599 research outputs found

    Politics and porn: how news media characterizes problems presented by deepfakes, Critical Studies in Media Communication

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    “Deepfake” is a form of machine learning that creates fake videos by superimposing the face of one person on to the body of another in a new video. The technology has been used to create non-consensual fake pornography and sexual imagery, but there is concern that it will soon be used for politically nefarious ends. This study seeks to understand how the news media has characterized the problem(s) presented by deepfakes. We used discourse analysis to examine news articles about deepfakes, finding that news media discuss the problems of deepfakes in four ways: as (too) easily produced and distributed; as creating false beliefs; as undermining the political process; and as non-consensual sexual content. We provide an overview of how news media position each problem followed by a discussion about the varying degrees of emphasis given to each problem and the implications this has for the public’s perception and construction of deepfakes

    ATLSÂź and damage control in spine trauma

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    Substantial inflammatory disturbances following major trauma have been found throughout the posttraumatic course of polytraumatized patients, which was confirmed in experimental models of trauma and in vitro settings. As a consequence, the principle of damage control surgery (DCS) has developed over the last two decades and has been successfully introduced in the treatment of severely injured patients. The aim of damage control surgery and orthopaedics (DCO) is to limit additional iatrogenic trauma in the vulnerable phase following major injury. Considering traumatic brain and acute lung injury, implants for quick stabilization like external fixators as well as decided surgical approaches with minimized potential for additional surgery-related impairment of the patient's immunologic state have been developed and used widely. It is obvious, that a similar approach should be undertaken in the case of spinal trauma in the polytraumatized patient. Yet, few data on damage control spine surgery are published to so far, controlled trials are missing and spinal injury is addressed only secondarily in the broadly used ATLSÂź polytrauma algorithm. This article reviews the literature on spine trauma assessment and treatment in the polytrauma setting, gives hints on how to assess the spine trauma patient regarding to the ATLSÂź protocol and recommendations on therapeutic strategies in spinal injury in the polytraumatized patient

    A nonlinear drift which leads to Îș\kappa-generalized distributions

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    We consider a system described by a Fokker-Planck equation with a new type of momentum-dependent drift coefficient which asymptotically decreases as −1/p-1/p for a large momentum pp. It is shown that the steady-state of this system is a Îș\kappa-generalized Gaussian distribution, which is a non-Gaussian distribution with a power-law tail.Comment: Submitted to EPJB. 8 pages, 2 figures, dedicated to the proceedings of APFA

    Late Pleistocene-Holocene alluvial stratigraphy of southern Baja California, Mexico

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    A late Pleistocene to Holocene alluvial stratigraphy has been established for the basins of La Paz and San JosĂ© del Cabo, in the southern tip of the Baja California peninsula, Mexico. Six discrete alluvial units (Qt1 through Qt6) were differentiated across the region using a combination of geomorphologic mapping, sedimentological analysis, and soil development. These criteria were supported using radiocarbon, optically stimulated luminescence and cosmogenic depth-profile geochronology. Major aggradation started shortly after ∌70 ka (Qt2), and buildup of the main depositional units ended at ∌10 ka (Qt4). After deposition of Qt4, increasing regional incision of older units and the progressive development of a channelized alluvial landscape coincide with deposition of Qt5 and Qt6 units in a second, incisional phase. All units consist of multiple 1–3 m thick alluvial packages deposited as upper-flow stage beds that represent individual storms. Main aggradational units (Qt2-Qt4) occurred across broad (>2 km) channels in the form of sheetflood deposition while incisional stage deposits are confined to channels of ∌0.5–2 km width. Continuous deposition inside the thicker (>10 m) pre-Qt5 units is demonstrated by closely spaced dates in vertical profiles. In a few places, disconformities between these major units are nevertheless evident and indicated by partly eroded buried soils. The described units feature sedimentological traits similar to historical deposits formed by large tropical cyclone events, but also include characteristics of upper-regime flow sedimentation not shown by historical sediments, like long (>10 m) wavelength antidunes and transverse ribs. We interpret the whole sequence as indicating discrete periods during the late Pleistocene and Holocene when climatic conditions allowed larger and more frequent tropical cyclone events than those observed historically. These discrete periods are associated with times when insolation at the tropics was higher than the present-day conditions, determined by precessional cycles, and modulated by the presence of El Niño-like conditions along the tropical and northeastern Pacific. The southern Baja California alluvial record is the first to document a precession-driven alluvial chronology for the region, and it constitutes a strong benchmark for discrimination of direct tropical influence on any other alluvial record in southwestern North America

    Interaction between superconducting vortices and Bloch wall in ferrite garnet film

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    Interaction between a Bloch wall in a ferrite-garnet film and a vortex in a superconductor is analyzed in the London approximation. Equilibrium distribution of vortices formed around the Bloch wall is calculated. The results agree quantitatively with magneto-optical experiment where an in-plane magnetized ferrite-garnet film placed on top of NbSe2 superconductor allows observation of individual vortices. In particular, our model can reproduce a counter-intuitive attraction observed between vortices and a Bloch wall having the opposite polarity. It is explained by magnetic charges appearing due to discontinuity of the in-plane magnetization across the wall.Comment: 4 pages, 5 figure

    Using Fill Terraces to Understand Incision Rates and Evolution of the Colorado River in Eastern Grand Canyon, Arizona

