cssi/SciSciGPT-SciSciNet huggingface dataset:
Monodromy and local-global compatibility for l = p

We strengthen the compatibility between local and global Langlands correspondences for GLn when n is even and l=p. Let L be a CM field and Π a cuspidal automorphic representation of GLn(AL) which is conjugate self-dual and regular algebraic. In this case, there is an l-adic Galois representation associated to Π, which is known to be compatible with local Langlands in almost all cases when l=p by recent work of Barnet-Lamb, Gee, Geraghty and Taylor. The compatibility was proved only up to semisimplification unless Π has Shin-regular weight. We extend the compatibility to Frobenius semisimplification in all cases by identifying the monodromy operator on the global side. To achieve this, we derive a generalization of Mokrane’s weight spectral sequence for log crystalline cohomology.
The Dynamics of the Envelope Surrounding the Protostar HH 211 mm

We present a study of the structure and dynamics of the dense gas surrounding the HH 211 mm source, using Very Large Array (VLA) observations of the ammonia (1,1) and (2,2) inversion transitions. We find that the envelope around this Class 0 source has an elongated geometry, extending about 104 AU in the direction perpendicular to the well-known HH 211 jet, and exhibits a velocity distribution consistent with rotation along the major axis. Our VLA observations indicate that the envelope is mostly in virial equilibrium. However, comparing our data with results from previous studies, it appears that the gas within approximately 0.005 pc of the central protostar is undergoing dynamical collapse. The size of this collapsing radius may constrain the amount of mass that can eventually infall into the forming star. We also find that the envelope is mostly internally heated, most probably by radiation from the central protostar. In addition, we detect evidence of outflow-envelope interaction in the ammonia data. These include a velocity gradient in the dense gas along the outflow axis and significant line broadening that is spatially correlated with the jet and could be the result of outflow-induced turbulence in the envelope.
Power law inflation with electromagnetism

Abstract We generalize Ringstrom’s global future causal stability results (Ringstrom 2009) [11] for certain expanding cosmological solutions of the Einstein-scalar field equations to solutions of the Einstein–Maxwell-scalar field system. In particular, after noting that the power law inflationary spacetimes ( M n + 1 , g ˆ , ϕ ˆ ) considered by Ringstrom (2009) in [11] are solutions of the Einstein–Maxwell-scalar field system (with exponential potential) as well as of the Einstein-scalar field system (with the same exponential potential), we consider (nonlinear) perturbations of initial data sets of these spacetimes which include electromagnetic perturbations as well as gravitational and scalar perturbations. We show that if (as in Ringstrom (2009) [11] ) we focus on pairs of relatively scaled open sets U R 0 ⊂ U 4 R 0 on an initial slice of ( M n + 1 , g ˆ ) , and if we choose a set of perturbed data which on U 4 R 0 is sufficiently close to that of ( M n + 1 , g ˆ , ϕ ˆ , A ˆ = 0 ) , then in the maximal globally hyperbolic spacetime development ( M n + 1 , g , ϕ , A ) of this data via the Einstein–Maxwell-scalar field equations, all causal geodesics emanating from U R 0 are future complete (just as in ( M n + 1 , g ˆ ) ). We also verify that, in a certain sense, the future asymptotic behavior of the fields in the spacetime developments of the perturbed data sets does not differ significantly from the future asymptotic behavior of ( M n + 1 , g ˆ , ϕ ˆ , A ˆ = 0 ) .
Cosmography and Power Spectrum Estimation: a Unified Approach

We present a unified approach to the problems of reconstruction of large-scale structure distribution in the universe and determination of the underlying power spectrum. These have often been treated as two separate problems, and different analysis techniques have been developed for both. We show that there exists a simple relation between the optimal solutions to the two problems, allowing us to solve for both within the same formalism. This allows one to apply computational techniques developed for one method to the other, which often leads to a significant reduction in the computational time. It also provides a self-consistent treatment of linear reconstruction by first computing the power spectrum from the data themselves.
Confronting Models of Dwarf Galaxy Quenching with Observations of the Local Group

A number of mechanisms have been proposed to connect star-forming dwarf irregular galaxies with the formation of non-star-forming dwarf spheroidal galaxies (dSphs), but distinguishing between these mechanisms has been difficult. We use the Via Lactea (VL) dark matter only cosmological simulations to test two well-motivated simple hypotheses—transformation of irregulars into dSphs by tidal stirring and ram pressure stripping following a close passage to the host galaxy, and transformation via mergers between dwarfs—and predict the radial distribution and inferred formation times of the resulting dSphs. We compare this to the observed distribution in the Local Group and show that (1) the observed dSph distribution far from the Galaxy or M31 can be matched by the VL halos that have passed near the host galaxy at least once, though significant halo-to-halo scatter exists, (2) models that require two or more pericenter passages for dSph-formation cannot account for the dSphs beyond 500 kpc such as Cetus and Tucana, and (3) mergers predict a flat radial distribution of dSphs and cannot account for the high dSph fraction near the Galaxy, but are not ruled out at large distances. The models also suggest that for dSphs found today beyond 500 kpc, mergers tend to occur significantly earlier than dwarf-host encounters, thus leading to a potentially observable difference in stellar populations. We argue that tidal interactions are sufficient to reproduce the observed distribution of dSphs if and only if a single pericenter passage is sufficient to form a dSph.
Revealing structure-function relationships in functional flow networks via persistent homology

