717 research outputs found

    Does \u3cem\u3eState National Bank of Big Spring v. Geithner\u3c/em\u3e Stand a Fighting Chance?

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    Two years after the start of the 2008 financial crisis and during one of the worst economic recessions since the Great Depression, Congress passed a law designed to insure a financial crisis of the same magnitude would not occur again, and if it did, it would not have the same wide-reaching effects the 2008 crisis had. The Dodd-Frank Wall Street Reform and Consumer Protection Act sought to, among other things, end “too big to fail,” consolidate the consumer protection agencies, and provide for the orderly liquidation of defaulting systematically important companies. State National Bank of Big Spring v. Geithner, a case filed in D.C. Federal District Court, challenges the constitutionality of the Act’s provisions. This article reviews a subset of the claims raised in that case and argues that certain provisions of the Act are constitutional while others violate the separate of powers inherent in our Constitution

    Does \u3cem\u3eState National Bank of Big Spring v. Geithner\u3c/em\u3e Stand a Fighting Chance?

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    Two years after the start of the 2008 financial crisis and during one of the worst economic recessions since the Great Depression, Congress passed a law designed to insure a financial crisis of the same magnitude would not occur again, and if it did, it would not have the same wide-reaching effects the 2008 crisis had. The Dodd-Frank Wall Street Reform and Consumer Protection Act sought to, among other things, end “too big to fail,” consolidate the consumer protection agencies, and provide for the orderly liquidation of defaulting systematically important companies. State National Bank of Big Spring v. Geithner, a case filed in D.C. Federal District Court, challenges the constitutionality of the Act’s provisions. This article reviews a subset of the claims raised in that case and argues that certain provisions of the Act are constitutional while others violate the separate of powers inherent in our Constitution

    Effects of non-steroidal antiinflammatory drugs and dexamethasone on the activity and expression of matrix metalloproteinase-1, matrix metalloproteinase-3 and tissue inhibitor of metalloproteinases-1 by bovine articular chondrocytes

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    AbstractObjective To determine the in-vitro effects of several non-steroidal antiinflammatory drugs and the glucocorticoid dexamethasone on the IL-1 altered expression and activity of MMP-1, MMP-3 and TIMP-1 by bovine articular chondrocytes.Design Bovine chondrocytes were cultured in alginate gel beads. Cells were treated with IL-1α in the presence of vehicle or drugs at various concentrations. After 48h mRNA expression of MMP-1, MMP-3, and of the tissue inhibitor of metalloproteinases (TIMP-1) was analysed by RT-PCR-ELISA. The protein synthesis of TIMP-1 and MMP-3 was determined by immunoprecipitation. The activity of enzymes and inhibitors was measured by functional assays.Results IL-1 increased the expression and activity of MMPs. In contrast, TIMP activity remained unchanged although TIMP-1 expression was down-regulated. All tested NSAIDs and dexamethasone inhibited collagenase activity induced by IL-1. Transcript levels of MMP-1, however, were only reduced by indomethacin, meloxicam, naproxen and dexamethasone. Proteoglycanase activity was only reduced by indomethacin, meloxicam and dexamethasone. These effects were pre-translational as confirmed by immunoprecipitation. The IL-1 decreased expression of TIMP-1 was further reduced by dexamethasone, which resulted in a significant loss of TIMP activity. No effects on TIMP activity or TIMP-1 biosynthesis were observed after treatment of chondrocytes with NSAIDs.Conclusion Our studies clearly demonstrate that marked differences exist between individual NSAIDs with respect to their ability to modulate the imbalance between proteases and inhibitors during OA and RA, suggesting that the respective modes of action are independent of the inhibition of cyclooxygenases. Due to their co-regulation of MMPs and TIMP(s) glucocorticoids should be carefully studied for their overall effect on ECM proteolysis

    Power distribution unit (Array E)

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    his specification establishes the requirements for performance, design, test, and qualification of the component identified ast he power distribution unit (PDU) of the central station subsystem (specification AL 210 100) for the Apollo Lunar Surface Experiments Package (ALSEP) Array E.prepared by D. J. Steinmeyer

    Reconstructing Gaussian bipartite states with a single polarization-sensitive homodyne detector

