744 research outputs found
A Kucha\v{r} Hypertime Formalism For Cylindrically Symmetric Spacetimes With Interacting Scalar Fields
The Kucha\v{r} canonical transformation for vacuum geometrodynamics in the
presence of cylindrical symmetry is applied to a general non-vacuum case. The
resulting constraints are highly non-linear and non-local in the momenta
conjugate to the Kucha\v{r} embedding variables. However, it is demonstrated
that the constraints can be solved for these momenta and thus the dynamics of
cylindrically symmetric models can be cast in a form suitable for the
construction of a hypertime functional Schr\"odinger equation.Comment: 5 pages, LaTeX, UBCTP-93-02
Somewhere in Europe (1947): locating Hungary within a shifting geopolitical landscape
Somewhere in Europe/Valahol Európában (Radványi, 1947) was one of the first films made in Hungary after 1945. Financed by the Hungarian Communist Party (MKP), it loudly proclaimed a broad European pertinence in an effort to privilege the universal narrative of childhoods disrupted by the war over narrowly national political concerns. The film’s story of a gang of half-starved children battling for survival in a bombed-out Central European landscape places it squarely within a transnational post-war film-making tradition. Similarities with both Italian neorealism and Soviet socialist realist cinema indicate a shared European experience of the war, but is also attributable to the international training and experience of the film’s personnel. The director Radványi had worked in the Italian industry, while the scriptwriter was the well-known film theorist Béla Balázs, who had worked in Weimar Germany and Soviet Russia. This article argues that in spite of its ostensible commitment to a communist and humanist ideology, the film gives an insight into the Hungarian national obsession with territorial integrity. Hungary’s participation in World War II on the side of the Axis, and its position as a defeated nation under Allied occupation, are seen to complicate the film text. This article contends that in spite its transnational flavour, the film’s focus on lost children wandering a borderless Europe suggests a preoccupation with the country’s uncertain position within a shifting geopolitical landscape. In turn, the film’s official reading by Nemeskürty shows an eagerness to accept the film’s representation of Hungary as a blameless victim of the war, and gives evidence of a need to insert a (false) break between the country’s wartime past as a member of the Axis, and the country’s 1968 present as a member of the Communist world order
Deformation heterogeneity study of a 6061-T6 aluminum alloy processed by equal channel angular pressing
Among the severe plastic deformation techniques, the equal channel angular pressing
(ECAP) has drastically improved the mechanical properties of the processed alloys. However,
information regarding friction phenomenon, which modifies the deformation at the surface and the
heterogeneity microstrain state produced by the process itself, is still scarce. In the present work, the
deformation heterogeneity and the friction effect, at the surface in the bulk material of the 6061-T6
aluminum alloy processed by ECAP, is presented and discussed. The residual stress (RS)
measurements were performed by means of X-Ray diffraction. By means of synchrotron diffraction,
volumetric sections of the ECAPed samples were characterized. Finite element analysis showed a
good agreement with the experimentally obtained residual stress and microhardness mapping
results. The study also showed that the highest deformation zones were located at the outer parts of
the deformed samples (top and bottom), while the inner zone showed strain oscillations of up to
49±2 MPa.Peer ReviewedPostprint (author's final draft
Using 3D Stringy Gravity to Understand the Thurston Conjecture
We present a string inspired 3D Euclidean field theory as the starting point
for a modified Ricci flow analysis of the Thurston conjecture. In addition to
the metric, the theory contains a dilaton, an antisymmetric tensor field and a
Maxwell-Chern Simons field. For constant dilaton, the theory appears to obey a
Birkhoff theorem which allows only nine possible classes of solutions,
depending on the signs of the parameters in the action. Eight of these
correspond to the eight Thurston geometries, while the ninth describes the
metric of a squashed three sphere. It therefore appears that one can construct
modified Ricci flow equations in which the topology of the geometry is encoded
in the parameters of an underlying field theory.Comment: 17 pages, Late
Seismic tomographic imaging of the Eastern Mediterranean Mantle: Implications for terminal-stage subduction, the uplift of Anatolia, and the development of the North Anatolian Fault
The Eastern Mediterranean captures the eastwest transition from active subduction of Earth'soldest oceanic lithosphere to continental collision, making it an ideal location to study terminalstagesubduction. Asthenospheric or subductionrelated processes are the main candidates for the region's ∼2kmuplift and Miocene volcanism; however, their relative importance is debated. To address these issues, wepresent new P and S wave relative arrivaltime tomographic models that reveal fast anomalies associatedwith an intact Aegean slab in the west, progressing to a fragmented, partially continental, Cyprean slabbelow central Anatolia. We resolve a gap between the Aegean and Cyprean slabs, and a horizontal tear in theCyprean slab below the Central Anatolian Volcanic Province. Below eastern Anatolia, the completelydetached “Bitlis” slab is characterized by fast wave speeds at ∼500 km depth. Assuming slab sinkingrates mirror ArabiaAnatolia convergence rates, the Bitlis slab's location indicates an Oligocene (∼26 Ma)breakoff. Results further reveal a strong velocity contrast across the North Anatolian Fault likelyrepresenting a 40–60 km decrease in lithospheric thickness from the Precambrian lithosphere north of thefault to a thinned Anatolian lithosphere in the south. Slow uppermostmantle wave speeds below activevolcanoes in eastern Anatolia, and ratios of P to S wave relative traveltimes, indicate a thin lithosphere andmelt contributions. Positive central and eastern Anatolian residual topography requires additional supportfrom hot/buoyant asthenosphere to maintain the 1–2 km elevation in addition to an almost absentlithospheric mantle. Smallscale fast velocity structures in the shallow mantle above the Bitlis slab maytherefore be drips of Anatolian lithospheric mantle