This work showcases an approach to characterizing structure-function relationships in complex networks in the context of flow networks tuned to perform specific functions. The authors find that the response of such networks encodes hidden topological features---sectors of uniform pressure---that are not apparent in the underlying network architectures, providing a universal topological description for all networks that perform these types of functions.
The dirichlet-conormal problem with homogeneous and inhomogeneous boundary conditions

We consider the mixed Dirichlet-conormal problem on irregular domains in Rd. Two types of regularity results will be discussed: the W1,p regularity and a non-tangential maximal function estimate. T...
Thermal transport in a noncommutative hydrodynamics

We find the hydrodynamic equations of a system of particles constrained to be in the lowest Landau level. We interpret the hydrodynamic theory as a Hamiltonian system with the Poisson brackets between the hydrodynamic variables determined from the noncommutativity of space. We argue that the most general hydrodynamic theory can be obtained from this Hamiltonian system by allowing the Righi-Leduc coefficient to be an arbitrary function of thermodynamic variables. We compute the Righi-Leduc coefficient at high temperatures and show that it satisfies the requirements of particle-hole symmetry, which we outline.
On the Timescale for Star Formation in Galaxies

The timescale for star formation, a measure of how quickly neutral gas is being converted to stars, is considerably longer than typical dynamical timescales associated with a galactic disk. For purposes of modeling galaxy evolution, however, it would be extremely attractive if the star formation timescale was proportional to an easily derived dynamical timescale. We compare estimates of the star formation timescale within nearby galaxies, based on the work of Leroy et al. and existing BIMA Survey of Nearby Galaxies CO data, with three simple forms of the dynamical time: the orbital time; the free-fall time at the midplane density; and the disk Jeans time (the growth time for gravitational instabilities in a disk). When taking into account the gravity of the stellar disk in an approximate way, all three timescales show correlations with the star formation timescale, though none of the correlations can be accurately described as linear. Systematic errors in estimating appropriate gas masses and the stellar velocity dispersion may obscure an underlying correlation, but we focus instead on a model where the timescale for H2 formation from H I is decoupled from the timescale for star formation from H2. The Jeans time correlates well with the first of these timescales, but the relationship is still non-linear and requires a characteristic giant molecular cloud lifetime that increases toward galaxy centers.
News on the Nuclear Structure of Neutron-rich Nuclei at and beyond N = 28

The nuclear potential and resulting shell structure are well established for the valley of stability, however, dramatic modifications to the familiar ordering of single-particle orbitals in rare isotopes with a large imbalance of proton and neutron numbers have been found: new shell gaps emerge and conventional magic numbers are no longer valid. This article outlines some of the recent in-beam gamma-ray spectroscopy measurements at NSCL aimed at shedding light on the evolution of nuclear structure around neutron number N = 28 in neutron-rich Ar and S isotopes.
Nonequilibrium relaxation and scaling properties of the two-dimensional Coulomb glass in the aging regime

We employ Monte Carlo simulations to investigate the two-time density autocorrelation function for the two-dimensional Coulomb glass. We find that the nonequilibrium relaxation properties of this highly correlated disordered system can be described by a full-aging scaling ansatz. The scaling exponents are nonuniversal, and depend on temperature and charge density.
Exothermic double-disk dark matter

If a subdominant component of dark matter (DM) interacts via long-range dark force carriers it may cool and collapse to form complex structures within the Milky Way galaxy, such as a rotating dark disk. This scenario was proposed recently and termed ``Double-Disk Dark Matter'' (DDDM). In this paper we consider the possibility that DDDM remains in a cosmologically long-lived excited state and can scatter exothermically on nuclei (ExoDDDM). We investigate the current status of ExoDDDM direct detection and find that ExoDDDM can readily explain the recently announced ~ 3σ excess observed at CDMS-Si, with almost all of the 90% best-fit parameter space in complete consistency with limits from other experiments, including XENON10 and XENON100. In the absence of isospin-dependent couplings, this consistency requires light DM with mass typically in the 5-15 GeV range. The hypothesis of ExoDDDM can be tested in direct detection experiments through its peaked recoil spectra, reduced annual modulation amplitude, and, in some cases, its novel time-dependence. We also discuss future direct detection prospects and additional indirect constraints from colliders and solar capture of ExoDDDM. As theoretical proof-of-principle, we combine the features of exothermic DM models and DDDM models to construct a complete model of ExoDDDM, exhibiting all the required properties.
Dynamics of antimembranes in the maximally supersymmetric eleven-dimensional pp wave