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    The incision and aggradation of the Colorado River in eastern Grand Canyon through middle to late Quaternary time can be traced in detail using well-exposed fill terraces dated by a combination of optically stimulated luminescence, uranium series, and cosmogenic nuclide dating. This fluvial history provides the best bedrock incision rate for this important landscape and highlights the complications and advantages of fill terrace records for understanding river long-profile evolution and incision. The use of fill terraces, as distinct from strath terraces, for calculating incision rates is complicated by the cyclic alluviation and incision they record. In the example of the Grand Canyon this has led to various rates being reported by different workers and rates that tend to be overestimates in shorter records. We illustrate that a meaningful long-term bedrock incision rate of 140 m/m.y. can be extracted from the Grand Canyon record by linking episodes when the Colorado River is floored on bedrock. Variable incision rates reported in the greater region may be, to some degree, due to inconsistent calculations. Our data also highlight that the Colorado River has been a mixed alluvial-bedrock river through both time and space and has been a bedrock river for less than half of its Pleistocene history. This strong temporal variation, combined with the varying bedrock the river encounters on its path, heightens the challenge of understanding the tectonic, climatic, and drainage integration controls on the form and evolution of the Colorado River’s long profile

    Temporal variations in Holocene slip rate along the central Garlock fault, Pilot Knob Valley, California

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    Average geologic slip rates along the central Garlock fault, in eastern California, are thought to have been relatively steady at 5-7 mm/yr since at least the Late Pleistocene, yet present-day rates inferred from geodetic velocity fields are indistinguishable from zero. We evaluate the possibility of non-steady slip over millennial timescales using displaced Late Holocene alluvium along the central Garlock fault in Pilot Knob Valley. Truncation of a Late Holocene alluvial fan deposit against a shutter ridge requires a minimum of 30-37 m of displacement since deposition of the fan; maximum allowable displacement is 43-50 m. The extent of soil development atop the fan surface and optically stimulated luminescence ages bracket fan deposition between 3.5 and 4.5 ka. Together, these data require that slip rates during the Late Holocene were ̃7-14 mm/yr, with a preferred rate of ̃11-13 mm/yr. Our results, in conjunction with previous estimates of displacement over the past ̃15 ka, require significant temporal variations in strain release along the Garlock fault and confirm previous suggestions that interactions among fault systems in eastern California give rise to alternating periods of fault activity and quiescence

    Evaluating the size and extent of paleolakes in central Tibet during the late Pleistocene

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    Subhorizontal lake shorelines allow a geodynamic test of the size and extent of a hypothesized paleolake in central Tibet, the East Qiangtang Lake (EQL), during the last interglacial period (marine isotope stage (MIS) 5e). Reconstructions based on relict lake deposits suggest that the EQL would have been ~400 m deep and over ~66,000 km2. Models of flexural rebound driven by lake recession predict that shorelines near the EQL center, at the present-day location of Siling Co, would have rebounded 60–90 m above their initial elevation. New 36Cl chronology of the highest relict shorelines around Siling Co indicates that they reflect lake levels between 110 and 190 ka. These shorelines, however, are presently >300 m below their predicted elevations, implying a substantially smaller water load. Our results reveal that the expansion of Tibetan lakes during MIS 5e was relatively limited. Instead, individual lakes were supplied by river networks, much as they are today

    DC-SCRIPT deficiency delays mouse mammary gland development and branching morphogenesis

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    Mammary glands are unique organs in which major adaptive changes occur in morphogenesis and development after birth. Breast cancer is the most common cancer and a major cause of mortality in females worldwide. We have previously identified the loss of expression of the transcription regulator DC-SCRIPT (Zfp366) as a prominent prognostic event in estrogen receptor positive breast cancer patients. DC-SCRIPT affects multiple transcriptional events in breast cancer cells, including estrogen and progesterone receptor-mediated transcription, and promotes CDKN2B-related cell cycle arrest. As loss of DC-SCRIPT expression appears an early event in breast cancer development, we here investigated the role of DC-SCRIPT in mammary gland development using wild-type and DC-SCRIPT knockout mice. Mice lacking DC-SCRIPT exhibited severe breeding problems and showed significant growth delay relative to littermate wild-type mice. Subsequent analysis revealed that DC-SCRIPT was expressed in mouse mammary epithelium and that DC-SCRIPT deficiency delayed mammary gland morphogenesis in vivo. Finally, analysis of 3D mammary gland organoid cultures confirmed that loss of DC-SCRIPT dramatically delayed mammary organoid branching in vitro. The study shows for the first time that DC-SCRIPT deficiency delays mammary gland morphogenesis in vivo and in vitro. These data define DC-SCRIPT as a novel modulator of mammary gland development

    Particle approximation of the one dimensional Keller-Segel equation, stability and rigidity of the blow-up

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    We investigate a particle system which is a discrete and deterministic approximation of the one-dimensional Keller-Segel equation with a logarithmic potential. The particle system is derived from the gradient flow of the homogeneous free energy written in Lagrangian coordinates. We focus on the description of the blow-up of the particle system, namely: the number of particles involved in the first aggregate, and the limiting profile of the rescaled system. We exhibit basins of stability for which the number of particles is critical, and we prove a weak rigidity result concerning the rescaled dynamics. This work is complemented with a detailed analysis of the case where only three particles interact
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