2,154 research outputs found

    MFV SUSY: A Natural Theory for R-Parity Violation

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    We present an alternative approach to low-energy supersymmetry. Instead of imposing R-parity we apply the minimal flavor violation (MFV) hypothesis to the R-parity violating MSSM. In this framework, which we call MFV SUSY, squarks can be light and the proton long lived without producing missing energy signals at the LHC. Our approach differs from that of Nikolidakis and Smith in that we impose holomorphy on the MFV spurions. The resulting model is highly constrained and R-parity emerges as an accidental approximate symmetry of the low-energy Lagrangian. The size of the small R-parity violating terms is determined by the flavor parameters, and in the absence of neutrino masses there is only one renormalizable R-parity violating interaction: the baryon-number violating uˉdˉdˉ\bar{u}\bar{d}\bar{d} superpotential term. Low energy observables (proton decay, dinucleon decay and n−nˉn-\bar{n} oscillation) pose only mild constraints on the parameter space. LHC phenomenology will depend on whether the LSP is a squark, neutralino, chargino or slepton. If the LSP is a squark it will have prompt decays, explaining the non-observation of events with missing transverse energy at the LHC.Comment: 41 pages, 14 figures; v3: minor corrections, matches published versio

    Evidence That Luminant and Equiluminant Motion Signals Are Integrated by Directionally Selective Mechanisms

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    Three experiments tested whether motion information for nonequiluminant (luminant) and equiluminant dots affects direction judgments when both types of stimuli are moving simultaneously in the same display. The motion directions for the two sets of dots were manipulated to produce four direction differences (0°, 30°, 60°, and 90°). The equiluminant dots were moved in a perfectly correlated fashion, but the percentage of correlated motion for the luminant dots was varied. When subjects judged whether the directions of the equiluminant and luminant dots were the same or different, performance for the conditions with 0°, 60°, and 90° difference improved as the percentage of correlated luminant motion increased. The same result occurred for a control display that contained two sets of luminant dots. However, for the 30° difference, performance was at chance level for the control display, but dropped below chance for the equiluminant - luminant display. When subjects indicated just the direction of the luminant dots, judgments were not affected by equiluminant motion. Judgments for the equiluminant dots also were accurate, except for the conditions with 30° difference; these responses were biased by the luminant motion, indicating some form of motion capture. The interactive effects are discussed in terms of a directionally selective mechanism that combines equiluminant and luminant motion signals

    Development of an integrated heat pipe-thermal storage system for a solar receiver

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    The Organic Rankine Cycle (ORC) Solar Dynamic Power System (SDPS) is one of the candidates for Space Station prime power application. In the low Earth orbit of the Space Station approximately 34 minutes of the 94-minute orbital period is spent in eclipse with no solar energy input to the power system. For this period the SDPS will use thermal energy storage (TES) material to provide a constant power output. An integrated heat-pipe thermal storage receiver system is being developed as part of the ORC-SDPS solar receiver. This system incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain the TES canisters within the potassium vapor space with the toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the Earth orbit, solar energy is delivered to the heat pipe in the ORC-SDPS receiver cavity. The heat pipe transforms the non-uniform solar flux incident in the heat pipe surface within the receiver cavity to an essentially uniform flux at the potassium vapor condensation interface in the heat pipe. During solar insolation, part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the balance stored in the TES units is transferred by the potassium vapor to the toluene heater tube

    Non-linear rheology of active particle suspensions: Insights from an analytical approach

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    We consider active suspensions in the isotropic phase subjected to a shear flow. Using a set of extended hydrodynamic equations we derive a variety of {\em analytical} expressions for rheological quantities such as shear viscosity and normal stress differences. In agreement to full-blown numerical calculations and experiments we find a shear thickening or -thinning behaviour depending on whether the particles are contractile or extensile. Moreover, our analytical approach predicts that the normal stress differences can change their sign in contrast to passive suspensions.Comment: 11 pages, 10 figures, appear in PR

    Analysis, design, and experimental results for lightweight space heat receiver canisters, phase 1

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    Critical technology experiments have been performed on thermal energy storage modules in support of the Brayton Advanced Heat Receiver program. The modules are wedge-shaped canisters designed to minimize the mechanical stresses that occur during the phase change of the lithium fluoride phase change material. Nickel foam inserts were used in some of the canisters to provide thermal conductivity enhancement and to distribute the void volume. Two canisters, one with a nickel foam insert, and one without, were thermally cycled in various orientations in a fluidized bed furnace. The only measurable impact of the nickel foam was seen when the back and short sides of the canister were insulated to simulate operation in the advanced receiver design. In tests with insulation, the furnace to back side delta T was larger in the canister with the nickel foam insert, probably due to the radiant absorptivity of the nickel. However, the differences in the temperature profiles of the two canisters were small, and in many cases the profiles matched fairly well. Computed Tomography (CT) was successfully used to nondestructively demarcate void locations in the canisters. Finally, canister dimensional stability, which was measured throughout the thermal cycling test program with an inspection fixture was satisfactory with a maximum change of 0.635 mm (0.025 in.)