We study a spherical antimembrane in the eleven dimensional pp wave. In this background, a single antimembrane breaks all the supersymmetries because its dipole is misaligned with the background flux. Using the BMN matrix theory we compute the one-loop potential for the antimembrane. Then we put the antimembrane in the field produced by a source spherical membrane and compute the velocity-dependent part of the interaction between them on both the supergravity side and the BMN matrix theory side. Despite the aforementioned nonsupersymmetry of the antimembrane, it is found that the results on the two sides completely agree.
D-optimal designs via a cocktail algorithm

A fast new algorithm is proposed for numerical computation of (approximate) D-optimal designs. This cocktail algorithm extends the well-known vertex direction method (VDM; Fedorov in Theory of Optimal Experiments, 1972) and the multiplicative algorithm (Silvey et al. in Commun. Stat. Theory Methods 14:1379---1389, 1978), and shares their simplicity and monotonic convergence properties. Numerical examples show that the cocktail algorithm can lead to dramatically improved speed, sometimes by orders of magnitude, relative to either the multiplicative algorithm or the vertex exchange method (a variant of VDM). Key to the improved speed is a new nearest neighbor exchange strategy, which acts locally and complements the global effect of the multiplicative algorithm. Possible extensions to related problems such as nonparametric maximum likelihood estimation are mentioned.
Stochastic Discontinuous Galerkin Methods (SDGM) based on fluctuation-dissipation balance

Author(s): Pazner, W; Trask, N; Atzberger, PJ | Abstract: We introduce a general framework for approximating parabolic Stochastic Partial Differential Equations (SPDEs) based on fluctuation-dissipation balance. Using this approach we formulate Stochastic Discontinuous Galerkin Methods (SDGM). We show how methods with linear-time computational complexity can be developed for handling domains with general geometry and generating stochastic terms handling both Dirichlet and Neumann boundary conditions. We demonstrate our approach on example systems and contrast with alternative approaches using direct stochastic discretizations based on random fluxes. We show how our Fluctuation-Dissipation Discretizations (FDD) framework allows for compensating for differences in dissipative properties of discrete numerical operators relative to their continuum counter-parts. This allows us to handle general heterogeneous discretizations capturing accurately statistical relations. Our FDD framework provides a general approach for formulating SDGM discretizations and other numerical methods for robust approximation of stochastic differential equations.
Spekkens’ Toy Model, Finite Field Quantum Mechanics, and the Role of Linearity

We map Spekkens' toy model to a quantum mechanics defined over the finite field . This allows us to define arbitrary linear combinations of the epistemic states in the model. For Spekkens' elementary system with only 22 = 4 ontic states, the mapping is exact and the two models agree completely. However, for a pair of elementary systems there exist interesting differences between the entangled states of the two models.
Dead Zone in the Polar-cap Accelerator of Pulsars

We study plasma flows above pulsar polar caps using time-dependent simulations of plasma particles in the self-consistent electric field. The flow behavior is controlled by the dimensionless parameter α = j/cρGJ, where j is the electric current density and ρGJ is the Goldreich-Julian charge density. The region of the polar cap where 0 0). In the latter case, we consider the possibility of a mixed flow consisting of different ion species, and observe the development of two-stream instability. The dead zone at the polar cap is essential for the development of an outer gap near the null surface ρGJ = 0.
Should One Use the Ray-by-Ray Approximation in Core-collapse Supernova Simulations?

We perform the first self-consistent, time-dependent, multi-group calculations in two dimensions (2D) to address the consequences of using the ray-by-ray+ transport simplification in core-collapse supernova simulations. Such a dimensional reduction is employed by many researchers to facilitate their resource-intensive calculations. Our new code (F{\sc{ornax}}) implements multi-D transport, and can, by zeroing out transverse flux terms, emulate the ray-by-ray+ scheme. Using the same microphysics, initial models, resolution, and code, we compare the results of simulating 12-, 15-, 20-, and 25-M$_{\odot}$ progenitor models using these two transport methods. Our findings call into question the wisdom of the pervasive use of the ray-by-ray+ approach. Employing it leads to maximum post-bounce/pre-explosion shock radii that are almost universally larger by tens of kilometers than those derived using the more accurate scheme, typically leaving the post-bounce matter less bound and artificially more "explodable." In fact, for our 25-M$_{\odot}$ progenitor, the ray-by-ray+ model explodes, while the corresponding multi-D transport model does not. Therefore, in two dimensions the combination of ray-by-ray+ with the axial sloshing hydrodynamics that is a feature of 2D supernova dynamics can result in quantitatively, and perhaps qualitatively, incorrect results.
REDUCING THE DIMENSIONALITY OF DATA: LOCALLY LINEAR EMBEDDING OF SLOAN GALAXY SPECTRA

