). What draws intercultural cinema together (and indeed, one could argue, experimental film in general) is an oppositional stance toward capitalist ideology, the commodification of the art object and the uniformity of classical narrative forms. As David Bordwell and Kristen Thompson write, experimental films are "often deliberate attempts to undercut the conventions of commercial narrative filmmaking" and, as Marks writes, intercultural cinema "flows against waves of economic neocolonialism," and is "suspicious of mass circulation... [as] making commercial cinema still involves significant compromises."</p>

A Dissection of the Topographic Effects from Eurasia and North America on the Isentropic Meridional Mass Circulation in Northern Winter

The topographic dynamical effect from Eurasia (EA_Topo) and North America (NA_Topo) on the winter isentropic meridional mass circulation (IMMC) is investigated using the WACCM. The independent effect of EA_Topo and that of NA_Topo, with the former much stronger, are both to strengthen the IMMC that is composed of the lower equatorward cold air branch (CB) and the upper poleward warm air branch in the extratropical tropopshere (WB_TR) and stratosphere (WB_ST). Further investigation of the individual contributions from changes in stationary vs. transient and zonal-mean flow vs. waves reveals that, due to the topography-forced mass redistribution, changes in the low-level meridional pressure gradient force a zonal-mean counter-clockwise/ clockwise meridional cell in the southern/northern side of topography. This weakens/strengthens the IMMC south/north of 30°N from the troposphere to lower stratosphere, acting as a dominant contributor to the IMMC changes south of 50°N. Meanwhile, the EA/NA_Topo-forced amplification of stationary waves constructively interacts with those determined by land-sea contrast, making the dominant/minor contributions to the strengthening of CB and WB_TR north of 50°N. The related increase in the upward wave propagation further dominates the WB_ST strengthening in the subpolar region. Meanwhile, transient eddy activities are depressed by EA/NA_Topo along with the weakened background westerly, which partly-offset/dominate-over the contribution from stationary flow in midlatitudes and subpolar region. The coexistence of the other topography (NA/EA_Topo) yields destructive mutual interferrence, which can weaken/offset the independent-EA/NA_Topo-forced meridional mass transport mainly via changing the zonal-mean as well as the downstream wave pattern of mass and meridional wind.

Literature and Photography in Italy

Since its invention in 1839, photography—its aesthetics, practices, and product—has incited, inspired, and occupied Italian literary writing. Both literature and photography in Italy have responded to social and cultural changes occurring in the country from photography’s first arrival and since Italian unification in 1861. Literature’s relation to photography, therefore, can be understood by looking at the country’s connection to modernity and to its interlinks with the powerful aesthetic and visual perspective typical of Italian culture. Through photography, fiction, non-fiction prose, and poetry have dynamically and often ambiguously engaged discourses and reflections on reality, authenticity, and subjectivity. Such a relationship has offered a multitude of imaginary, emotional, and stylistic possibilities that have implied a challenge to literary realism as well as to photographic claim of truth and objectivity. Early daguerreotype plates of classical ruins, architecture, and landscapes were central to the first creative stage that joined photographic images and written words. At the end of the 19th century, during Italy’s transition from a pre-industrial age to an industrial one, photography appeared to embody the ideal model of that objective relationship to reality longed for by Positivism. The potential power of the camera to record the world also enchanted the veristi writers who established a relationship between resistance and acceptance with photographic image and practice. Concerns about the power of photography to alter the human perception of reality persisted into the 20th century. Nevertheless, the interrelation between literary texts and photography offered further viewpoints that multiplied or expanded perceptions of events, places, and people. Writers and artists also creatively and subversively exploited this relationship, especially thanks to modern printing techniques. During the Fascist period, at a time of crucial cultural transformation and modernization, photography became particularly instrumental in promulgating the regime’s ideology. Through mass circulation of popular illustrated periodicals, photographs also entered sophisticated photo-textual collaborations that developed further in postwar Italy. The documentary nature of the photographic image was challenged during the neorealist period and in diverse post–World War II literary works. At the same time, especially since the 1950s, Italian literature amplified earlier patterns of fictional investigations, and photography entered more dynamically into discourses and reflections on subjectivity, memory, and language. Following the emergence of international theoretical approaches to photography in the 1970s and 1980s, Italian literature engaged more critically with theory to investigate the social and political impact of photography, as well as its historical and artistic significance. The creative pairing of the photograph’s capacity to offer precise details of the real and simultaneously provoke a significant degree of referential uncertainty, in particular through digital technology, has continued to inspire Italian writers and bring changes in contemporary imaginative reproduction.