    The MLL-Menin Interaction is a Therapeutic Vulnerability in <em>NUP98</em>-rearranged AML

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    \ua9 2023 Wolters Kluwer Health. All rights reserved. Chromosomal translocations involving the NUP98 locus are among the most prevalent rearrangements in pediatric acute myeloid leukemia (AML). AML with NUP98 fusions is characterized by high expression of HOXA and MEIS1 genes and is associated with poor clinical outcome. NUP98 fusion proteins are recruited to their target genes by the mixed lineage leukemia (MLL) complex, which involves a direct interaction between MLL and Menin. Here, we show that therapeutic targeting of the Menin-MLL interaction inhibits the propagation of NUP98-rearrranged AML both ex vivo and in vivo. Treatment of primary AML cells with the Menin inhibitor revumenib (SNDX-5613) impairs proliferation and clonogenicity ex vivo in long-term coculture and drives myeloid differentiation. These phenotypic effects are associated with global gene expression changes in primary AML samples that involve the downregulation of many critical NUP98 fusion protein-target genes, such as MEIS1 and CDK6. In addition, Menin inhibition reduces the expression of both wild-type FLT3 and mutated FLT3-ITD, and in combination with FLT3 inhibitor, suppresses patient-derived NUP98-r AML cells in a synergistic manner. Revumenib treatment blocks leukemic engraftment and prevents leukemia-associated death of immunodeficient mice transplanted with NUP98::NSD1 FLT3-ITD-positive patient-derived AML cells. These results demonstrate that NUP98-rearranged AMLs are highly susceptible to inhibition of the MLL-Menin interaction and suggest the inclusion of AML patients harboring NUP98 fusions into the clinical evaluation of Menin inhibitors

    A window of opportunity? The relevance of the rotating European Union presidency in the public eye

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    The rotating EU presidency's relevance for EU politics has decreased since the introduction of a permanent council president. However, news salience and framing of the own government acting as the EU presidency can amplify publicity for EU affairs. We, therefore, evaluate the visibility and framing of the EU presidency in 12 Austrian newspapers for 2009-2019. We conduct an automated text analysis of 22 presidencies over 11 years, testing several hypotheses statistically, and qualify results via manually coded frames of the Austrian EU presidency in 2018. The results confirm the crucial importance of the domestication of EU politics, underscoring the potential of the presidency to serve as a window of opportunity for public debate. We discuss our findings with reference to the EU's democratic deficit

    Salvage Local Treatments After Focal Therapy for Prostate Cancer

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    CONTEXT: Whether focal therapy (FT) for prostate cancer (PC) jeopardizes outcomes from salvage treatments is a matter of debate still to be resolved. OBJECTIVE: To review the literature on oncological and functional outcomes and complications for available treatment options for recurrent or residual PC after primary FT. EVIDENCE ACQUISITION: We performed a nonsystematic search of PubMed for articles assessing relevant outcomes for salvage local treatment after FT failure using a manual search. When no evidence could be extracted for the FT domain, records dealing with recurrence after whole-gland ablation were considered. EVIDENCE SYNTHESIS: Four retrospective series assessed salvage treatments after FT failure evaluating cases of radical prostatectomy (RP) and repeat ablation (sample size from 12 to 22 patients). The quality of the studies was low, with a high risk of bias. Other options are radiation therapy (RT) and whole-gland or focal repeat ablations, although these have only been described after whole-gland ablation. With some exceptions, including sexual function for RP, overall complications and oncological and functional outcomes do seem to be acceptable and are not much worse than those in the primary setting. Important limitations include the low level of the evidence and the absence of standardized criteria for FT, salvage treatment, and FT failure. CONCLUSIONS: Current evidence shows acceptable outcomes for post-FT salvage options, although this is based on retrospective data. While it seems that FT has a minimal impact on salvage treatment results, prospective controlled studies are needed to confirm these preliminary data. PATIENT SUMMARY: We performed a literature search to determine the treatment options available for prostate cancer after failure of focal therapy and their outcomes. Options include radical prostatectomy, repeat whole-gland ablation, focal ablation, and radiotherapy. Overall cancer control, impacts on urinary and sexual function, and complications seem slightly worse but not markedly different compared to primary treatments, but high-quality studies are awaited to confirm these findings

    Structure and Strength of Dislocation Junctions: An Atomic Level Analysis

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    The quasicontinuum method is used to simulate three-dimensional Lomer-Cottrell junctions both in the absence and in the presence of an applied stress. The simulations show that this type of junction is destroyed by an unzipping mechanism in which the dislocations that form the junction are gradually pulled apart along the junction segment. The calculated critical stress needed for breaking the junction is comparable to that predicted by line tension models. The simulations also demonstrate a strong influence of the initial dislocation line directions on the breaking mechanism, an effect that is neglected in the macroscopic treatment of the hardening effect of junctions.Comment: 4 pages, 3 figure

    Estudio de distribución de temperatura en un motor mono-cilíndrico de combustión interna aplicando el método de elementos finitos

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    Resulta de vital importancia tener conocimiento de las temperaturas existentes en puntos clave de la cámara de combustión, para de este modo, poder predecir las condiciones en que se lleva a cabo el ciclo termodinámico dentro del cilindro. El conocimiento de estas temperaturas es vital para optimizar el circuito de refrigeración, componente fundamental para un correcto desempeño del motor. En el presente trabajo se propone un método experimental/numérico para la obtención de las variables mencionadas anteriormente, mediante el cual no es necesario afectar la integridad de la cámara de combustión, lo que posibilita una primera determinación de las temperaturas alcanzadas en piezas claves del mismo de difícil acceso (Ej.: válvulas, asientos de válvulas, aristas de la cámara de combustión, etc.). Dicho procedimiento consiste en la medición de parámetros tales como temperatura sobre tapa de cilindro, velocidad de aire de refrigeración consumo de combustible, y condiciones ambientales sobre un motor mono-cilíndrico en funcionamiento regular y una simulación por elementos finitos de la distribución de temperaturas. Los resultados obtenidos por medio del método de elementos finitos corresponden con los registrados a través de las mediciones realizadas como también con la bibliografía consultada, validando así el modelo numérico y convirtiéndolo en una alternativa económica y fiable a la hora de evaluar futuras modificaciones en el diseño del motor
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