We introduce locally linear embedding (LLE) to the astronomical community as a new classification technique, using Sloan Digital Sky Survey spectra as an example data set. LLE is a nonlinear dimensionality reduction technique that has been studied in the context of computer perception. We compare the performance of LLE to well-known spectral classification techniques, e.g., principal component analysis and line-ratio diagnostics. We find that LLE combines the strengths of both methods in a single, coherent technique, and leads to improved classification of emission-line spectra at a relatively small computational cost. We also present a data subsampling technique that preserves local information content, and proves effective for creating small, efficient training samples from large, high-dimensional data sets. Software used in this LLE-based classification is made available.
Ab Initio Study of Ground-state CS Photodissociation via Highly Excited Electronic States

Author(s): Xu, Z; Luo, N; Federman, SR; Jackson, WM; Ng, CY; Wang, LP; Crabtree, KN | Abstract: Photodissociation by ultraviolet radiation is the key destruction pathway for CS in photon-dominated regions, such as diffuse clouds. However, the large uncertainties of photodissociation cross sections and rates of CS, resulting from a lack of both laboratory experiments and theoretical calculations, limit the accuracy of calculated abundances of S-bearing molecules by modern astrochemical models. Here we show a detailed ab initio study of CS photodissociation. Accurate potential energy curves of CS electronic states were obtained by choosing an active space CAS(8,10) in MRCI+Q/aug-cc-pV(5+d)Z calculation with additional diffuse functions, with a focus on the B and C 1Σ+ states. Cross sections for both direct photodissociation and predissociation from the vibronic ground state were calculated by applying the coupled-channel method. We found that the C - X (0 - 0) transition has extremely strong absorption due to a large transition dipole moment in the Franck-Condon region, and the upper state is resonant with several triplet states via spin-orbit couplings, resulting in predissociation to the main atomic products C (3 P) and S (1 D). Our new calculations show that the photodissociation rate under the standard interstellar radiation field is 2.9-10-9 s-1, with a 57% contribution from C - X (0 - 0) transition. This value is larger than that adopted by the Leiden photodissociation and photoionization database by a factor of 3.0. Our accurate ab initio calculations will allow more secure determination of S-bearing molecules in astrochemical models.
High-throughput screening of small-molecule adsorption in MOF

Using high-throughput screening coupled with state-of-the-art van der Waals density functional theory, we investigate the adsorption properties of four important molecules, H2, CO2, CH4, and H2O in MOF-74- with = Be, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Ru, Rh, Pd, La, W, Os, Ir, and Pt. We show that high-throughput techniques can aid in speeding up the development and refinement of effective materials for hydrogen storage, carbon capture, and gas separation. The exploration of the configurational adsorption space allows us to extract crucial information concerning, for example, the competition of water with CO2 for the adsorption binding sites. We find that only a few noble metals—Rh, Pd, Os, Ir, and Pt—favor the adsorption of CO2 and hence are potential candidates for effective carbon-capture materials. Our findings further reveal significant differences in the binding characteristics of H2, CO2, CH4, and H2O within the MOF structure, indicating that molecular blends can be successfully separated by these nano-porous materials.
The Close Companion Mass-ratio Distribution of Intermediate-mass Stars

Binary stars and higher-order multiple systems are a ubiquitous outcome of star formation, especially as the system mass increases. The companion mass-ratio distribution is a unique probe into the conditions of the collapsing cloud core and circumstellar disk(s) of the binary fragments. Inside the disks from the two forming stars can interact, and additionally companions can form directly through disk fragmentation. We should, therefore, expect the mass-ratio distribution of close companions ( AU) to differ from that of wide companions. This prediction is difficult to test using traditional methods, in particular, with intermediate-mass primary stars, for a variety of observational reasons. We present the results of a survey searching for companions to A- and B-type stars using the direct spectral detection method, which is sensitive to late-type companions within of the primary and which has no inner working angle. We estimate the temperatures and surface gravity of most of the 341 sample stars and derive their masses and ages. We additionally estimate the temperatures and masses of the 64 companions we find, 23 of which are new detections. We find that the mass-ratio distribution for our sample has a maximum near . Our mass-ratio distribution has a very different form than in previous works, where it is usually well-described by a power law, and indicates that close companions to intermediate-mass stars experience significantly different accretion histories or formation mechanisms than wide companions.
The frequency-dependent effect of electrical fields on the mobility of intracellular vesicles in astrocytes.