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    We present a novel method to fully estimate Gaussian bipartite polarization states using only a single homodyne detector. Our approach is based on [Phys. Rev. Lett. 102, 020502 (2009)], but circumvents additional optics, and thereby losses, in the signal path. We provide an intuitive explanation of our scheme without needing to define auxiliary modes. With six independent measurements, we fully reconstruct the state’s covariance matrix. We validate our method by comparing it to a conventional dual-homodyne measurement scheme

    Pulse confinement in optical fibers with random dispersion

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    Short range correlated uniform noise in the dispersion coefficient, inherent in many types of optical fibers, broadens and eventually destroys all initially ultra-short pulses. However, under the constraint that the integral of the random component of the dispersion coefficient is set to zero, or pinned, periodically or quasi-periodically along the fiber, the nature of the pulse propagation changes dramatically. For the case that randomness is added to constant positive dispersion, the pinning restriction significantly reduces pulse broadening. If the randomness is added to piecewise constant periodic dispersion, the pinning may even provide probability distributions of pulse parameters that are numerically indistinguishable from the statistically steady case. The pinning method can be used to both manufacture better fibers and upgrade existing fiber links.Comment: 4 pages, 2 figure

    Carrier-envelope-offset dynamics and stabilization of femtosecond pulses

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    Abstract. : We analyze and stabilize fluctuations of the relative phase between the carrier and the envelope of a mode-locked laser. Mechanisms generating fluctuations of the carrier-envelope-offset (CEO) phase are experimentally identified in lasers with and without prisms for dispersion compensation. One mechanism is amplitude-to-phase coupling via self-steepening. This mechanism translates power changes into variations of the CEO phase. A similar but much stronger effect is caused by beam-pointing variations in lasers with intracavity prisms. Both mechanisms convert power noise of the laser into phase noise and can be used to externally control or stabilize the CEO frequency by adjusting the pump power. Our measurements are well explained by a theoretical model. This investigation allowed us to obtain an unsurpassed stabilization of the CEO phase to 0.02rad rms for a frequency range from 0.01Hz to 10kHz. We extend the discussion to pulse-amplification schemes and show that beam-pointing variations are also expected to have a strong influence on the CEO phase of amplified pulses. We discuss methods to reduce or avoid CEO noise by suitable design of the dispersion-compensation scheme, both in oscillators and in amplifier

    Frequency-Dependent Squeezing from a Detuned Squeezer

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    Cascaded self-compression of femtosecond pulses in filaments

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    Highly nonlinear wave propagation scenarios hold the potential to serve for energy concentration or pulse duration reduction of the input wave form, provided that a small range of input parameters be maintained. In particular when phenomena like rogue-wave formation or few-cycle optical pulses generation come into play, it becomes increasingly difficult to maintain control of the waveforms. Here we suggest an alternative approach towards the control of waveforms in a highly nonlinear system. Cascading pulse self-compression cycles at reduced nonlinearity limits the increase of input parameter sensitivity while still enabling an enhanced compression effect. This cascaded method is illustrated by experiments and in numerical simulations of the Nonlinear Schrödinger Equation, simulating the propagation of short optical pulses in a self-generated plasma

    Sub-6-fs blue pulses generated by quasi-phase-matching second-harmonic generation pulse compression

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    Abstract. : We demonstrate a novel scalable and engineerable approach for the frequency-doubling of ultrashort pulses. Our technique is based on quasi-phase-matching and simultaneously provides tailored dispersion and nonlinear frequency conversion of few-cycle optical pulses. The method makes use of the spatial localization of the conversion process and the group velocity mismatch in a chirped grating structure. The total group delay of the nonlinear device can be designed to generate nearly arbitrarily chirped second-harmonic pulses from positively or negatively chirped input pulses. In particular, compressed second-harmonic pulses can be obtained. A brief summary of the underlying theory is presented, followed by a detailed discussion of our experimental results. We experimentally demonstrate quasi-phase-matching pulse compression in the sub-10-fs regime by generating few-cycle pulses in the blue to near-ultraviolet spectral range. Using this new frequency conversion technique, we generate sub-6-fs pulses centered at 405nm by second-harmonic generation from a 8.6fs Ti:sapphire laser pulse. The generated spectrum spans a bandwidth of 220THz. To our knowledge, these are the shortest pulses ever obtained by second-harmonic generatio
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