Management of tuberculosis by healthcare practitioners in Pakistan: A systematic review
Objective: To assess the quality of tuberculosis (TB) care in Pakistan, through determining comparison of healthcare practitioners’ knowledge and practices to national and international TB care guidelines. Methods: Studies reporting on knowledge, attitudes and practices of public and private practitioners with TB patients were selected through searching electronic databases and grey literature. Findings: Of 1458 reports, 20 full-texts were assessed, of which 11 met the eligibility and quality criteria; all studies focused on private sector care. Heterogeneity precluded meta-analysis. In 3 of 4 studies, over 50% of practitioners correctly identified a cough as the main TB symptom. However, 4 out of 6 studies showed practitioners’ compliance to be low (under 50%) for the use of sputum microscopy in diagnosis. The poorest quality care occurred in the later stages of treatment, with low compliance in prescribing practices for continuation-phase care and in monitoring and recording treatment progress, the latter of which is particularly critical for treatment success. Conclusion: TB care was variable and generally inadequate, with both a lack of knowledge and a small ‘know-do’ gap evident—practitioners did not use methods that they know they should use. A lack of recent evidence found suggests that the quality of current practices may not be fully captured and further research is needed, especially on non-allopathic, rural and public-sector contexts. Improved training of practitioners, greater availability of recommended diagnostic tools and expansion of public-private partnerships are suggestions for improving the quality of TB care in Pakistan
Cracking in asphalt materials
This chapter provides a comprehensive review of both laboratory characterization and modelling of bulk material fracture in asphalt mixtures. For the purpose of organization, this chapter is divided into a section on laboratory tests and a section on models. The laboratory characterization section is further subdivided on the basis of predominant loading conditions (monotonic vs. cyclic). The section on constitutive models is subdivided into two sections, the first one containing fracture mechanics based models for crack initiation and propagation that do not include material degradation due to cyclic loading conditions. The second section discusses phenomenological models that have been developed for crack growth through the use of dissipated energy and damage accumulation concepts. These latter models have the capability to simulate degradation of material capacity upon exceeding a threshold number of loading cycles.Peer ReviewedPostprint (author's final draft
Emancipation Day
80.7568.298 – “Emancipation Day”: Music by Dave Braham: Words by C. L. Stout: Wm. A. Pond: 1876: SATB. (2 copies
An innovative solution for earthquake resistance hybrid steel –concrete systems with replaceable dissipative steel links
In this work innovative hybrid coupled shear walls (HCSW) are considered, their design is discussed, their efficiency and limitations evaluated by means of nonlinear static (pushover) analysis. Different numbers of storeys, wall geometries and design assumptions are studied in order to give an overview of situations of interest in European seismic prone areas. The design of an experimental test regarding the performance of the connection of a seismic link embedded in a concrete shear wall is presented. This study is part of a larger research project named INNO-HYCO (INNOvative HYbrid and COmposite steel-concrete structural solutions for building in seismic area) funded by the European Commission
A comparison of three data-poor stock assessment methods for the pink spiny lobster fishery in Mauritania
Several data-poor stock assessment methods have recently been proposed and applied
to data-poor fisheries around the world. The Mauritanian pink spiny lobster fishery
has a long history of boom and bust dynamics, with large landings, stock collapse,
and years-long fishery closures, all happening several times. In this study, we have
used catch, fishing efforts, and length-frequency data (LFD) obtained from the fishery
in its most recent period of activity, 2015–2019, and historical annual catch records
starting in 2006 to fit three data-poor stock assessment methods. These were the
length-based Bayesian (LBB) method, which uses LFD exclusively, the Catch-only MSY
(CMSY) method, using annual catch data and assumptions about stock resilience, and
generalised depletion models in the R package CatDyn combined with Pella-Tomlinson
biomass dynamics in a hierarchical inference framework. All threemethods presented the
stock as overfished. The LBB method produced results that were very pessimistic about
stock status but whose reliability was affected by non-constant recruitment. The CMSY
method and the hierarchical combination of depletion and Pella-Tomlinson biomass
dynamics produced more comparable results, such as similar sustainable harvest rates,
but both were affected by large statistical uncertainty. Pella-Tomlinson dynamics in
particular demonstrated stock experiencing wide fluctuations in abundance. In spite of
uncertain estimates, a clear understanding of the status of the stock as overfished and
in need of a biomass rebuilding program emerged as management-useful guidance to
steer exploitation of this economically significant resource into sustainability.info:eu-repo/semantics/publishedVersio
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