Slow-wave sleep, defined by low frequency (<4 Hz) electrical brain activity, is a basic brain function affecting metabolite clearance and memory consolidation. The origin of low-frequency activity is related to cortical up and down states, but the underlying cellular mechanism of how low-frequency activities affect metabolite clearance and memory consolidation has remained elusive. We applied electrical stimulation with voltages comparable to in vivo sleep recordings over a range of frequencies to cultured glial astrocytes while monitored the trafficking of GFP-tagged intracellular vesicles using total internal reflection fluorescence microscopy (TIRFM). We found that during low frequency (2 Hz) electrical stimulation the mobility of intracellular vesicle increased more than 20%, but remained unchanged under intermediate (20 Hz) or higher (200 Hz) frequency stimulation. We demonstrated a frequency-dependent effect of electrical stimulation on the mobility of astrocytic intracellular vesicles. We suggest a novel mechanism of brain modulation that electrical signals in the lower range frequencies embedded in brainwaves modulate the functionality of astrocytes for brain homeostasis and memory consolidation. The finding suggests a physiological mechanism whereby endogenous low-frequency brain oscillations enhance astrocytic function that may underlie some of the benefits of slow-wave sleep and highlights possible medical device approach for treating neurological diseases.
A review on machine learning for neutrino experiments

Neutrino experiments study the least understood of the Standard Model particles by observing their direct interactions with matter or searching for ultra-rare signals. The study of neutrinos typica...
Cloud Computing in Developing Economies

The developing world must exploit the opportunities afforded by cloud computing while minimizing the associated risks to allow access to advanced IT infrastructure, data centers, and applications and protect sensitive information.
Future Smart Connected Communities to Fight COVID-19 Outbreak

Abstract Internet of Things (IoT) has grown rapidly in the last decade and continues to develop in terms of dimension and complexity, offering a wide range of devices to support a diverse set of applications. With ubiquitous Internet, connected sensors and actuators, networking and communication technology along with artificial intelligence (AI), smart cyber-physical systems (CPS) provide services rendering assistance and convenience to humans in their daily lives. However, the recent outbreak of COVID-19 (also known as coronavirus) pandemic has exposed and highlighted the limitations of contemporary technological deployments especially to contain the widespread of this disease. IoT and smart connected technologies together with data-driven applications can play a crucial role not only in the prevention, mitigation, or continuous remote monitoring of patients, but also enable prompt enforcement of guidelines, rules, and administrative orders to contain such future outbreaks. In this paper, we envision an IoT and data-supported connected ecosystem designed for intelligent monitoring, pro-active prevention and control, and mitigation of COVID-19 and similar epidemics. We propose a gamut of synergistic applications and technology systems for various smart infrastructures including E-Health, smart home, supply chain management, transportation, and city, which will work in convergence to develop ‘pandemic-proof’ future smart communities. We also present a generalized cloud-enabled IoT implementation framework along with scientific solutions, which can be adapted and extended to deploy smart connected ecosystem scenarios using widely used Amazon Web Services (AWS) cloud infrastructures. In addition, we also implement an E-Health RPM use case scenario to demonstrate the need and practicality for smart connected communities. Finally, we highlight challenges and research directions that need thoughtful consideration and across the board cooperation among stakeholders to build resilient communities against future pandemics.
Wanna Make Your TCP Scheme Great for Cellular Networks? Let Machines Do It for You!

Can we instead of designing yet another new TCP algorithm, design a TCP plug-in that can enable machines to automatically boost the performance of the existing/future TCP designs in cellular networks? We answer this question by introducing DeepCC. DeepCC leverages advanced deep reinforcement learning (DRL) techniques to let machines automatically learn how to steer throughput-oriented TCP algorithms toward achieving applications’ desired delays in a highly dynamic network such as the cellular network. We used DeepCC plug-in to boost the performance of various old and new TCP schemes including TCP Cubic, Google’s BBR, TCP Westwood, and TCP Illinois in cellular networks. Through both extensive trace-based evaluations and real-world experiments, we show that not only DeepCC can significantly improve the performance of TCP schemes, but also after accompanied by DeepCC, these schemes can outperform state-of-the-art TCP protocols including new clean-slate machine learning-based designs and the ones designed solely for cellular networks.
Trisections of $4$-manifolds via Lefschetz fibrations

We develop a technique for gluing relative trisection diagrams of $4$-manifolds with nonempty connected boundary to obtain trisection diagrams for closed $4$-manifolds. As an application, we describe a trisection of any closed $4$-manifold which admits a Lefschetz fibration over $S^2$ equipped with a section of square $-1$, by an explicit diagram determined by the vanishing cycles of the Lefschetz fibration. In particular, we obtain a trisection diagram for some simply connected minimal complex surface of general type. As a consequence, we obtain explicit trisection diagrams for a pair of closed $4$-manifolds which are homeomorphic but not diffeomorphic. Moreover, we describe a trisection for any oriented $S^2$-bundle over any closed surface and in particular we draw the corresponding diagrams for $T^2 \times S^2$ and $T^2 \tilde{\times} S^2$ using our gluing technique. Furthermore, we provide an alternate proof of a recent result of Gay and Kirby which says that every closed $4$-manifold admits a trisection. The key feature of our proof is that Cerf theory takes a back seat to contact geometry.
An Optimal Multistage Stochastic Gradient Method for Minimax Problems

In this paper, we study the minimax optimization problem in the smooth and strongly convex-strongly concave setting when we have access to noisy estimates of gradients. In particular, we first analyze the stochastic Gradient Descent Ascent (GDA) method with constant stepsize, and show that it converges to a neighborhood of the solution of the minimax problem. We further provide tight bounds on the convergence rate and the size of this neighborhood. Next, we propose a multistage variant of stochastic GDA (M-GDA) that runs in multiple stages with a particular learning rate decay schedule and converges to the exact solution of the minimax problem. We show M-GDA achieves the lower bounds in terms of noise dependence without any assumptions on the knowledge of noise characteristics. We also show that M-GDA obtains a linear decay rate with respect to the error’s dependence on the initial error, although the dependence on condition number is suboptimal. In order to improve this dependence, we apply the multistage machinery to the stochastic Optimistic Gradient Descent Ascent (OGDA) algorithm and propose the M-OGDA algorithm which also achieves the optimal linear decay rate with respect to the initial error. To the best of our knowledge, this method is the first to simultaneously achieve the best dependence on noise characteristic as well as the initial error and condition number.
Insights into genome recoding from the mechanism of a classic +1-frameshifting tRNA.

While genome recoding using quadruplet codons to incorporate non-proteinogenic amino acids is attractive for biotechnology and bioengineering purposes, the mechanism through which such codons are translated is poorly understood. Here we investigate translation of quadruplet codons by a +1-frameshifting tRNA, SufB2, that contains an extra nucleotide in its anticodon loop. Natural post-transcriptional modification of SufB2 in cells prevents it from frameshifting using a quadruplet-pairing mechanism such that it preferentially employs a triplet-slippage mechanism. We show that SufB2 uses triplet anticodon-codon pairing in the 0-frame to initially decode the quadruplet codon, but subsequently shifts to the +1-frame during tRNA-mRNA translocation. SufB2 frameshifting involves perturbation of an essential ribosome conformational change that facilitates tRNA-mRNA movements at a late stage of the translocation reaction. Our results provide a molecular mechanism for SufB2-induced +1 frameshifting and suggest that engineering of a specific ribosome conformational change can improve the efficiency of genome recoding. Genome recoding with quadruplet codons requires a +1-frameshift-suppressor tRNA able to insert an amino acid at quadruplet codons of interest. Here the authors identify the mechanisms resulting in +1 frameshifting and the steps of the elongation cycle in which it occurs.
Accommodating Outness: Hurley, Free Speech, and Gay and Lesbian Equality

In this article I explore two important questions raised by the Hurley v. Irish-American Gay, Lesbian and Bisexual Group of Boston decision. First, although the Supreme Court did not analyze the case under the Roberts framework, it suggested at the conclusion of the opinion that the case would have the same outcome under that test. The Court's dictum concerning the Roberts trilogy thus raises the question whether Hurley indicates that the Court might disturb the Roberts doctrine if presented with the opportunity. Second, the Hurley Court, in rejecting GLIB's claim, found that the parade organizers were not attempting to exclude gay and lesbian participants as such, but rather merely did not want the plaintiff to march in the parade as an organized unit with banners and other accouterments of parade participation. This finding contradicts the state court's finding of fact that the exclusion of the unit amounted to invidious discrimination on the basis of sexual orientation. The state court's rulings are plausible given the importance of outness and open declarations of sexual orientation in the struggle for gay and lesbian equality and in the construction of sexual identity. Because outness is intertwined with sexual identity, defendant's refusal to allow GLIB to march openly in the parade constituted an attempt to silence -- or closet -- non-heterosexual identity. Thus, even if the outcome of Hurley were justifiable on the narrow grounds of free speech, the Court's rejection of the lower court's finding of discrimination leaves open an important question for future cases involving gay and lesbian discrimination: that is, how will the Court treat future discrimination cases that turn on expressive activity of gays and lesbians, or, more precisely, will the Court resolve future disputes over outness in a way that fosters gay and lesbian equality.This article considers these questions in three parts. In Part II, I discuss the legal and political history underlying the Hurley decision. I will specifically analyze the free speech framework applied in the Supreme Court opinion and contrast it with the Roberts test that governed the state courts' decisions. I will also discuss in greater detail the two compelling questions the decision raises. Parts III and IV attempt to answer these questions. In Part III, I examine the possible impact of Hurley upon the Roberts doctrine by analyzing how post-Hurley cases have treated speech and equality conflicts. I argue that the courts in these cases have rightfully limited the reach of Hurley and have preserved the balancing formula established in Roberts. In Part IV, I consider the negative implications, from a gay-sensitive perspective, that Hurley might have for cases involving discrimination on the basis of outness. Finally, I suggest a tentative approach for courts to follow in order to ensure that civil rights law recognizes the importance of outness and adequately protects gays, lesbians, and bisexuals from invidious discrimination.
The Triumph of Loyalty Over Competence: The Bush Administration and the Exhaustion of the Politicized Presidency

The most important administrative aspect of the George W. Bush presidency was not its formal management reform agenda, but its attempt to extend the politicized presidency. Efforts to assert tighter political control of the federal bureaucracy, revived during the Ronald Reagan administration, were pursued to an extreme under Bush. Loyalty triumphed over competence in selection, and political goals displaced rationality in decision making. However, the strategy of politicization undermined the Bush administration’s own policy goals as well as its broader agenda to restore the strength of the institutional presidency. This apparent failure of strategy signals the urgent necessity for a fundamental reconsideration of the politicized presidency.
What's Vol Got to Do with It

Uncertainty plays a key role in economics, finance, and decision sciences. Financial markets, in particular derivative markets, provide fertile ground for understanding how perceptions of economic uncertainty and cash-flow risk manifest themselves in asset prices. We demonstrate that the variance premium, defined as the difference between the squared VIX index and expected realized variance, captures attitudes toward uncertainty. We show conditions under which the variance premium displays significant time variation and return predictability. A calibrated, generalized long-run risks model generates a variance premium with time variation and return predictability that is consistent with the data, while simultaneously matching the levels and volatilities of the market return and risk-free rate. Our evidence indicates an important role for transient non-Gaussian shocks to fundamentals that affect agents' views of economic uncertainty and prices. The Author 2010. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org., Oxford University Press.
Optimal Dynamic Capital Budgeting

I study optimal design of a dynamic capital allocation process in an organization in which the division manager with empire-building preferences privately observes the arrival and properties of investment projects, and headquarters can audit projects at a cost. Under certain conditions, a budgeting mechanism with threshold separation of financing is optimal. Headquarters: (1) allocate a spending account to the manager and replenish it over time; (2) set a threshold, such that projects below it are financed from the account, while projects above are financed fully by headquarters upon an audit. Further analysis studies when co-financing of projects is optimal and how the size of the account depends on past performance of projects.
Religious Freedom and Doctrines of Reluctance in Post-Charter Canada

Among the varied documents forming part of the Canadian Constitution is the Canadian Charter of Rights and Freedoms, adopted in 1982. The Charter contains contemporary Canada's first written, constitutional guarantees of individual fundamental freedoms. The written form of the document diverges from the past, but will the scope of protection afforded religious freedom under the document differ from that previously afforded? Pre-Charter courts were hesitant to protect religious freedom. They developed four doctrines, or modes of analysis, that evidenced their reluctance to actively safeguard religious freedom. This Comment identifies these four doctrines and assesses the extent to which the Canadian Supreme Court has continued to adhere to these doctrines in the wake of the Charter of Rights and Freedoms. The Comment finds that the Court’s post-Charter jurisprudence reflects a willingness to shed or alter the doctrines of reluctance to provide greater protection for religious freedoms.
The analysis of country-to-country CDM permit trading using the gravity model in international trade

Abstract The fairness and effectiveness of the Clean Development Mechanism (CDM) in reducing greenhouse gas emissions and promoting economic development is a matter of substantial concern for the international community as it works towards another GHG reduction agreement in Copenhagen. Among other reasons, the CDM has been criticized as favoring some countries and disfavoring others, resulting in an imbalance in the distribution of development projects, thus undermining one of the original purposes of this institutional arrangement. In this paper, CDM projects were evaluated using econometric models based on international trade theory. Although the CDM suffers from imbalances as have been noted elsewhere, the primary determinant of CDM projects is the total GHG emissions from host and credit countries. GHG emissions in each were positively and consistently related to the CDM projects. Project size and the extent of a host country's infrastructure (such as road, rail lines, airports, electricity supply, telephone and internet connections) were each important determinants. Finally, results are discussed in the context of policy-based action that might limit or otherwise affect CDM implementation after the Copenhagen.
Asymmetric Competition in B2B Spot Markets

We model strategic behavior of two types of suppliers in B2B spot markets: a supplier that has forward contracts and uses the spot market only for inventory liquidation, and a supplier that uses the spot market as its sole selling channel. We find that when the spot market demand is small, the supplier that has forward contracts has a higher incentive to invest in expanding the spot market. When the spot market demand exceeds a threshold size, this situation is reversed, and the supplier with no contracts benefits more from making the spot market more prevalent. We show that a supplier with forward contracts benefits from the existence of the spot market more than a supplier with no contracts and that this result holds with both negative and positive correlation between spot market demand and contracted demand. We find that suppliers producing only for the spot market gain from working in industries where contracted demand and spot market demand are positively correlated, whereas suppliers that have forward contracts benefit from working in industries with a negative correlation between demands, since it allows them to better manage risk. In addition, both total industry supply and spot market supply are higher in industries where demands are negatively correlated.
Social Technology & the Origins of Popular Philanthropy

The prevailing theory of charity law holds that the charitable contribution deduction is justified because it solves market and government failures in charitable goods by compensating for free riding on charitable contributions. This Article argues that many market and government failures in charitable goods are actually caused by transaction costs, and that social technology can solve those market and government failures by reducing transaction costs. Specifically, it shows that in the early twentieth century, the social technology of charity chain letters solved market and government failures in charitable contributions and facilitated the emergence of popular philanthropy.
Smart fund managers? Stupid money?

We develop a model of mutual fund manager investment decisions near the end of quarters. We show that when investors reward better performing funds with higher cash flows, near quarter-ends a mutual fund manager has an incentive to distort new invest ment toward stocks in which his fund holds a large existing position. The short-term price impact of these trades increase the fund's reported returns. Higher returns are rewarded by greater subsequent fund inflows which, in turn, allow for more investment distortion the next quarter. Because the price impact of trades is short term, each subsequent quar ter begins with a larger return deficit. Eventually, the deficit cannot be overcome. Thus, our model leads to the empirically observed short-run persistence and long-run rever sal in fund performance. In doing so, our model provides a consistent explanation of many other seemingly contradictory empirical features of mutual fund performance. JEL classification: D82, G2, G14
The Jew Who Met Himmler - And Other Stories

In this article Prof. Goldman examines the historical origins of the international criminalization of genocide and the goals the author of the law hoped to achieve by its passage and enforcement. The article tells the story of a little known, yet remarkable historical incident that demonstrates how the fear of criminal consequences might act to deter even the most monstrous perpetrators of genocide; even the man who was most responsible for the implementation of the Holocaust, Nazi Reichsfuhrer Heinrich Himmler.
Information overload and viral marketing: countermeasures and strategies

Studying information diffusion through social networks has become an active research topic with important implications in viral marketing applications. One of the fundamental algorithmic problems related to viral marketing is the Influence Maximization (IM) problem: given an social network, which set of nodes should be considered by the viral marketer as the initial targets, in order to maximize the influence of the advertising message. In this work, we study the IM problem in an information-overloaded online social network. Information overload occurs when individuals receive more information than they can process, which can cause negative impacts on the overall marketing effectiveness. Many practical countermeasures have been proposed for alleviating the load of information on recipients. However, how these approaches can benefit viral marketers is not well understood. In our work, we have adapted the classic Information Cascade Model to incorporate information overload and study its countermeasures. Our results suggest that effective control of information overload has the potential to improve marketing effectiveness, but the targeting strategy should be re-designed in response to these countermeasures.
Institutional Determinants of Labor Reallocation in Transition

The transition process differed in the countries of the Former Soviet Union (FSU) and those of Central and Eastern Europe (CEE) in terms of reallocation of labor real wage, employment and output adjustment. We sift through the theoretical and empirical literature to find an explanation for these diverging adjustment trajectories and conclude that they can be explained by the fact that the CEE countries adopted social policies that upheld wages at the bottom of the distribution forcing the old sector to restructure or collapse while the FSU countries allowed wages to free-fall not forcing the hand of the old sector.
The distribution of power among corporate managers, shareholders, and directors

This article surveys the seventeen papers in this special issue of the Journal of Financial Economics, and related work. The major findings are: (1) patterns of stock ownership by insiders and outsiders can influence managerial behavior, corporate performance, and stockholder voting in election contests; (2) corporate leverage, inside stock ownership by managers, and the control market are interrelated; (3) departures from one share/one vote affect firm value and efficiency; (4) takeover resistance through defensive restructurings or poison pill provisions is associated with declines in share price; and (5) top management turnover is inversely related to share price performance.
Banking across Borders

Abstract The international linkages between banks play a crucial role in today's global economy. Existing models explain these links largely on the basis of portfolio theory, in which banks diversify lending. These models have found limited empirical support and do not speak to several relevant dimensions of the data. They do not explain heterogeneity in the degree to which banks operate through foreign affiliates, fund their activities abroad or matter for local lending in foreign countries. This paper proposes a complementary theory of banking across borders that is based on elements of international trade theory. In the model, banking across borders arises because countries differ in their relative factor endowments and in the efficiency of their banking sectors. Based on these differences, the pattern of foreign bank asset and liability holdings emerges endogenously. This parsimonious model provides a rationale for the observed heterogeneity in foreign bank activities and is consistent with key patterns in the data.
Law as a vanishing mediator in the theological ethics of Tariq Ramadan

Tariq Ramadan’s recent book, Radical Reform: Islamic Ethics and Liberation, boldly proclaims the need for Muslims to completely rethink the very meaning of Islamic law, traditionally the preeminent Islamic normative discourse and a primary distinguishing feature of Islam from other religions, replacing it with a more ecumenical applied ethics. He begins the book by rejecting the moderate reformist methods adopted in his previous books as insufficient for the ‘radical reform’ of their epistemologies and mentalities which he believes contemporary Muslims must undertake. It is tempting, therefore, to see this work as a radical break with Law. In this article, I offer a different interpretation. On my reading, throughout his previous works Ramadan systematically advanced and elevated a certain interpretation of Law, based on an appropriation of certain concepts taken from mainstream Islamic legal theory and crucial to the efforts of all reformist thinkers. It is these concepts, which he retains but completely...